Poor immunity, vaccine efficacy may lead to rough flu season

by Jacob Fuller

Lauren Dempsey, MS in Biomedicine and Law, RN, FISM News


The U.S. has had remarkably mild flu seasons over the last two years, according to preliminary data from the Centers for Disease Control and Prevention.

Some health experts had feared that there would be a “twindemic” with flu and COVID-19 both circulating simultaneously. There was concern that such an overlap of activity from both viruses would be overwhelming and potentially catastrophic for the U.S. and the world.

That prediction never came true. The CDC claims that COVID-19 mitigation strategies greatly reduced, and nearly eradicated the flu virus in the last two years, using historically low numbers to justify their presumption.

Now that the CDC is relaxing COVID-19 prevention for the general public, experts are warning that this year’s flu season could be worse than ever.

According to the CDC, the best prevention is vaccination, which they recommend for everyone aged 6 months and older. However, according to CDC-backed research, the effectiveness of flu shots varies wildly from one season to the next, based on who is taking the vaccine and how well the vaccine matches whatever flu strain is circulating that season.

Other CDC recommendations for avoiding the flu include avoiding others when sick, covering coughs and sneezes, practicing good hand hygiene, and avoiding touching your face.

Since October of 2021, there have been 133,801 positive cases with 98.4% being influenza type A. Nearly all recently reported cases have been some form of influenza A(H3N2). According to the CDC, “current flu vaccines tend to work better against influenza B and influenza A(H1N1) viruses and offer lower protection against influenza A(H3N2) viruses.”

CDC estimates show the vaccine was only 14% effective during the 2021-2022 season.

Preliminary data from the 2019-2020 season estimates that there were 35 million symptomatic infections, 16 million medical visits, 380,000 hospitalizations, and 20,000 deaths in the last year before the COVID pandemic.

Flu season typically begins in October, peaks in the winter months, and lasts through May. Data from the Department of Health and Aged Care out of Australia suggests that the upcoming season could start earlier and may have a greater impact on children and older adults.

Australia’s flu report shows children between the ages of 5 and 9 have had the highest rate of flu cases this year, followed by kids under 4, and adolescents.

Some experts are concerned that this may be a sign of a stronger virus or that the population is less protected because people haven’t been exposed over the last two seasons. A big factor in fighting the flu is immunity, which requires exposure. While COVID-19 mitigation measures may have helped prevent the spread of flu, they also may have caused a decrease in natural human immunity.

“The overall immunity in the population is relatively low – particularly in the younger age groups,” said Andy Pekosz, a virologist at the Johns Hopkins Bloomberg School of Public Health, told USA Today. “That’s also supported by the fact that usually when we see an early flu season, that means there’s not a lot of immunity in the population.”

The flu places a significant disease burden on the U.S. population each year. Each season is different, however. Forecasting predictions for flu activity can help implement strategies to keep the public safe, but the severity and timing of flu season are difficult, if not impossible, to accurately predict.

Common flu symptoms are fever, cough, sore throat, congestion, muscle aches, headaches, fatigue, vomiting, and diarrhea. Treatment usually includes antiviral medications and/or symptom management. Those most at risk are adults aged 65 and older, individuals with chronic health conditions, young children, and pregnant women.

Additional edits and reporting by Jacob Fuller, FISM News.

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