This winter’s influenza vaccine was particularly inconsistent with the most common influenza strains in circulation. This is due to a new analysis by the US Centers for Disease Control and Prevention. Thankfully, the flu season has been much milder than usual for the second year in a row. This is likely because continued covid-19 precautions have also slowed the spread of influenza.
Estimates are obtained from the CDC’s long-term monitoring program for people with suspected influenza-like symptoms who visit various outpatient sites across the country. Overall, the researchers found that the chances of catching a confirmed case of influenza were only slightly lower in vaccinated people. The vaccine is 14% effective against all influenza strains detected at these sites and is also 16% effective in preventing influenza from the main strain A (H3N2) virus this winter. Was considered. This low number is well below the 50% threshold for vaccines to be considered relatively useful and not high enough to reach statistical significance.
In the words of a researcher Release Their results in a weekly report on CDC morbidity and mortality show that the vaccine “did not reduce the risk of outpatient respiratory disease caused by the influenza A (H3N2) virus, which had been predominant this season.”
Influenza vaccines are far from perfect, even in good years. Influenza virus strains that infect humans are constantly evolving.In other words, scientists Try to predict What will these strains look like during the next flu season to match the strains contained in the vaccine (vaccines usually contain 4 strains at a time). Vaccines are often about 50% to 60% effective in this guessing game, but mismatches can be exacerbated, as this year.It doesn’t help that this year’s main flu is H3N2, a subtype of flu Already known Because it is more difficult to predict than others.
The lucky break this winter is that the flu has stopped again. Cases, hospitalizations, and deaths tend to be historical, but not as low as in the winter flu season of 2020-2021. (These numbers were so small that the CDC couldn’t even estimate the effectiveness of the vaccine for the season.) Minority The cases seen in the previous season were probably made predict This year’s flu season will be even tougher. The Gentle Influenza in the last two seasons has resulted from public health measures aimed at delaying the transmission of the much more contagious SARS-CoV-2, including regular wearing of masks.
Last month, World Health Organization issued The recommendations for influenza vaccines for next winter in the Northern Hemisphere included calling for a renewal of the H3N2 strain used as a reference. However, the CDC authors state that “it is still difficult to predict virus subtypes and the circulation of predominant clade within subtypes.”
But just because this year’s flu vaccine was unexploded doesn’t mean it’s not worth taking.In a typical year, the flu vaccine idea To prevent millions of influenza cases, tens of thousands of hospitalizations, and at least thousands of deaths, despite the fact that only about half of all Americans are vaccinated.There is also a next-generation influenza vaccine close to development, May allow for a better match to circulating stocks.And there is still the appeal of universal or longer lasting flu vaccines Appetizing Within the scope of grasp.
The last two winters also remind us that the flu season is bad. It doesn’t have to be inevitableEven if there is no very effective vaccine.