Cause

Different types (strains) of flu viruses that spread each year

A type of coronavirus called SARS-CoV-2. Different strains of SARS-CoV-2 have spread since the pandemic started in 2019.

How it spreads

It spreads from person to person through coughing, sneezing, talking, or touching infected surfaces and touching your eyes, nose, or mouth

It spreads from person to person through coughing, sneezing, talking, or touching infected surfaces and touching your eyes, nose, or mouth. Current research shows that it spreads more easily than the flu, but not as easily as measles.

Prevention

Wash your hands often, stay home if you feel ill, limit contact with other people, and avoid people who are sick.

Wash your hands often, stay home if you feel ill, limit contact with other people, and avoid people who are sick. Wear a face mask when around other people. Follow your healthcare provider's guidance on vaccines and booster shots.

Vaccine

Different types of flu vaccines are available each year. Getting a vaccine can help prevent or lessen symptoms of the flu. Talk with your healthcare provider about the type of vaccine that’s best for you and when to get it. If you are sick with any infection, get the flu vaccine as soon as you recover.

Several vaccines are available to prevent COVID-19, including in those who are pregnant or breastfeeding. COVID-19 vaccines are advised for everyone ages 6 months and older. 

Booster shots are also advised to help build up better immunity to fight the virus. Boosters also lower the risk for serious illness and death from COVID-19. Booster shots are available and advised for people ages 6 months and older. Talk with your healthcare provider about which vaccine and booster are best for you and your family.

Symptoms

They can be mild to severe, and can include:

• Fever

• Chills

• Body aches

• Cough

• Sore throat

• Stuffy or runny nose

• Headache

• Tiredness

• Vomiting and diarrhea, more often in children

Some people have no symptoms. In other people, they can be mild to severe, and can include:

• Fever

• Chills

• Body aches

• Cough

• Sore throat

• Stuffy or runny nose

• Headache

• Tiredness

• Feeling short of breath

• New loss of taste or smell

• Nausea

• Vomiting

• Diarrhea

When symptoms start

Usually 1 to 4 days after infection

Usually 2 to 5 days after infection, but can start 2 to 14 days after infection

How long a person is contagious

A person can spread the flu at least 1 day before symptoms start. Older kids and adults are most contagious for the first 3 to 4 days of symptoms. They can spread the virus up to 7 days after symptoms start. Babies and people with weak immune systems can be contagious longer

How long someone can spread the virus that causes COVID-19 is still being studied. On average, a person can start spreading the virus about 2 to 3 days before symptoms start. But they are most infectious 1 day before symptoms start. Most people can keep spreading the virus for 8 more days after symptoms start.

Testing

There are different kinds of rapid flu tests. The tests are done by wiping a swab inside your nose or throat. The results can come back in 10 minutes to several hours. A saliva-based test is being developed.

A  single test for both flu and SARS CoV-2 may be available. Talk with your healthcare provider to learn more.

There are different kinds of tests for COVID-19. Some check for a current (active) infection. This is called a viral test. Other tests check for a past COVID-19 infection. This is called an antibody test. These are done by a healthcare provider or lab.

Rapid viral tests, including self test kits, are available to check for an active infection. Free at-home COVID-19 tests are available at www.covid.gov/tests. Other tests for active infection may be done by a lab. Some are rapid tests with results ready in minutes. Others may take a few days to get the results

Treatment

The flu may be treated with antiviral medicine. This can help ease symptoms. It can also shorten the amount of time you’re sick. These medicines need to be taken as soon as possible when you start to feel sick. Antibiotics are not used because they don’t work on the flu virus. But antibiotics may be used to prevent or treat an infection by bacteria that can sometimes happen after having the flu. Other treatment for the flu includes care to ease symptoms. This includes rest, drinking plenty of fluids, and pain and fever medicine as needed. In severe cases, you may need time in the hospital to treat complications from flu.

Treatment for COVID-19 generally includes care to ease symptoms. This includes rest, drinking plenty of fluids, and pain and fever medicine as needed. For mild illness, you may need antiviral medicines, steroids, or antibody therapies. In severe cases, you may need time in the hospital for supplemental oxygen, IV fluids, and other care.

Treatments are available for people who are at high risk of getting severe COVID-19 and being admitted to the hospital. Treatments must be started within a few days after you develop symptoms, so don't delay calling your healthcare provider. Check Test to Treat location to find a testing location in your area.

Antibiotics are not used because they don’t work on the virus that causes COVID-19. But antibiotics may be used to treat an infection by bacteria that may happen after getting COVID-19.

Possible complications

Can include:

• Bacterial infections

• Ear infection

• Inflammation of muscle tissues (myositis or rhabdomyolysis)

• Inflammation of the brain (encephalitis)

• Inflammation of the heart (myocarditis)

• Multiple-organ failure

• Pneumonia

• Sepsis

• Sinus infection

• Worsening of chronic conditions of the lungs, heart, and nervous system

• Worsening of diabetes

Can include:

• Acute respiratory distress syndrome (ARDS)

• Bacterial infections

• Heart attack

• Inflammation of muscle tissues (myositis or rhabdomyolysis)

• Inflammation of the brain (encephalitis)

• Inflammation of the heart (myocarditis)

• Ongoing problems with taste or smell

• Memory and concentration problems, also called "brain fog"

• Multiple-organ failure

• Pneumonia

• Respiratory failure

• Sepsis

• Stroke

• Worsening of chronic conditions of the lungs, heart, and nervous system

• Worsening of diabetes

• Multisystem inflammatory syndrome in children (MIS-C), a rare complication that causes inflammation of blood vessels and organs. Multisystem inflammatory syndrome in adults (MIS-A) has been reported but is rare.