How Long Does Flu Last, Treatments Explained As Cases at Pre-COVID Levels

Flu activity in the U.S. is increasing according to the Centers for Disease Control and Prevention (CDC), even as COVID cases driven by the Omicron variant continue to rise.

The flu is a highly transmissible respiratory illness caused by a range of influenza viruses. The three influenza virus types are A, B, and C. They spread between people via droplets, such as when sick people cough or sneeze. Flu can also be spread via saliva.

For most healthy people, the flu is an unpleasant but short-term illness that resolves itself as the immune system fights it, according to Harvard Medical School. It is not the same as the common cold, which tends to be less severe and is caused by a different group of viruses.

Symptoms of flu may include aches and headaches, chills, fever, cough, vomiting, sore throat, diarrhea and fatigue.

How long these symptoms last can vary between people, but they usually last between five and seven days and start between one and four days after someone has been exposed to the virus, Harvard Medical School says. Symptoms may not last as long if someone has had the flu shot.

Scotland's national health information service, NHS Inform, similarly states that people who catch the flu "usually begin to feel better within about a week."

In cases where people are particularly sick with flu or are in a higher risk group, doctors may prescribe antiviral drugs. These can make the illness milder and shorten the length of the illness.

Otherwise, Harvard Medical School states that people with the flu should rest, drink plenty of fluids, and take pain relievers.

The CDC's flu tracker states that a total of 242 lab-confirmed flu-related hospitalizations were reported by states and counties participating in the FluSurv-NET network between October 1 and December 11, which is more than the total number of hospitalizations reported during the 2020-2021 season and similar to those seen in the 2015-2016 season.

The total number of patients admitted to hospitals with flu is much higher, however. According to the HHS-Protect surveillance network, 1,057 patients were admitted to hospitals with flu in the week ending December 11 alone.

According to The New York Times analysis of CDC data, the total number of flu cases nationwide in the U.S. in the week ending December 11 was at a level not seen since before the coronavirus pandemic.

Flu activity is particularly increasing in eastern and central parts of the country, the CDC said, with the western part of the country reporting lower levels of circulation according to the most recent analysis.

The CDC said it is not too late to get vaccinated against the flu, despite the fact that people typically get the flu shot ahead of the season.

The rise in flu cases means that both flu and COVID-19 are spreading around the U.S. at the moment.

According to the CDC, the symptoms of the flu, COVID, and other respiratory diseases can be similar and a test may be needed to tell the diseases apart. However, COVID seems to cause more serious symptoms than flu in some people and hospitalization and death can occur even in healthy individuals. It can also cause people to be contagious for longer.

People can be infected with both COVID and the flu at the same time and have symptoms of both.

Woman blowing nose
A stock photo shows a woman blowing her nose. Flu cases are spreading in the U.S., the CDC has said this month. Ridofranz/Getty