Forecasts for a severe flu (influenza) season are ubiquitous. Concerns that a high rate of flu coupled with COVID-19 infections can send more people to emergency rooms and fill hospital beds at record rates. Perhaps such forecasts are not seeing the complete picture.
Making forecasts with a paucity of reliable data is guaranteed to provide murky insights at best.
The 2020-2021 flu season never got off the ground, largely due to people physically distancing from each other and wearing face coverings. These nonmedical countermeasures, designed to slow the spread of the coronavirus, were equally effective in keeping the flu in check.
Fast forward to this year, with more people out and many returning to in-person work and socializing, opportunities to spread the flu are abundant.
The fear is that with both the coronavirus and the flu virus circulating, a person who develops respiratory symptoms may be unable to distinguish between the two. Such a convolution of infections could create surges in demand on medical resources. Human nature is such that when presented with multiple options, caution urges us to select the worst-case scenario, which in this case would be COVID-19.
However, this assumes that all precautions to protect ourselves against COVID-19 will be abandoned, which is unlikely over the next six months.
Those most vulnerable to severe outcomes with seasonal flu are those over 65 years of age, the same group that is most vulnerable to COVID-19. This group has already been highly receptive to the COVID-19 vaccines, with over 94 percent having received at least one dose. This group will likely also get the flu vaccine with the high dose formulation, hence will have protection against both viruses.
Those under 5 years of age are also vulnerable to the seasonal flu. Given that they will be ineligible for COVID-19 vaccines, having them vaccinated with the flu vaccine should be a priority.
Credit: UI Public Affairs: L. Brian Stau
Credit: UI Public Affairs: L. Brian Stau
Among those 6 to 64 years of age, getting the flu vaccine makes sense. Those in this cohort that have received the COVID-19 vaccine (those over 12 years old) will also be receptive to the flu vaccine. Given that the U.S. government provides a production safety net for the flu vaccine manufacturers, supply will not to be an issue. Based on prior year supply data, around 200 million dose should be available.
What remains unknown, the wild card for the seasonal flu, is people’s behavior.
If people abandon all physical distancing and wearing face coverings in congested public areas, then the worst case scenario for COVID-19 and seasonal flu could occur. What will suppress the hospitalization numbers are how well people are vaccinated against both.
Given that booster COVID-19 shots are now beginning to be rolled out, will the third dose also protect more effectively against infections, not just hospitalizations and deaths? It is too early to assess if this will be the case, but if it turns out to be what occurs, the path forward will be smoother and swifter.
The takeaway from this analysis is that everyone can and will contribute to whether we have a mild or severe flu season. The choices that people make, and the precautions that people take, will determine the severity of the season. These behaviors are within each of our control.
What we cannot control is which variants of the influenza virus will circulate and be dominant, and will they match with the antigens selected for this year’s flu vaccines, which are set as much as nine months in advance. Over the five flu seasons from 2015 to 2020, the flu vaccines have been between 29 and 48 percent effective. At such levels, their effectiveness reduces hospitalizations and deaths.
So will this flu season be severe? It does not have to be.
Sheldon H. Jacobson, Ph.D., is a founder professor of computer science at the University of Illinois at Urbana-Champaign. He applies his expertise in data-driven, risk-based assessment to evaluate and inform public policy.
About the Author
