Flu Vaccine No Match for Circulating Variants This Season

FRIDAY, March 11, 2022 (HealthDay News) -- This season's flu shot offered virtually no protection against infection, a new government report shows.

While this latest vaccine only cut the risk of getting a mild case of flu by 16%, the agency has noted that flu vaccines typically reduce the risk of illness by 40% to 60%.

Still, the shot should offer some protection against more severe illness, according to the study from the U.S. Centers for Disease Control and Prevention.

But the findings mean the flu vaccine was “essentially ineffective,” Dr. William Schaffner, an infectious diseases expert at the Vanderbilt University Medical Center in Nashville, Tenn., told NBC News.

The CDC study, which included data on over 3,600 Americans in seven states, confirmed research released earlier in the flu season that the dominant variants is H3N2, which is particularly challenging to guard against because it tends to mutate faster than other flu variants and often results in more hospitalizations and deaths, according to experts.

In October and November of 2021, the CDC investigated a flu outbreak at the University of Michigan and found that the vaccine did not offer much protection.

Despite the vaccine's meager level of protection, this flu season has been the second in a row to show low overall case counts. That may be because the surge of the Omicron variant in December and January had people wearing masks and practicing social distancing, thereby preventing the spread of the flu, Schaffner suggested.

He added that the latest CDC study highlights the need for better flu vaccines because "the flu is not going away. ... It will be back again next year and the year after that and the year after that."

Not only that, even a mild flu season can be deadly: The CDC has estimated that during the 2019-20 flu season, around 22,000 people in the country died and 400,000 were hospitalized.

A number of vaccine makers including Pfizer and Moderna, are trying to develop flu vaccines using mRNA technology, the same approach used to create some COVID-19 vaccines. But those vaccines likely won't be ready until late 2023, NBC News reported.

More information

Visit the U.S. Centers for Disease Control and Prevention for more on the flu.