The term influenza refers to illness caused by influenza virus. This is commonly called the flu, but many different illnesses cause flu-like symptoms such as fever, chills, aches and pains, cough, and sore throat. Influenza virus infection can cause different illness patterns, ranging from mild common cold symptoms to typical flu. Some people may be at increased risk for bacterial complications of influenza such as pneumonia, ear or sinus infections, or bloodstream infections.

There are a number of drugs approved by the FDA for the treatment and prevention of influenza. Yearly vaccination is the primary means of preventing and controlling influenza.

Antibiotics are used to treat illnesses caused by bacteria like strep throat, tuberculosis and many types of pneumonia. Antibiotics do not treat viral illnesses like flu, colds, and most sore throats.

Influenza and COVID-19

The worldwide pandemic of the disease called COVID-19 has changed the way people look at “flu-like” symptoms. COVID-19 is caused by a different virus, not an influenza virus but a coronavirus, called SARS-CoV-2. COVID-19 and influenza illnesses can have many of the same symptoms but may cause different risks of complications in some different risk groups and may need different testing, treatment, and preventive measures. These similarities and differences may be important considerations for healthcare providers and people who believe they may have been exposed or may have either of these illnesses. CDC has posted some comparisons between these two illnesses; information is accumulating and changing rapidly. The possible effect of COVID-19 exposure-avoidance measures on circulation of influenza is not fully understood. Currently approved influenza antivirals are not expected to provide benefit against COVID-19.

Use of Antiviral Medications to Treat Influenza

Outbreaks of influenza occur every year and typically reach epidemic levels at some part of the season. Usually, uncomplicated influenza gets better with or without antiviral treatment but may cause substantial discomfort and limit activities while it lasts.

Many people with uncomplicated influenza use over-the-counter medicines, get rest, and take plenty of fluids to lessen their symptoms. Antiviral drugs available by prescription can reduce the time it takes for symptoms to improve, and some are also used in selected situations to reduce the chance of illness in people exposed to influenza virus. Prompt medical evaluation is important for early treatment of influenza as the antiviral drugs may provide the most benefit for patients who initiate therapy within 48 hours of symptom onset.

Symptoms of influenza may mimic other infections which require different treatment (such as bacterial pneumonia which should be treated with antibiotics). It is important to be evaluated by a healthcare provider, if symptoms are severe or worsening or if there is an underlying chronic medical condition. Laboratory tests can help detect influenza virus. However, a negative test does not always rule out the possibility of an influenza virus infection, and positive tests do not exclude the possibility of other illnesses or take the place of clinical evaluation.

Complications of influenza can include bacterial infections, viral pneumonia, and cardiac and other organ system abnormalities. People with chronic medical conditions (including obesity), children younger than 5 years old (and especially children less than 2 years old), patients 65 years and older, residents of long-term care facilities, Native Americans and Alaska Natives and pregnant women may be at increased risk for complications. Complications of influenza, and other illnesses that resemble influenza, may require different treatment and, in some cases, urgent medical attention. Antiviral drugs do not eliminate the risk of complications. Some complications can be life-threatening. There have been reports of people with other types of infections that got worse because they were treated only for influenza and not for the other infections.

Influenza viruses can become resistant to specific anti-influenza antiviral drugs, and all of these drugs have side effects. If you experience new symptoms during treatment or your symptoms persist or get worse during treatment, see your health care professional.

FDA Approved Drugs for Influenza

Note: Influenza antiviral drugs are not a substitute for vaccine. They are used in addition to vaccine in public health planning for the control of influenza. The antiviral drugs have been approved for treatment of acute uncomplicated influenza and for some preventive uses.

There are four FDA-approved influenza antiviral drugs recommended by CDC for use against recently circulating influenza viruses.

• Rapivab (peramivir)
• Relenza (zanamivir)
• Tamiflu (oseltamivir phosphate, also available as generic)
• Xofluza (baloxavir marboxil)

Two older drugs, amantadine (generic) and rimantadine (Flumadine and generic) historically have been approved for treatment and prevention of influenza A virus infection. But many strains of influenza virus, including the 2009 H1N1 influenza virus, are now resistant to these drugs. CDC has not recommended the use of amantadine and rimantadine for recently circulating influenza viruses, although recommendations could change if there were future re-emergence of specific virus strains with susceptibility patterns favoring such use.

Use of Investigational Drugs for Influenza

Clinical trials evaluate the safety and efficacy of unapproved products or new uses for approved products. Information about open clinical trials can be found at ClinicalTrials.gov.

Influenza (flu) is a serious disease, caused by influenza viruses, that can lead to hospitalization and even death. Your best defense is vaccination, which provides protection from flu and its potential complications.

Flu viruses typically spread in fall and winter, with activity peaking between December and February. Every flu season is different, and the health impacts can be substantial and vary widely from season to season, with some flu seasons being worse than others.

Flu viruses can change from year to year, so the vaccine is updated every year to protect against new flu virus strains that are expected to circulate and cause illness in the U.S. The FDA plays a key role in making sure flu vaccines are safe, effective, and of high quality.

The FDA is responsible for ensuring that the supply of the following is safe and effective:

• Flu vaccines
• Flu antiviral drugs

Flu Vaccines

The flu viruses that circulate and cause disease in people often change from one year to another. Every year there is a new flu vaccine to protect against the flu viruses that are expected to be prevalent in the U.S. during the upcoming flu season. Therefore, it is important for you to get vaccinated every year.

Flu Antiviral Drugs

Flu antiviral medications are prescription pills, liquids, or inhalers used to prevent or treat flu. They are approved for adults, children and infants as young as two weeks.

• If you get the flu, antiviral medications can make you feel better faster. Antiviral medications work best when started within the first two days of getting sick.
• If you are exposed to the flu, antiviral medication can help prevent you from becoming sick. Talk to your health care provider if you have been or may be near a person with the flu.

Flu and COVID-19

The flu viruses and the virus that causes COVID-19 will likely circulate together this fall and winter.

The flu vaccine will not prevent COVID-19. The flu vaccines are approved by the FDA for the prevention of influenza disease, so getting vaccinated can help keep you out of the doctor’s office and preserve health care resources for patients with other diseases and medical conditions, including COVID-19.

COVID-19 vaccines can help protect against severe illness, hospitalization and death from COVID-19.

Availability and Shortages

To report a shortage of a flu antiviral drug, send an email to drugshortages@fda.hhs.gov or call 888-INFO-FDA (888-463-6332) or 301-796-3400.

To report a shortage of a flu vaccine, send an email to CBERshortage@fda.hhs.gov or call 240-402-8380.

Children and Flu

Although children younger than 6 months are too young to be vaccinated, they have the highest risk for being hospitalized because of flu and flu-related complications compared to children of other ages. Therefore, the Centers for Disease Control and Prevention (CDC) recommends that parents, grandparents, caregivers, and all household members 6 months of age and older should be vaccinated because they will be less likely to get the flu and spread it to the unvaccinated child. If possible, keep infants away from crowds for the first few months of life.

Can flu be treated?

Yes. There are prescription medications called “antiviral drugs” that can be used to treat flu illness. CDC recommends prompt treatment for people who have flu or suspected flu and who are at higher risk of serious flu complications, such as people with asthma, diabetes (including gestational diabetes), or heart disease.

What are flu antiviral drugs?

Flu antiviral drugs are prescription medicines (pills, liquid, an inhaled powder, or an intravenous solution) that fight against flu viruses in your body. Antiviral drugs are not sold over the counter. You can only get them if you have a prescription from a health care provider. Antiviral drugs are different from antibiotics, which fight against bacterial infections. Antiviral drugs for flu only work to treat flu. Flu antiviral drugs are different than antiviral drugs used to treat other infectious diseases such as COVID-19. Antiviral drugs prescribed to treat COVID-19 do not work to treat flu.

What should I do if I think I am sick with flu?

If you get sick with flu, antiviral drugs are a treatment option. Check with your doctor promptly if you are at higher risk of serious flu complications (full list of higher risk factors) and you develop flu symptoms. Flu signs and symptoms can include feeling feverish or having a fever, cough, sore throat, runny or stuffy nose, body aches, headache, chills, and fatigue. Your doctor may prescribe antiviral drugs to treat your flu illness.

Should I still get a flu vaccine?

Yes. Antiviral drugs are not a substitute for getting a flu vaccine. While flu vaccine can vary in how well it works, a flu vaccine is best way to help prevent seasonal flu and its potentially serious complications. Everyone 6 months and older should receive a flu vaccine every year. Antiviral drugs are a second line of defense that can be used to treat flu (including seasonal flu and variant flu viruses) if you get sick.

What are the benefits of antiviral drugs?

Antiviral treatment works best when started soon after flu illness begins. When treatment is started within two days of becoming sick with flu symptoms, antiviral drugs can lessen fever and flu symptoms and shorten the time you are sick by about one day. They also may reduce the risk of complications such as ear infections in children, respiratory complications requiring antibiotics, and hospitalization in adults. For people at higher risk of serious flu complications, early treatment with an antiviral drug can mean having milder illness instead of more severe illness that might require a hospital stay. For adults hospitalized with flu illness, some studies have reported that early antiviral treatment can reduce their risk of death.

When should antiviral drugs be taken for treatment?

Studies show that flu antiviral drugs work best for treatment when they are started within two days of getting sick. However, starting them later can still be beneficial, especially if the sick person is at higher risk of serious flu complications or is in the hospital with more severe illness. Follow instructions for taking these drugs. Follow your doctor’s and the dose, frequency, and duration listed on the label instructions for taking these drugs.

What antiviral drugs are recommended this flu season?

There are four FDA-approved antiviral drugs recommended by CDC to treat flu this season.

• oseltamivir phosphate (available as a generic version or under the trade name Tamiflu®),
• zanamivir (trade name Relenza®)
• peramivir (trade name Rapivab®), and
• baloxavir marboxil (trade name Xofluza®).

Generic oseltamivir and Tamiflu® are available as a pill or liquid suspension and are FDA approved for early treatment of flu in people 14 days and older. Zanamivir is a powder that is inhaled and approved for early treatment of flu in people 7 years and older. (Note: Zanamivir (trade name Relenza®) is administered using an inhaler device and is not recommended for people with breathing problems like asthma or COPD.) Oseltamivir and zanamivir are given twice a day for five days. Peramivir is given once intravenously by a health care provider and is approved for early treatment of flu in people 6 months and older. Baloxavir is a pill given as a single dose by mouth and is approved for early treatment of flu in children aged 5 years to less than 12 years who do not have any chronic medical conditions, and for all people aged 12 years and older. (Note: Baloxavir (trade name Xofluza®) is not recommended for pregnant people, breastfeeding people, outpatients with complicated or progressive illness, or hospitalized patients because there is no information about use of baloxavir in these patients.)

How long should antiviral drugs be taken?

To treat flu, oseltamivir or inhaled zanamivir are usually prescribed for five days, or one dose of intravenous peramivir or oral Baloxavir for one day. Oseltamivir treatment is given to hospitalized patients, and some patients might be treated for more than five days.

What are the possible side effects of antiviral drugs?

Side effects vary for each medication. The most common side effects for oseltamivir are nausea and vomiting. Zanamivir can cause bronchospasm, and peramivir can cause diarrhea. Other less common side effects also have been reported. Your health care provider can give you more information about these drugs or you can check the Food and Drug Administration (FDA) website for specific information about antiviral drugs, including the manufacturer’s package insert.

Children and Flu Antiviral Drugs

Parents, if your child gets sick with flu, antiviral drugs offer a safe and effective treatment option. For treatment, influenza antiviral drugs should ideally be started within 2 days after becoming sick and taken according to your doctor’s instructions (usually for 5 days).

Can children take antiviral drugs?

Yes, though this varies by medication. Oseltamivir is recommended by CDC for treatment of flu in children beginning from birth and the American Academy of Pediatrics (AAP) recommends oseltamivir for treatment of flu in children 2 weeks old or older. Oseltamivir is available as an oral suspension for children. Zanamivir is approved for early treatment of flu in people 7 years and older, though it is not recommended for use in children with underlying respiratory disease, including asthma and other chronic lung diseases. Peramivir is approved for early treatment in people 6 months and older. Baloxavir is approved for early treatment of flu in children aged 5 to less than 12 years who do not have any chronic medical conditions, and for all children aged 12 years and older. Baloxavir is available as an oral suspension for children.

If your child’s health care provider prescribes oseltamivir capsules for your child and your child cannot swallow capsules, the prescribed capsules may be opened, mixed with a thick sweetened liquid, and given that way. Learn more here.

Can pregnant people take antiviral drugs?

Yes. Oral oseltamivir is recommended for treatment of pregnant people with flu because compared to other recommended antiviral medications, it has the most studies available to suggest that it is safe and beneficial during pregnancy. Baloxavir is not recommended for pregnant people or while breastfeeding, as there are no available efficacy or safety data.

Who should take antiviral drugs?

It’s very important that flu antiviral drugs are started as soon as possible to treat patients who are hospitalized with flu, people who are very sick with flu but who do not need to be hospitalized, and people who are at higher risk of serious flu complications based on their age or health, if they develop flu symptoms. Although other people with mild illness who are not at higher risk of flu complications may also be treated early with antiviral drugs by their doctor, most people who are otherwise healthy and not at higher risk for flu complications do not need to be treated with antiviral drugs.

Following is a list of all the health and age factors that are known to increase a person’s risk of getting serious complications from flu:

• Asthma
• Neurologic and neurodevelopment conditions
• Blood disorders (such as sickle cell disease)
• Chronic lung disease (such as chronic obstructive pulmonary disease [COPD] and cystic fibrosis)
• Endocrine disorders (such as diabetes mellitus)
• Heart disease (such as congenital heart disease, congestive heart failure and coronary artery disease)
• Kidney disorders
• Liver disorders
• Metabolic disorders (such as inherited metabolic disorders and mitochondrial disorders)
• People who are obese with a body mass index [BMI] of 40 or higher
• People younger than 19 years of age on long-term aspirin- or salicylate-containing medications.
• People with a weakened immune system due to disease (such as people with HIV or AIDS, or some cancers such as leukemia) or medications (such as those receiving chemotherapy or radiation treatment for cancer, or persons with chronic conditions requiring chronic corticosteroids or other drugs that suppress the immune system)

Other people at higher risk from flu:

• Adults 65 years and older
• Children younger than 2 years old¹
• Pregnant women and women up to 2 weeks after the end of pregnancy
• American Indians and Alaska Natives
• People who live in nursing homes and other long-term care facilities
• ¹ Although all children younger than 5 years old are considered at higher risk for serious flu complications, the highest risk is for those younger than 2 years old, with the highest hospitalization and death rates among infants younger than 6 months old.

Rapivab (peramivir) is an injectable anti-viral drug approved for the treatment of acute uncomplicated influenza in patients 2 years of age and older who have been symptomatic for no more than 2 days. This product is approved to treat Type A and B influenza; however, the majority of patients included in the studies were infected with type A, the most common in the U.S. The efficacy of Rapivab could not be established in patients with serious influenza requiring hospitalization.

Rapivab is not approved for the prevention of influenza.

Rapivab is not a substitute for early influenza vaccination on an annual basis.

Relenza (zanamivir) is an inhalation powder for oral inhalation approved for treatment of acute uncomplicated illness due to influenza A and B virus in adults and pediatric patients aged 7 years of age and older who have been symptomatic for no more than 2 days.

Relenza is indicated for preventive use (prophylaxis) in adults and pediatric patients aged 5 years of age and older.

Relenza is not a substitute for early influenza vaccination on an annual basis.

Tamiflu (oseltamivir phosphate) is an oral anti-viral drug approved for the treatment of acute, uncomplicated influenza in patients 2 weeks of age and older whose flu symptoms have not lasted more than two days. This product is approved to treat Type A and B influenza; however, the majority of patients included in the studies were infected with type A, the most common in the U.S. Efficacy of Tamiflu in the treatment of influenza in subjects with chronic cardiac disease and/or respiratory disease has not been established.

Tamiflu is also approved for the prevention of influenza in adults and children aged one year and older. Efficacy of Tamiflu for the prevention of influenza has not been established in immunocompromised patients.

Tamilfu is not a substitute for early influenza vaccination on an annual basis.

Q. What is Tamiflu and what is it approved for?

A. Tamiflu (oseltamivir phosphate) is an antiviral drug. It works by attacking the flu virus to keep it from multiplying in your body and by reducing the symptoms of the flu. Tamiflu can sometimes keep you from getting the flu if you take it before you get sick.

The term "flu" refers to illness caused by the influenza virus. The flu is a respiratory infection that can cause symptoms such as fever, chills, aches and pains, cough, and sore throat. The flu can range from mild common cold symptoms, to the typical "flu" symptoms described above, to life-threatening pneumonia and other complications, including secondary bacterial infections.

Tamiflu is used to treat people 2 weeks of age and older who have the flu (influenza A and B viruses). Tamiflu is also sometimes used for prevention (prophylaxis) of the flu in people 1 year of age and older, but it is not a substitute for getting the flu vaccine.

Q. Is Tamiflu a substitute for the flu vaccine?

A. No. Getting the flu vaccine is the best way to protect against getting the flu and to control the spread of the flu.

Other important parts of avoiding flu include avoiding unnecessary close contact between sick and well people, covering coughs and sneezes, and washing hands frequently.

Q. What do the terms treatment of the flu and prevention (prophylaxis) of the flu mean?

A. Treatment is used when a person is given Tamiflu because they have the signs and symptoms of the flu or have been diagnosed with the flu. Tamiflu has been shown to lessen the amount of time people are sick with the flu.

Prevention (prophylaxis) is a term used when someone who does not have flu symptoms is given Tamiflu to help stop them from getting the flu because they are exposed to or come into close contact with someone (for example live with or take care of someone) who has the flu.

Q. Do I take Tamiflu the same way for treatment and prevention (prophylaxis) of the flu?

A. No. The number of times a day (frequency) and the number of days (duration) that you take Tamiflu are different for treatment and prevention of the flu. Your healthcare provider will tell you how to take Tamiflu. Take it exactly as your healthcare provider prescribes.

Q. What should people do if they continue to have or start to develop flu symptoms while taking Tamiflu?

A. If flu symptoms do not go away, or if new symptoms develop while taking Tamiflu, people should contact their healthcare provider. Other illnesses may cause people to have symptoms similar to the flu, or may occur at the same time as the flu, and they might need other treatment.

Q. Does Tamiflu come in a liquid as well as capsules?

A. Yes, Tamiflu is available as a liquid (oral suspension) and as oral capsules of different sizes. Your healthcare provider will prescribe the strength that is right for you.

Q. Do I need to make the Tamiflu liquid (oral suspension)?

A. No, a pharmacist should mix Tamiflu liquid before giving it to you. If you get a bottle with only powder in it, you should return the medication to the pharmacy so it can be mixed correctly.

Q. Is there enough Tamiflu suspension?

A. At some times there might not be enough of the pre-packaged liquid Tamiflu made by the manufacturer. Some pharmacies may need to make a liquid for patients from the pills instead. You should always follow the directions on the medicine label for how much and how often to give the medication. You should speak with your healthcare provider if you have any questions.

Q. Does the liquid (oral suspension) need to be refrigerated?

A. Yes, liquid Tamiflu (oral suspension) should be stored in the refrigerator. Ask the pharmacist how long to keep the medicine, and then throw away the unused medicine after that time. You should only use the medication for as long as your healthcare provider has directed.

Q. Does liquid Tamiflu (oral suspensions) need to be shaken?

A. Yes, shake liquid Tamiflu well each time before you give it.

Q. What do I use to give liquid Tamiflu (oral suspension)?

A. The pharmacist should give you a syringe to measure the dose of liquid Tamiflu. You and your pharmacist should look at the syringe and compare it to the directions on the medicine label. You should be able to use the syringe to measure the right amount that is written on the medicine label. If you have any questions about whether the measurements on the syringe, the medication label, and the prescription are all the same, make sure that you and your pharmacist and your doctor have answered those questions before you use the Tamiflu.

Q. What should I do if I am given Tamiflu capsules but can not swallow them?

A. If you have trouble swallowing Tamiflu capsules, you should tell your healthcare provider. Adults and children 1 year of age and older can be correctly dosed with capsules even if they can not swallow the capsules. If liquid Tamiflu is not available and you have capsules that give the right dose (30 mg, 45 mg or 75 mg), you may pull open the Tamiflu capsules and mix the powder with a small amount of sweetened liquid such as regular or sugar-free chocolate syrup. You don’t have to use chocolate syrup but thick, sweet liquids work best at covering up the taste of the medicine.

Q. Should women who are pregnant or nursing take Tamiflu?

A. Tamiflu may be of benefit for some pregnant and nursing women. At this time, the U.S. Centers for Disease Control and Prevention (CDC) recommends that pregnant women who are sick from influenza should be treated with a flu drug because of concerns that they could develop more severe illness. Pregnant and nursing women are advised to talk with a healthcare professional before using Tamiflu.

Q. What are the most common side effects of Tamiflu?

A. The most common side effects of Tamiflu are nausea and vomiting. Usually, nausea and vomiting are not severe and happen in the first 2 days of treatment. Taking Tamiflu with food may lessen the chance of getting these side effects. Other side effects include stomach (abdominal) pain, nosebleeds, headache, and feeling tired (fatigue).

Q. What are the serious side effects of Tamiflu?

A. Children and teenagers with the flu may be at a higher risk for seizures, confusion, or abnormal behavior early during their illness. These serious side effects may happen shortly after beginning Tamiflu or may happen in people when the flu is not treated. These serious side effects are not common but may result in accidental injury to the patient. People who take Tamiflu should be watched for signs of unusual behavior and a healthcare provider should be contacted right away if the patient shows any unusual behavior while taking Tamiflu.

Rare cases of allergic reactions, including serious skin rashes, have happened in people who take Tamiflu. If a rash develops, stop taking Tamiflu and contact a healthcare provider right away.

FDA encourages consumers to report any side effects and medication errors from Tamiflu to FDA at 1-800-FDA-1088.

What is baloxavir marboxil?

Baloxavir marboxil (trade name Xofluza®) is an influenza (flu) antiviral drug given as a pill in a single dose by mouth that was approved on October 24, 2018, by the U.S. Food and Drug Administration (FDA).

Who can take baloxavir?

Baloxavir is currently approved by the FDA for treatment of flu in children aged 5 years to less than 12 years who do not have any chronic medical conditions, and for all people aged 12 years and older. Baloxavir also is approved by the FDA for post-exposure prophylaxis of flu in people aged 5 years and older. CDC does not recommend use of baloxavir in pregnant people, breastfeeding people, outpatients with complicated or progressive illness, severely immunosuppressed people, or hospitalized patients because of the lack of information on use of baloxavir for these groups to date.

How is baloxavir given?

Baloxavir is available as an oral suspension for children or as tablet, given as a single dose by mouth. (The oral suspension when constituted by the pharmacy has a concentration of 2 mg/kg. There are also 20 mg and 40 mg tablets and dosage depends on patient weight.)

What other antiviral drugs for flu are available?

In the United States, there are four FDA-approved antiviral drugs recommended by CDC this season:

• oseltamivir (available as a generic version or under the trade name Tamiflu®)
• zanamivir (trade name Relenza®)
• peramivir (trade name Rapivab®), and
• baloxavir (trade name Xofluza®).

Where can I get baloxavir?

Antiviral drugs for flu treatment are not sold over the counter. You can only get them from a pharmacy if you have a prescription from your doctor or health care provider. More information regarding supply of antiviral drugs is available.

Why was there a need for a different antiviral drug for flu?

Baloxavir works differently than the other currently recommended flu antiviral drugs, which are neuraminidase inhibitors (oseltamivir, zanamivr and peramivir). Given how frequently flu viruses change and the potential for flu viruses to develop resistance or reduced susceptibility to one or more flu antiviral drugs, it is good to have more options for treating flu. For example, flu viruses that are resistant to oseltamivir should still be susceptible to baloxavir.

Can antiviral resistance to baloxavir occur?

Reduced susceptibility and antiviral resistance mean, respectively, that a flu virus has changed in such a way that antiviral drugs are less effective or not effective at all in treating or preventing illnesses with that flu virus. Flu viruses can develop reduced susceptibility or resistance to one or more antiviral drugs, including baloxavir. In randomized clinical trials, there was evidence of development of reduced susceptibility in some patients treated with baloxavir.

What’s the Bottom Line?

What do we know about the effectiveness of complementary approaches for flu and colds?

• No complementary health approach has been shown to be helpful for the flu.
• For colds:
  • Complementary approaches that have shown some promise include oral zinc products, rinsing the nose and sinuses (with a neti pot or other device), honey (as a nighttime cough remedy for children), vitamin C (for people under severe physical stress), probiotics, and meditation.
  • Approaches for which the evidence is conflicting, inadequate, or mostly negative include vitamin C (for most people), echinacea, garlic, and American ginseng.

What do we know about the safety of complementary approaches for colds and flu?

• People can get severe infections if they use neti pots or other nasal rinsing devices improperly. Tap water isn’t safe for use as a nasal rinse unless it has been filtered, treated, or processed in specific ways.
• Zinc products used in the nose (such as nasal gels and swabs) have been linked to a long-lasting or even permanent loss of the sense of smell.
• Using a dietary supplement to prevent colds often involves taking it for long periods of time. However, little is known about the long-term safety of some dietary supplements studied for prevention of colds, such as American ginseng and probiotics.
• Complementary approaches that are safe for some people may not be safe for others. Your age, health, special circumstances (such as pregnancy), and medicines or supplements that you take may affect the safety of complementary approaches.

Some Basics About Flu and Colds

Each year, Americans get more than 1 billion colds, and between 5 and 20 percent of Americans get the flu. The two diseases have some symptoms in common, and both are caused by viruses. However, they are different conditions, and the flu is more severe. Unlike the flu, colds generally don’t cause serious complications, such as pneumonia, or lead to hospitalization.

No vaccine can protect you against the common cold, but vaccines can protect you against the flu. Everyone over the age of 6 months should be vaccinated against the flu each year. Vaccination is the best protection against getting the flu.

Prescription antiviral drugs may be used to treat the flu in people who are very ill or who are at high risk of flu complications. They’re not a substitute for getting vaccinated. Vaccination is the first line of defense against the flu; antivirals are the second. If you think you’ve caught the flu, you may want to check with your health care provider to see whether antiviral medicine is appropriate for you. Call promptly. The drugs work best if they’re used early in the illness.

What the Science Says About Complementary Health Approaches for the Flu

No complementary approach has been shown to prevent the flu or relieve flu symptoms.

Complementary approaches that have been studied for the flu include the following. In all instances, there’s not enough evidence to show whether the approach is helpful.

• American ginseng
• Chinese herbal medicines
• Echinacea
• Elderberry
• Green tea
• Oscillococcinum
• Vitamin C
• Vitamin D

What the Science Says About Complementary Health Approaches for Colds

The following complementary health approaches have been studied for colds:

American Ginseng

• Several studies have evaluated the use of American ginseng (Panax quinquefolius) to prevent colds. A 2011 evaluation of these studies concluded that the herb has not been shown to reduce the number of colds that people catch, although it may shorten the length of colds. The researchers who conducted the evaluation concluded that there was insufficient evidence to support the use of American ginseng for preventing colds.
• Taking American ginseng in an effort to prevent colds means taking it for prolonged periods of time. However, little is known about the herb’s long-term safety. American ginseng may interact with the anticoagulant (blood thinning) drug warfarin.

Echinacea

• At least 24 studies have tested echinacea to see whether it can prevent colds or relieve cold symptoms. A comprehensive 2014 assessment of this research concluded that echinacea hasn’t been convincingly shown to be beneficial. However, at least some echinacea products might have a weak effect.
• One reason why it’s hard to reach definite conclusions about this herb is that echinacea products vary greatly. They may contain different species (types) of the plant and be made from different plant parts (the above-ground parts, the root, or both). They also may be manufactured in different ways, and some products contain other ingredients in addition to echinacea. Research findings on one echinacea product may not apply to other products.
• Few side effects have been reported in studies of echinacea. However, some people are allergic to this herb, and in one study in children, taking echinacea was linked to an increase in rashes.

Garlic

• A 2014 evaluation of the research on garlic concluded that there isn’t enough evidence to show whether this herb can help prevent colds or relieve their symptoms.
• Garlic can cause bad breath, body odor, and other side effects. Because garlic may interact with anticoagulant drugs (blood thinners), people who take these drugs should consult their health care providers before taking garlic.

Honey

• Honey’s traditional reputation as a cough remedy has some science to back it up. A small amount of research suggests that honey may help to decrease nighttime coughing in children.
• Honey should never be given to infants under the age of 1 year because it may contain spores of the bacterium that causes infant botulism. Honey is considered safe for older children.

Meditation

• Reducing stress and improving general health may protect against colds and other respiratory infections. In a 2012 study funded by the National Center for Complementary and Integrative Health (NCCIH), adults aged 50 and older were randomly assigned to training in mindfulness meditation, which can reduce stress; an exercise training program, which may improve physical health; or a control group that didn’t receive any intervention. The study participants kept track of their illnesses during the cold and flu season. People in the meditation group had shorter and less severe acute respiratory infections (most of which were colds) and lost fewer days of work because of these illnesses than those in the control group. Exercise also had some benefit, but not as much as meditation.
• This study is the first to suggest that meditation may reduce the impact of colds. Because it’s the only study of its kind, its results shouldn’t be regarded as conclusive.
• Meditation is generally considered to be safe for healthy people. However, there have been reports that it might worsen symptoms in people with certain chronic physical or mental health problems. If you have an ongoing health issue, talk with your health care provider before starting meditation.

Probiotics

• A 2015 evaluation of 13 studies found some evidence suggesting that probiotics might reduce the number of colds or other upper respiratory tract infections that people catch and the length of the illnesses, but the quality of the evidence was low or very low.
• In people who are generally healthy, probiotics have a good safety record. Side effects, if they occur at all, usually consist only of mild digestive symptoms such as gas. However, information on the long-term safety of probiotics is limited, and safety may differ from one type of probiotic to another. Probiotics have been linked to severe side effects, such as dangerous infections, in people with serious underlying medical problems.

Saline Nasal Irrigation

• Saline nasal irrigation means rinsing your nose and sinuses with salt water. People may do this with a neti pot (a device that comes from the Ayurvedic tradition) or with other devices, such as bottles, sprays, pumps, or nebulizers. Saline nasal irrigation may be used for sinus congestion, allergies, or colds.
• There’s limited evidence that saline nasal irrigation can help relieve cold symptoms. Studies of this technique have been too small to allow researchers to reach definite conclusions.
• Saline nasal irrigation used to be considered safe, with only minor side effects such as nasal discomfort or irritation. However, in 2011, a severe disease caused by an amoeba (a type of microorganism) was linked to nasal irrigation with tap water. The U.S. Food and Drug Administration (FDA) has warned that tap water that is not filtered, treated, or processed in specific ways is not safe for use in nasal rinsing devices and has explained how to use and clean these devices safely.

Vitamin C

• An evaluation of the large amount of research done on vitamin C and colds (29 studies involving more than 11,000 people) concluded that taking vitamin C doesn’t prevent colds in the general population and shortens colds only slightly. Taking vitamin C only after you start to feel cold symptoms doesn’t affect the length or severity of the cold.
• Unlike the situation in the general population, vitamin C does seem to reduce the number of colds in people exposed to short periods of extreme physical stress (such as marathon runners and skiers). In studies of these groups, taking vitamin C cut the number of colds in half.
• Taking too much vitamin C can cause diarrhea, nausea, and stomach cramps. People with the iron storage disease hemochromatosis should avoid high doses of vitamin C. People who are being treated for cancer or taking cholesterol-lowering medications should talk with their health care providers before taking vitamin C supplements.

Zinc

• Zinc has been used for colds in forms that are taken orally (by mouth), such as lozenges, tablets, or syrup, or used intranasally (in the nose), such as swabs or gels.
• Oral Zinc
  • A 2012 evaluation of 17 studies of various types of zinc lozenges, tablets, or syrup found that zinc can reduce the duration of colds in adults. Two evaluations of three studies of high-dose zinc acetate lozenges in adults, conducted in 2015 and 2016, found that they shortened colds.
  • Some participants in studies that tested zinc for colds reported that the zinc caused a bad taste or nausea.
  • Long-term use of high doses of zinc can cause low copper levels, reduced immunity, and low levels of HDL cholesterol (the “good” cholesterol). Zinc may interact with drugs, including antibiotics and penicillamine (a drug used to treat rheumatoid arthritis).
• Intranasal Zinc
  • The use of zinc products inside the nose, such as gels or swabs, may cause loss of the sense of smell, which may be long-lasting or permanent. In 2009, the FDA warned consumers to stop using several intranasal zinc products marketed as cold remedies because of this risk.
  • Prior to the warnings about effects on the sense of smell, a few studies of intranasal zinc had suggested a possible benefit against cold symptoms. However, the risk of a serious and lasting side effect outweighs any possible benefit in the treatment of a minor illness.

Other Complementary Approaches

In addition to the complementary approaches described above, several other approaches have been studied for colds. In all instances, there is insufficient evidence to show whether these approaches help to prevent colds or relieve cold symptoms.

• Andrographis (Andrographis paniculata)
• Chinese herbal medicines
• Green tea
• Guided imagery
• Hydrotherapy
• Vitamin D
• Vitamin E

NCCIH-Funded Research

NCCIH-supported researchers are conducting a variety of studies relevant to the flu or colds.

Topics of recent research include:

• Whether probiotics can enhance older adults’ response to flu vaccine
• Meditation and exercise for preventing acute respiratory infection
• How psychosocial factors, such as the quantity and quality of social relationships, influence the likelihood of catching colds
• The effects of echinacea on the immune system.

More To Consider

• Complementary health approaches should never be used as a substitute for flu vaccination.
• Tell all your health care providers about any complementary health approaches you use. Give them a full picture of what you do to manage your health. This will help ensure coordinated and safe care

The fall and winter flu season may bring out dishonest sellers hawking fraudulent products to unsuspecting consumers.

Some of these sellers illegally offer unproven products that claim to prevent, mitigate, treat, or cure the flu – even though they have not been evaluated or approved by the U.S. Food and Drug Administration for safety and effectiveness. These products can be found online, including popular marketplaces, and in retail stores. They may be labeled as dietary supplements, foods, hand sanitizers, nasal sprays, or devices.

These products might be dangerous to you and your family. The FDA urges consumers to avoid fraudulent flu products and offers some tips on how to spot them.

A Flu Vaccine Is the Best Prevention

Flu is a serious disease, caused by influenza viruses, that can lead to hospitalization and even death. Getting a flu vaccine is the best way to prevent this infectious disease and its serious complications.

The Centers for Disease Control and Prevention recommend that everyone age 6 months and older get vaccinated every year against influenza. This is particularly so for people at an increased risk for serious complications, including young children, adults 65 years and older, and those with chronic medical conditions. For more information on flu vaccine recommendations, visit this CDC page.

The FDA has approved numerous vaccines for the prevention of influenza. To find a flu vaccine near you, visit this page.

FDA-Approved Antiviral Medications for Flu

If you do get the flu, there are FDA-approved antiviral drugs, available by prescription from your health care professional, to treat it. There are several FDA-approved antiviral drugs recommended by the CDC for use against circulating influenza viruses. These drugs work best if started soon after the onset of symptoms (within 48 hours).

Flu antiviral medications are used to prevent or treat flu and are available by prescription in the form of pills, liquids, inhalers, and intravenous infusion. The various products are all approved for adolescent and adult use, and they differ in the ages for which they are approved to treat infants and children, ranging from 2-weeks-old to age 12.

If you get the flu, antiviral medications can make your illness milder and may make you feel better faster. Antiviral medications work best when started within the first two days of getting sick.

If you are exposed to the flu, antiviral medication can help prevent you from becoming sick. Talk to your health care professional if you have been or may be near a person with the flu.

If you think you have the flu, talk to your health care professional. There are FDA-approved drugs to help with the flu.

Types of Fraudulent Flu Products

There are no legally marketed over-the-counter (OTC, or non-prescription) drugs to prevent, treat, or cure the flu. But there are legally marketed OTC drugs to reduce fever and to relieve muscle aches, congestion, and other symptoms typically associated with the flu.

Dietary supplements, conventional foods (such as some herbal teas), or devices (such as certain air filters and light therapies) that fraudulently claim to prevent, mitigate, treat, or cure the flu have not been evaluated by the FDA for safety and effectiveness.

The FDA is particularly concerned that fraudulent products might cause people to delay, forgo, or stop the medical treatment they need, leading to serious and life-threatening harm. The ingredients in fraudulent products could lead to unexpected side effects and interactions with other medications people may be taking.

Protect yourself and your family by looking out for potentially fraudulent flu and antiviral products being sold without a prescription, which may claim to:

• Reduce the severity and length of flu or other viral infections.
• Boost your immunity naturally without a flu vaccine.
• Act as a safe and effective alternative to the flu vaccine.
• Prevent catching the flu or viral infections.
• Be an effective treatment for flu or viral infections.
• Provide faster recovery from the flu or viral infections.
• Support your body’s natural immune defenses to fight off flu or other viruses.

Find Out if Your Online Pharmacy Is Safe

Fraudsters take advantage of unsuspecting people through websites appearing to be online pharmacies selling prescription drugs.

Legitimate online pharmacies do exist. But so do many websites that look like safe online pharmacies but are actually fraudulent and engaging in illegal activity. These websites may be selling unapproved drugs that may be dangerous.

Unsure about an online pharmacy? Visit the FDA’s BeSafeRx campaign to learn how to safely buy prescription medicines online. If you have a question about a treatment or product, talk to your doctor or other health care professional.

There Are No FDA-Approved Homeopathic Products

At your pharmacy and online, you may see products being sold and advertised as homeopathic. The FDA is not aware of any proven benefits of these products.

Homeopathic products are generally labeled as containing very small amounts of highly diluted substances, including ingredients from plants, animal or human sources, bacteria, minerals, and chemicals. The FDA has found that some of these products contain active drug ingredients in levels that far exceed the amount stated on the product’s label and could cause significant harm to children. Therefore, we urge caution if you are thinking about giving homeopathic flu, cough, and cold medicines to children.

There are no FDA-approved homeopathic products. Homeopathic products sold in the U.S. have not been approved by the FDA for any use and may not meet modern standards for safety, effectiveness, and quality.

What are reduced susceptibility and antiviral resistance?

When an antiviral drug is fully effective against a virus, that virus is said to be susceptible to that antiviral drug. Flu viruses are constantly changing, and some changes can make antiviral drugs work less well or not work at all against these viruses. Antivirals drugs work by targeting a specific location or site found on a flu virus. When a flu virus develops changes to the site antiviral drugs use to work, that virus may show reduced or no susceptibility to that antiviral drug. Antiviral drugs may not work as well against viruses with reduced susceptibility. Flu viruses can show reduced susceptibility to one or more flu antiviral drugs. Reduced susceptibility detected using laboratory tests can be a sign of potential antiviral drug resistance in clinical settings. Typically, flu virus is called resistant after sufficient evidence was gathered to prove a lack of antiviral effect of a particular antiviral medication in patients infected with such virus.

In the United States, there are four FDA-approved antiviral drugs recommended by CDC this season. Three are neuraminidase inhibitor antiviral drugs: oseltamivir (available as a generic version or under the trade name Tamiflu®) for oral administration, zanamivir (trade name Relenza®) for oral inhalation using an inhaler device, and peramivir (trade name Rapivab®) for intravenous administration. The fourth is a cap-dependent endonuclease (CEN) inhibitor, baloxavir marboxil (trade name Xofluza®) for oral administration. Baloxavir marboxil was approved for use in the United States by FDA in October of 2018.

There is another class of FDA-approved antiviral drugs, M2 inhibitors amantadine and rimantadine, also called the adamantanes, that have activity against flu A viruses. They are not recommended for use in the United States for many years because of widespread antiviral resistance to this class of antivirals among circulating flu A viruses.

How widespread are reduced susceptibility and antiviral resistance in the United States?

In the United States, the majority of the recently circulating flu viruses have been fully susceptible to the neuraminidase inhibitors and to CEN inhibitor baloxavir. However, near all flu A viruses are resistant to the M2 inhibitors, which is why they are not recommended for use at this time.

How does reduced susceptibility and antiviral resistance happen?

Flu viruses are constantly changing; they can change in significant way from one season to the next and can even change within the course of one flu season. As a flu virus replicates (i.e., make copies of itself), the genetic makeup may change in a way that results in the virus becoming less susceptible to one or more of the antiviral drugs used to treat or prevent flu. Flu viruses can become less susceptible to antiviral drugs during the course of antiviral treatment or emerge spontaneously. Antiviral resistant flu viruses vary in their ability to infect people and are not necessarily more or less transmissible than susceptible flu viruses.

How are reduced susceptibility and antiviral resistance detected?

CDC routinely tests flu viruses collected through domestic and global surveillance to see if they have indications of reduced susceptibility to any of the FDA-approved flu antiviral drugs, as this can suggest the potential for antiviral resistance. In addition, numerous state public health laboratories participate in screening of additional viruses for genetic changes indicative of potential resistance to neuraminidase inhibitors. CDC also is collaborating with the Association of Public Health Laboratories (APHL) and the Wadsworth Center NYSDOH, a National flu Reference Center (NIRC), to establish additional laboratory-testing capacity for monitoring baloxavir susceptibility. This combined data informs public health policy recommendations about the use of flu antiviral medications.

CDC is continuously improving testing algorithms and methods used for monitoring antiviral susceptibility in circulating viruses. Detection of reduced susceptibility and antiviral resistance involves several laboratory tests, including phenotypic assays (testing in the presence of an antiviral) and molecular techniques (sequencing and pyrosequencing) to look for genetic changes that have been associated with reduced antiviral susceptibility.

How has CDC prepared to test for reduced susceptibility and antiviral resistance to the new flu antiviral baloxavir?

CDC’s Influenza Division took specific laboratory actions to incorporate the antiviral drug baloxavir into routine virologic surveillance. This included the creation and validation of new assays to determine baloxavir susceptibility, and training of laboratorians to conduct baloxavir susceptibility testing.

Seasonal flu A and B viruses in humans as well as several flu A viruses that circulate in animals were tested to established baseline susceptibility to baloxavir. In addition, the susceptibility of other distantly related flu viruses to baloxavir was tested. CDC also collaborated with the Association of Public Health Laboratories (APHL) and the Wadsworth Center NYSDOH, a National flu Reference Center (NIRC), to establish laboratory-testing capacity for baloxavir susceptibility. CDC has trained staff within these partner organizations to use CDC’s method for assessing baloxavir susceptibility.

What is oseltamivir resistance and what causes it?

Flu viruses are constantly changing. Changes that occur in circulating flu viruses typically involve the structures of the viruses’ two primary surface proteins: hemagglutinin (HA) and neuraminidase (NA) (See image below for a visualization of a flu virus and its HA and NA surface proteins.)

Oseltamivir is the most commonly prescribed antiviral drug of those recommended in the United States to treat flu illness. Oseltamivir is known as a “NA inhibitor” because this antiviral drug binds to NA proteins of a flu virus and inhibits the enzymatic activity of these proteins. By inhibiting NA activity, oseltamivir prevents flu viruses from spreading from infected cells to other healthy cells.

Changes in the NA proteins of a flu virus can reduce oseltamivir’s binding to them. As a result, oseltamivir’s ability to inhibit the enzyme activity of NA proteins can be diminished and this may cause “oseltamivir resistance” (non-susceptibility). A particular genetic change known as the “H275Y” mutation in the NA is the mutation that is known to confer oseltamivir resistance in A(H1N1) pdm09 flu viruses. Flu viruses that have H275Y mutation show highly reduced inhibition by oseltamivir in laboratory assays. The “H275Y’ mutation makes oseltamivir ineffective in treating illnesses with that flu virus by preventing oseltamivir from inhibiting NA activity, which then allows the virus to infect healthy cells. The H275Y mutation also reduces the effectiveness of peramivir to treat infections caused by a flu virus with this mutation. Some other mutations in the NA proteins of circulating viruses have been shown to affect the oseltamivir’s ability to inhibit the enzyme activity of their NA proteins. Such viruses can show ‘reduced’ or even ‘highly reduced’ inhibition by oseltamivir and other NA inhibitors in laboratory tests, however, not all are considered “resistant” due to insufficient data to support their drug resistance from clinical settings.

How does CDC improve monitoring of influenza viruses for reduced susceptibility and antiviral resistance?

CDC continually improves the ability to rapidly detect flu viruses with antiviral reduced susceptibility and antiviral resistance through improvements in laboratory methods; increasing the number of surveillance sites domestically and globally; and increasing the number of laboratories that can test for reduced susceptibility and antiviral resistance. Enhanced surveillance efforts have provided CDC with the capability to detect resistant viruses more quickly, and enabled CDC to monitor for changing trends over time.

How did influenza antiviral susceptibility patterns change during the previous (2019-2020) influenza season?

Antiviral susceptibility patterns changed very little in 2020-2021 compared with the previous season (2019-2020). During the 2020-2021 and 2019-2020 seasons, only a small number of viruses were resistant to oseltamivir. Most of the flu viruses tested during 2020-2021 continued to be susceptible to the antiviral drugs recommended for flu by the Centers for Disease Control and Prevention (CDC) and the Advisory Committee on Immunization Practices (ACIP) (oseltamivir, zanamivir, peramivir and baloxavir). Resistance to the adamantane class of antiviral drugs among A(H3N2) and A(H1N1) pdm09 viruses remained widespread (flu B viruses are not susceptible to adamantane drugs).

CDC conducts ongoing surveillance and testing of flu viruses for antiviral reduced susceptibility and resistance among seasonal and novel flu viruses, and guidance is updated as needed.

Because there were no dramatic changes in antiviral susceptibility patterns during the 2020-2021 flu season, the guidance for the 2021-2022 flu season on the use of flu antiviral drugs remains unchanged. The latest guidance for clinicians on the use of antiviral drugs for flu is available on the CDC web site.

What can people do to protect themselves against flu viruses with reduced susceptibility and antiviral resistance?

Getting a yearly seasonal flu vaccination is best way to reduce the risk of flu and its potentially serious complications. Flu vaccines protect against influenza A viruses of two subtypes, A(H1N1) pdm09 and A(H3N2), and type B viruses from two lineages. CDC recommends that everyone 6 months of age and older get vaccinated each year. If you are in a group at higher risk of serious flu-related complications and become ill with flu symptoms, call your doctor right away, you may benefit from early treatment with a flu antiviral drug. If you are not at higher risk, if possible, stay home from work, school and errands when you are sick. This will help prevent you from spreading your illness to others.

What implications do reduced susceptibility and antiviral resistance have for the U.S. antiviral stockpile that was created as part of the United States pandemic plan?

NAI medications can be used in the event that a novel flu A virus, such as avian flu A(H7N9) virus, gains the ability to spread easily among people in a sustained manner, and is susceptible to NAI antiviral drugs. During the 2009 H1N1 pandemic, antiviral drugs were released from the SNS and used to treat infection with the pandemic virus, now referred to as flu A(H1N1) pdm09 virus. Antivirals in the SNS are for use during public health emergencies in the United States, such as a flu pandemic, but not for seasonal flu epidemics. CDC no longer oversees the SNS.