COVID-19 vs. the Flu

Influenza (flu) and COVID-19 are both contagious respiratory illnesses, but they are caused by different viruses. COVID-19 is caused by infection with a coronavirus (called SARS-CoV-2), and flu is caused by infection with influenza viruses. Because COVID-19 is a new virus, our bodies have not experienced it and we are unlikely to have any antibodies. The virus seems to be spreading through the human population much faster than flu, and part of that has to do with the fact that all of us are susceptible. With the flu, most of us are carrying some level of antibody protection from a previous year's exposure or from a vaccine. Additionally, the case fatality rate is estimated to be 10 times higher for COVID-19 than the flu. Medical personnel are working tirelessly to learn how best to care for patients and treat COVID-19.

The CDC believes it's likely that flu viruses and the virus that causes COVID-19 will both be spreading this fall and winter. In this context, getting a flu vaccine will be more important than ever. CDC recommends that all people 6 months and older get a yearly flu vaccine.

For both COVID-19 and flu, it’s possible to spread the virus for at least 1 day before experiencing any symptoms. But, if a person has COVID-19, they may be contagious for a longer time period than if they had flu. In addition, many people with COVID-19 do not have symptoms or have mild symptoms they don’t recognize. Because they do not realize they are ill, they are more likely to spread the virus to others.

Flu and COVID-19 can both result in serious illness, including illness resulting in hospitalization or death. While there is still much to learn about COVID-19, it is more deadly than seasonal influenza. COVID-19 has claimed the lives of more than 170,000 Americans since March, shut down most major sports, closed schools, affected travel and had a devastating impact on the U.S. economy. The same cannot be said about the flu.

While the Advisory Committee on Immunization Practices has not yet voted on the flu vaccine recommendations for 2020-2021, CDC does not anticipate a major change in the recommendation on vaccination timing. Getting vaccinated in August is too early, especially for older people, because of the likelihood of reduced protection against flu infection later in the flu season. September and October are good times to get vaccinated. However, as long as flu viruses are circulating, vaccination should continue, even in January or later.

Yes. It is possible to have flu, as well as other respiratory illnesses, and COVID-19 at the same time. Health experts are still studying how common this can be. Some of the symptoms of flu and COVID-19 are similar, making it hard to tell the difference between them based on symptoms alone. Diagnostic testing can help determine if you are sick with flu or COVID-19.

Yes. CDC has developed a test that will check for A and B type seasonal flu viruses and SARS CoV-2, the virus that causes COVID-19. The test will be used by U.S. public health laboratories. Testing for these viruses at the same time will give public health officials important information about how flu and COVID-19 are spreading and what prevention steps should be taken. The test will also help public health laboratories save time and testing materials, and to possibly return test results faster.

No. The new test is designed for use at CDC-supported public health laboratories at state and local levels, where it will supplement and streamline surveillance for flu and COVID-19. The use of this specialized test will be focused on public health surveillance efforts and will not replace any COVID-19 tests currently used in commercial laboratories, hospitals, clinics and other healthcare settings. If you want to receive a test, speak to your healthcare provider.

Getting a flu vaccine will not protect against COVID-19; however, flu vaccination has many other important benefits. Flu vaccines help reduce the risk of flu illness, hospitalization and death. Getting a flu vaccine this fall will be more important than ever, not only to reduce your risk from flu but also to help conserve potentially scarce healthcare resources.

If COVID-19 symptoms persist beyond 48 hours after getting the flu vaccine, you may need a COVID-19 test. Call your healthcare provider for direction. They may also tell you to quarantine until your COVID-19 test result becomes available.