Federal data shows that flu activity is currently “unusually low,” diminishing – but not eliminating – fears that a severe flu season combined with the coronavirus pandemic could lead to a “twindemic.”
As the weeks ticked through the fall and into January, experts waited for the flu cases to come. The Centers for Disease Control and Prevention has documented over 1,100 cases of the flu so far. While some mild cases are likely going undiagnosed, nearly every state is experiencing “minimal” flu activity, according to the agency.
“It’s a rare bright spot in what is otherwise a really challenging time,” says Lisa Maragakis, the senior director of infection prevention for the Johns Hopkins Health System.
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Just 136 people were hospitalized with the flu from Oct. 1, 2020, through mid-January, compared to nearly 5,800 at this time last year, according to the CDC. The agency documented over 290 deaths involving influenza in the same timeframe, while last flu season claimed a total of roughly 22,000 lives. Fear that flu hospitalizations on top of the coronavirus pandemic would inundate health care systems led experts to warn of a possible “twindemic.”
A typical flu season peaks between December and February. According to CDC data, visits to health care providers for influenza-like illnesses are far under the national baseline and comparable to the 2011-2012 season, which set a record for the smallest and shortest seasonal peak. The agency cautions that the data could be affected by the pandemic.
“I think it’s clear that we have drastically lowered the flu transmission really around the world this year,” Maragakis says. “It’s remarkable.”
Influenza, like the coronavirus, is a respiratory virus, so the mitigation measures for COVID-19 – hand washing, mask wearing and social distancing – also work for the flu. But with transmission of the coronavirus remaining high – at an average of 164,000 new cases per day – how could the flu numbers be so low?
Chief epidemiology officer at the University of Florida Health Shands Hospital Nicole Iovine says that while the measures have not been enough to control the coronavirus, they are likely playing a major role in keeping flu numbers low because it is less transmissible. She adds that it looks like this flu season could have been mild anyway.
“I think that we lucked out that this year was destined to be a relatively mild flu season and then, given that we have all these mitigation measures, that really gave it an additive effect of further mitigating the impact of the flu,” Iovine says.
A person sick with the coronavirus is likely to spread the virus to over two people. For the flu, the attack rate is typically above one, though each season is different.
“Maybe that doesn’t sound like a lot, but when you talk about millions of people, all that starts adding up,” Iovine says.
The effort could also be assisted by a high level of flu vaccine use. The CDC distributed over 193 million doses of the flu vaccine as of mid-January, which is the highest number for a single season.
Still, experts warn that the flu season can be unpredictable and that the U.S. is not out of the woods yet. Since 1982, six flu seasons have peaked in March, according to the CDC.
“Anything kind of goes when it comes to the flu,” Iovine says.
Maragakis warns that relaxing coronavirus mitigation measures later in the winter could result in a surge of flu.