UMass Chan infectious disease experts explain multiple factors behind flu season concerns
The worldwide spread of influenza came to a screeching halt in March 2020, when schools, businesses and daily life shut down because of the COVID-19 pandemic. But it is expected to come back strongly this fall and winter, making flu vaccination more essential than ever.
“Every infectious disease specialist I know is expecting flu to return,” said infectious disease specialist Richard T. Ellison III, MD, professor of medicine and hospital epidemiologist at UMass Memorial Medical Center. “There is likely much less immunity to flu this year as no one was exposed to it, and many people may not have gotten the flu vaccine last year.”
Dr. Ellison explained that global transmission of the virus was interrupted in 2020 when people stopped traveling and most locales were shutdown.
“No one saw any significant cases of influenza. They went from thousands of cases a week down to 20 or so per week,” he said, pointing to World Health Organization data.
Now that people are out and about, traveling more and wearing masks less, experts anticipate a resurgence of several infectious diseases, including the flu.
Typically, influenza causes between 12,000 and 50,000 deaths per year in the United States, according to estimates from the Centers for Disease Control and Prevention. Many more become sick and require hospitalization.
The widespread prevalence of COVID-19 infection already in the population – resulting so far in more than 700,000 deaths nationwide – makes the risk of influenza infection even more serious, Ellison said.
“Because both viruses are spreading, it is quite possible somebody could get a double whammy and get both at the same time,” he said. “Having COVID is much more serious than having the flu but having both is probably worse than either by themselves.”
The COVID-19 vaccine does not protect against the flu because the diseases involve different viruses. Similarly, there is no potentially harmful interaction between the COVID-19 vaccine and the flu vaccine.
“It’s possible to get both vaccines at the same time,” said Ellison, “with the only downside of a bigger risk of a sore arm from getting two shots on the same day.”
Ellison said the hospital laboratory is gearing up to test patients who come in with symptoms for both influenza and COVID-19.
Jennifer Wang, MD, professor of medicine, agreed that there is potential for a worse flu season than usual “because we missed last season and there is less immunity in the community.” Plus, with students back in school, they may be bringing home the influenza virus, which could then infect older, more vulnerable relatives.
“So now there are going to be two reasons to be wearing masks, doing the social distancing and not going out in large groups, which remains high risk for both flu and COVID,” Ellison said. “Anything you do to protect yourself against COVID is clearly helpful in protecting against the flu. Those things are all worth doing, on top of getting the vaccines.”