Few Flu Cases Last Year May Mean Severe Flu Season Ahead

Once again, we face the prospect of a flu season emerging as COVID-19 grips the nation.

Flu season starts in late fall. We’re coming off a 2020-2021 season with very few flu cases, which is attributed to COVID-19 mask-wearing and social distancing precautions. A feared double whammy of COVID-19 and flu didn’t happen.

This year, it’s hard to predict how much flu will circulate and to what extend the COVID-19 Delta variant will be spreading, says infectious disease specialist Keith Armitage, MD, medical director of the UH Roe Green Center for Travel Medicine & Global Health.

There are concerns of a severe flu season ahead, based on the fact people may be more susceptible than normal. The reason is that we weren’t exposed to flu viruses last season, and immunity wanes over time, Dr. Armitage says.

“A remarkable thing that happened during the winter of the pandemic is we had virtually no influenza,” Dr. Armitage says. “It was a big upside of masking for COVID-19. The potential downside you don’t get exposed and build up immunity. Missing a year of flu might make us more vulnerable this year.”

The Flu Vaccine

All the more reason to get your flu vaccine this fall. Flu vaccines reduce the risk of flu 40 percent to 60 percent in seasons where the vaccine is well-matched to the circulating viruses, according to the U.S. Centers for Disease Control and Prevention (CDC). On top of that, vaccines significantly reduce the odds of getting severely ill for those who contract the flu.

Flu can be especially severe or deadly to elderly adults, very young children, pregnant women and people with compromised immune systems. The CDC recommends that older adults receive the flu vaccine in September and October, and that all people 6 months old and up be vaccinated.

“If you ever had full-blown flu, you don’t forget it,” Dr. Armitage says.

Avoiding the Double Whammy

Despite low flu activity last season, enough virus circulated worldwide to provide guidance on strains likely to be circulating this year, Dr. Armitage says. Flu is unlike other common viruses such as measles and chickenpox, which don’t require a new vaccine composition year to year.

The southern hemisphere flu season precedes our flu season and tells vaccine makers what strains to expect in the north. Vaccine supply and distribution is on pace, the CDC says.

Dr. Armitage says we may very well avoid a double whammy again this coming season.

“I’m hoping Delta will peak before influenza season,” he says. “And if Delta increases masking again, we’ll probably see less flu again.”