Treating Influenza (Flu)

Information for People at High Risk for Serious Flu Complications

Do you have Asthma, Chronic Obstructive Pulmonary 

Disease, Diabetes, or Heart Disease? 

If so, you are at high risk of serious illness if you get flu. Treatment with 

an influenza antiviral drug can mean the difference between having milder 

illness instead of very serious illness that could result in a hospital stay. 

This fact sheet provides information about using prescription antiviral 

drugs to treat influenza in people at high risk for serious flu complications. 

Why am I at greater risk of serious flu complications? 

Your medical condition makes it more likely that you will get complications 

from flu, like pneumonia. Flu also can make long-term health problems 

worse, even if they are well-managed. People with asthma, chronic 

obstructive pulmonary disease, or heart failure may experience worsening 

of their conditions and have difficulty breathing. Diabetes (type 1 and 2) 

can make the immune system less able to fight flu. Also, flu illness can 

raise blood sugar levels.

Can flu be treated?

Yes. There are prescription medications called “antiviral drugs” that can be used to treat influenza illness. Antiviral drugs 

fight influenza viruses in your respiratory tract. They are different from antibiotics, which fight against bacterial infections. 

What should I do if I think I have flu?

Check with your doctor promptly if you are in a group at high risk for serious complications and you get flu symptoms. 

Symptoms of flu can include fever, cough, sore throat, runny or stuffy nose, body aches, headache, chills, and fatigue. 

If you get flu, antiviral drugs are a treatment option. 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 vaccines can vary in how they work, flu 

vaccination is the first and best way to prevent influenza. You should receive flu vaccine every year. Antiviral drugs are 

a second line of defense to treat flu if you get sick.

What are the benefits of antiviral drugs?

Antiviral treatment works best when started within two days of getting symptoms. Antiviral drugs can lessen fever and 

other symptoms and shorten the time you are sick by about one day. They also can prevent serious flu complications, 

like pneumonia when treatment is started early.

For people at high risk of serious flu complications, early treatment with an antiviral drug can mean the difference 

between having a milder illness instead of a more serious illness that could result in a hospital stay. For adults 

hospitalized with flu illness, some studies have reported that early antiviral treatment can reduce the risk of death.

What antiviral drugs are recommended?

There are four FDA-approved influenza antiviral drugs recommended by CDC: oseltamivir (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®). Oseltamivir is available as a pill or liquid, and zanamivir is a powder that is inhaled. 

Peramivir is administered intravenously by a health care provider. Baloxavir is a pill given as a single dose by mouth. 
What are the possible side effects of antiviral drugs?

Side effects vary for each medication. For example, the most common 

side effects for oseltamivir are nausea and vomiting, zanamivir can 

cause wheezing and difficulty breathing (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. 

When should antiviral drugs be taken for treatment?

Studies show that flu antiviral drugs work best for treatment when 

started within two days of getting sick. However, starting them later 

can still be helpful, especially if the sick person is in a group at high 

risk for serious complications (see list in sidebar) or is very sick from 

flu (for example, hospitalized from flu). Follow your health care 

provider’s instructions for taking these drugs. These antiviral drugs 

are given in different ways and are approved for different ages.

How long should antiviral drugs be taken?

To treat flu, oseltamivir and zanamivir are usually taken for 5 days, 

although people hospitalized with flu may need the medicine for 

longer than 5 days. Peramivir is given once intravenously. Baloxavir is 

given as a single dose. 

Can children take antiviral drugs?

Yes. Oseltamivir is recommended by CDC and the American Academy 

of Pediatrics (AAP) for early treatment of flu in people of any age, and 

for the prevention of flu (i.e., prophylaxis) in people 3 months and older. 

Zanamivir is recommended for early treatment of flu in people 7 years 

and older, and for the prevention of flu in people 5 years and older. 

Peramivir is recommended for early treatment in people 2 years and 

older. Baloxavir is recommended for early treatment of flu in people 12 

years and older. 

Can pregnant and breastfeeding women take antiviral 

drugs?

Oral oseltamivir is recommended for treatment of pregnant women it has 

the most studies available to suggest that it is safe and beneficial during 

pregnancy. Baloxavir is not recommended for pregnant women 

or breastfeeding mothers. 

Who should take antiviral drugs? 

It’s very important that antiviral drugs be used early to treat flu in people 

who are very sick with flu (for example, people who are in the hospital).

People who are sick with flu and have a high-risk factor related to a 

health condition like asthma, diabetes or chronic heart disease or their 

age. (See the full list of high-risk factors).

Health and age factors known 

to increase a person’s risk for 

developing flu-related complications:

• Asthma

• Neurological and neurodevelopmental 

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 or medication (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 high risk from

the 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 high 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.younger than 6 months old.

For more information, visit: www.cdc.gov/flu

or call 1-800-CDC-INFO

CS HCVG-15-FLU-101 September 11, 2020