With all the coverage and attention on COVID-19, the flu seems to have disappeared. In fact, the CDC says the flu has decreased by 98% in the United States.  How is this possible?  With the rate of COVID-19 increasing and a similar transmission, why is one up and the other down?

To understand the reason for the reduction, we must first understand the flu. Influenza (flu) is a contagious, mild-to-severe respiratory illness caused by Influenza viruses. The two main types are A and B, which are responsible for the seasonal flu epidemics each year. Even though the flu virus can be found year-round, in the northern hemisphere the flu season is greatest during the fall and winter, with the United States peaking in the months of December and February.

Flu transmission is very similar to how COVID-19 is spread. It circulates in respiratory droplets when people infected with the flu cough, sneeze, or talk. These droplets land in the mouth and noses of people who are nearby and are inhaled into the lungs.   Once infected with the virus, a healthy adult is contagious starting from the day prior to symptoms starting and up to 7 days after. The first 3-4 days are considered the most contagious.

Now, I know you are reading on thinking, “the flu and COVID-19 seem so similar, why are the cases for the flu down and COVID-19 increasing?  They are the same thing, right?”  Unfortunately, this is a common misconception. Though they are both transmitted in the same manor with similar symptoms, there are differences between the two viruses. First, they are caused by 2 different viruses. COVID-19 can spread more easily and quickly in groups than the flu and can cause a more severe infection and complications after the illness subsides.

In the beginning of the COVID-19 pandemic, the flu numbers decreased due to the lack of testing, because if a person had a respiratory illness, they were automatically sent for COVID-19 testing rather than the flu. Many infectious disease experts say it is hard to pinpoint the exact reasons why the flu cases are low, but per the CDC, the main idea is the mitigation efforts we are using to slow the spread of COVID-19. Children play a major role in the spread of the flu. With schools being currently out and social distancing being practiced, in addition to increased handwashing and mask wearing, the children are not becoming infected. Therefore, they are not bringing it home and spreading inside the family. In addition, the community mitigation measures and vaccinations are also likely reasons for reducing incidents.

Though 2020 was a very difficult year, we learned a great deal regarding the spread of illness within the community.  This knowledge is very important, because understanding how these efforts work can change the way we proceed with the flu in the future.   Changing efforts helps to decrease severe illness and protect our most vulnerable.