- Flu vaccination helps protect against severe illness and hospitalization.
- The flu shot is formulated months in advance based on research of potential strains.
- The CDC has announced that this year’s vaccine seems to be a “very good match” to circulating strains.
Officials from the U.S. Centers for Disease Control and Prevention (CDC) announced that the formulations of the flu shot this year are a good match for the current viral strains circulating in the country.
The news comes as flu cases have risen drastically in recent weeks.
It’s estimated that up to 11% of Americans catch the flu virus each year — with some experiencing more severe symptoms and requiring hospitalization.
“The composition of flu vaccines is reviewed annually by the Centers for Disease Control and Prevention (CDC),” explained Bernadette Boden-Albala, DrPh, director and founding dean of the Program in Public Health at the University of California, Irvine.
“Vaccines are updated to protect against the viruses that research indicates will be most common during the upcoming flu season,” Boden-Albala told Healthline.
Despite the potential for virus ‘mismatch’, the CDC announced this week that this year’s vaccine seemingly aligns with the circulating strains.
The vaccine targets more than just one type of flu virus. “All flu vaccines in the United States are ‘quadrivalent’ vaccines, which means they protect against four different flu viruses,” said Boden-Albala.
The four viruses are:
- Influenza A(H1N1) virus
- Influenza A(H3N2) virus
- Two influenza B viruses
In recent years, the flu shot has
However, year-to-year, that level has ranged widely: from 60% in the 2010-2011 flu season to 19% in the 2014-2015 flu season.
As the flu season progresses, experts will continue to get more information about the most common circulating strains.
“Estimates for the 2022-23 flu season will continue to update through the rest of the year,” stated Boden-Albala. After this, “the CDC will produce a report on vaccine effectiveness.”
Experts say the flu shot can also help lessen symptoms for people who end up developing the disease.
When formulating flu shots, experts look at countries in the southern hemisphere to see what strains are circulating during their winter.
For instance, the
However, “the reliability of this approach is debatable,” Matt Weissenbach, DrPH, senior director of clinical affairs at Wolters Kluwer Health, shared with Healthline.
This is primarily because it doesn’t take into consideration “confounding variables and limitations, such as missing data or external factors that couldn’t be controlled.”
That said, Weissenbach continued, “it’s still a worthwhile exercise when examining projections for overall incidence, timing, and season duration.”
By the third week of November, nearly
It takes about two weeks following vaccination for protective antibodies to develop in our immune systems, Boden-Albala explained. However, these antibodies don’t last forever — which is another reason why it’s advised to get a flu shot each year.
Numerous studies have explored how effectively flu vaccines protect against the virus. The CDC
Meanwhile, in Chile earlier this year, vaccination was
Boden-Albala shared that epidemiologists have predicted the upcoming flu season might be ‘bad’. This is partly because one of the main strains expected to circulate is linked to more severe symptoms.
But another reason more people could be impacted? The after-effects of pandemic-related measures, such as mask-wearing, social distancing, and staying at home.
“Community mitigation measures implemented throughout the pandemic are thought to have influenced influenza virus transmission to some degree,” stated Weissenbach.
Furthermore, Boden-Albala explained, these actions “have limited [our] exposure in the last few years to flu.” As such, “it’s expected that flu may be worse because of lower levels of circulating antibodies.”
The government has