If you’re collecting small silver linings in this terrible, horrible, no good, very bad year, here’s another one for you: In Massachusetts, there's been almost no flu season.
“This low degree of flu activity is unprecedented,” said Dr. Paul Sax, the clinical director of the Division of Infectious Diseases at Brigham and Women's Hospital and a professor at Harvard Medical School.
“And it's really fortunate, because one of the things we were all very terrified about was that when COVID-19 came back seasonally, as we predicted it would in the winter, we thought we'd have a dual occurrence of both COVID-19 and influenza," Sax said. "And thank goodness it didn't happen.”
The last weekly influenza update from the state Department of Public Health, issued March 19, showed flu-related hospitalizations bumping along close to zero since the end of September — far below the mid-winter spikes of around 5% and 3% during the last two flu seasons.
Last year was a particularly severe season, with two spikes, the larger of which came at the beginning of April. But this season had hardly any rise in cases to speak of, according to the DPH update.
Sax said many people did get flu shots this season, but there's more to it than that. The flu season that really wasn’t is teaching experts something about how flu is transmitted.
Infectious disease specialists theorize that, like the coronavirus, flu can be spread not just by larger droplets that fall out of the air quickly but also by smaller aerosols that linger in the air longer.
“We've done a lot to eliminate aerosol transmission by just staying out of crowds and wearing masks," Sax said. “The other interesting theory is that [the historically low flu rates] have to do with schools being closed. Influenza, as you may know, is very much a disease of children. And, in fact, children get the flu at much higher rates than adults.”
Sax said there’s a third theory to explain what happened this flu season that says travel is required for flu.
“We kind of import our flu from other countries, in particular from other hemispheres," the theory goes, according to Sax. "And that's how flu gets started."
"So [there are] a bunch of different reasons," he added. "I don't think anyone knows exactly which one is the most important, but we have way fewer cases than ever. And thank goodness.”
Still, Sax doesn’t see this year’s flu season as a harbinger of less severe flu seasons in the future.
"Remember, influenza has enormous animal reservoirs, and so flu is coming back," he said. "The question is whether the infection control measures we put in place for travelers can somehow keep it at bay. I am concerned, of course, that the biggest vectors in the flu are children. And once children go back to school and daycare, we're going to see the flu again."
