In this Thursday, Jan. 23, 2020, file photo, a patient receives an influenza vaccine in Mesquite, Texas. Credit: LM Otero / AP

Maine has seen 85 percent fewer flu cases so far this season than it’s typically seen by this point in the year, likely the result of COVID-19 mitigation measures such as masks and social distancing and indications that more people received flu shots.

There have been no hospitalizations or deaths because of influenza, pneumonia or related illnesses so far this flu season, according to weekly reports from the Maine Center for Disease Control and Prevention. From Oct. 10, 2020 — the start of the current flu season — to Jan. 9, health care providers reported only 80 cases of the flu statewide.

By this point in the year from 2016 through 2020, Maine had seen an average of 547 flu cases and 76 hospitalizations due to the flu. Last year at this time, eight people had died from the illness.

The same trend is being observed nationwide, with the U.S. Centers for Disease Control and Prevention reporting “unusually low” flu activity. From September 2020 to January 2021, only 1,103 cases were reported nationwide. That number is smaller than the number of flu cases that Maine alone had seen at this point last year: 1,287.


This flu season isn’t the first during which COVID-19 mitigation measures have kept the respiratory virus at bay.

Maine saw the same phenomenon early last spring, after Gov. Janet Mills signed her stay-at-home order in March 2020 and many businesses and gatherings stopped. Those measures slowed what had been an active flu season.

By April 2020, cumulative flu cases were still higher compared to April 2019, but the state saw significantly fewer new cases than it had in the previous year, and the number of hospitalizations dropped.

COVID-19 mitigation measures work to contain the flu because the influenza virus also spreads through respiratory droplets, like the coronavirus. In fact, those measures might appear to be more effective against the flu because COVID-19 appears to spread more easily and be more deadly, according to the U.S. CDC.

In addition to COVID-19 mitigation measures in effect throughout the country, nationwide data show that more people have received flu vaccines this year than in previous years.

Part of COVID-19’s more active spread could be because its incubation period — two to 14 days — is much longer than the incubation period of one to four days for influenza, according to Maine CDC spokesperson Robert Long and Anna Krueger, the agency’s influenza surveillance coordinator and an epidemiologist.

The incubation period is the number of days between the start of an infection and the beginning of symptoms.

Since flu symptoms show up quickly, there is a smaller window of time for people carrying the virus to spread it to others before they start feeling sick and stay at home.

COVID-19’s longer incubation period gives people more time to expose others before they start experiencing symptoms that lead them to isolate. In many cases, people who test positive for COVID-19 might not show any symptoms, which also increases the chances of transmission.

Just because flu cases are lower than normal currently does not mean the respiratory illness can’t start spreading more in the coming months, according to the Maine CDC. It’s relatively early in the flu season, and there’s a possibility that transmission will increase.

Last October, health officials expressed concern about the possibility that “two concurrent epidemics” — COVID-19 and the flu — could stretch health care providers’ ability to respond to the respiratory illnesses.

While that has not happened so far, the Maine CDC is still concerned about the state’s health care systems, which are already dealing with record numbers of COVID-19 hospitalizations, being overburdened if flu cases and hospitalizations increase.