Following a virtually nonexistent flu season in 2020-2021, health officials are voicing concern that the 2021-22 season is shaping up to be significantly worse—which could cause a "twindemic," Felicia Schwartz writes for the Wall Street Journal.

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Why this flu season may be worse than the last

According to Schwartz, physicians and researchers predict this flu season could strike earlier and be more severe than usual. This is partly because many people are still social distancing and working from home, which has kept them from building up their natural immune defenses. Moreover, as Covid-19 restrictions continue to ease, people will lose the added protection gained through practices such as social distancing, wearing masks, and heightened cleaning protocols.

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For instance, most schools have returned to in-person learning, which comes with a higher chance of infection and transmission of both the flu and Covid-19. And further exacerbating the issue, health care experts expressed concern that people may be resistant to the flu vaccine after receiving their Covid-19 shots, or they may just skip the flu vaccine altogether—especially if they continue to work from home and traditionally received the flu vaccine through work.

Lack of data

Experts are also concerned that the flu strains selected for this year's flu vaccine may not be as accurate as previous years, since so little flu circulated in the 2020-2021 flu season, Schwartz reports.

For context, according to Schwartz, the World Health Organization each year analyzes data from the previous flu season to select the annual flu strains. FDA then chooses the strains used in the flu shot in the United States.

According to CDC, a typical flu season in the United States sees anywhere from 9 million to 45 million infections, which leads to 140,000 to 810,000 hospitalizations and 12,000 to 61,000 deaths, most of them in adults 65 and older. But the hospitalization rate for the 2020-2021 flu season in the United States was just 0.7 per 100,000 people—the lowest since the agency started tracking flu data in 2005. 

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As a result, according to Richard Zimmerman, a professor at the University of Pittsburgh and a former chair of a U.S. government flu advisory panel, this year's "educated predictions had a lot less data to be based on in the strain selection committee"—which could result in a less accurate vaccine. Zimmerman's model predicts that this flu season will yield 102,000 more infections than last season if the vaccine is not highly effective and people's uptake of the flu vaccine remains low. 

'Twindemic' overload

In particular, according to Schwartz, health experts are concerned about the potential of a "twindemic," with rates of both Covid-19 and flu overwhelming health care resources.

For instance, William Schaffner, professor of preventive medicine at Vanderbilt University School of Medicine, said that our "worst case scenario is a real twindemic" of Covid-19 and an influenza outbreak. 

"Influenza is a very tricky little devil, it's very evasive," said Elaine O'Hara, head of Sanofi's North America vaccine business. "The last thing we want is outbreaks with respect to Covid or influenza because you don’t want both of those happening at the same time."

Efforts to encourage vaccination

In response to this potential scenario, CDC is encouraging people to get the flu shot via a planned digital campaign. In addition, the agency has also allocated more than $150 million to support national, state, and local campaigns directed at bolstering public confidence in vaccines for Covid-19 and influenza among racial and ethnic minority populations.

Meanwhile, pharmaceutical companies, including AstraZeneca, GlaxoSmithKline, and Sanofi, are supplying between 188 million and 200 million flu vaccines to the United States this year, according to CDC. The number of supplies would be on par with last year's shipment, Schwartz writes, which were a record high. 

GlaxoSmithKline and Sanofi are also launching public-awareness campaigns to increase vaccination rates this season, with Sanofi also debuting an online tool for health care providers to encourage people to come into a doctor's office to get vaccinated after many skipped the shot to stay home during the prior flu season. In late August, AstraZeneca made its nasal spray flu vaccine available to people ages 2 to 49, which could help expand access to the vaccine, Schwartz reports. (Schwartz, Wall Street Journal, 9/9)