Influenza germinates at the wrong time – Picture of the Day – Kommersant

The usual time for influenza vaccination is September-October, which is what most doctors recommend. Recently, however, disputes have escalated among scientists when it is most effective to vaccinate: someone leans towards November, while someone generally advises to be vaccinated twice a year. The flu epidemic is likely to return this year. During the two years of the pandemic, the number of children who have not yet been exposed to this virus has increased dramatically.

Most doctors recommend getting a flu shot in the fall. The American Centers for Disease Control and Prevention (CDC) has been advising for about 60 years to get vaccinated no earlier than September and, if possible, no later than the end of October. Recently, however, disputes have escalated among specialists about when exactly it is worth vaccinating against influenza, as well as how many doses of the drug should be administered, and not everyone agrees with generally accepted recommendations.

This is due to the fact that immunity after flu shots decreases quite quickly and at the same time the flu outbreak sometimes turns out to be late and occurs at the end of winter.

According to research, published in 2020 by the Kaiser Permanente Vaccine Research Center and the Harvard School of Public Health, every 28 days after vaccination, immunity against influenza decreases by about 18%. In a different researchconducted by the CDC, we are talking about a decrease in immunity by 8-9% per month, and in people aged – by 10-11% per month.

“You have about four months of pretty good protection,” said University of Michigan School of Public Health epidemiology professor Emily Martin.

According to many experts, it is impossible to give exact recommendations for the timing of the flu shot, since its outbreaks occur at different times in different years and in different places. “I don’t think it’s a good idea to start (getting flu shots.— “b”) now,- declared in early September, Florian Krammer, influenza expert at the Icahn School of Medicine at New York’s Mount Sinai Hospital.

He said that he gets vaccinated in November: in this case, the immune response is formed by January-February, when the flu epidemic usually begins, and remains quite high later. According to Mr. Krammer, about three-quarters of all influenza epidemics between 1982 and 2020 did not peak until January.

Many experts say that they themselves will choose the time of vaccination depending on when an outbreak may begin, and recommend that other people do the same. “I will monitor activity (morbidity) very carefully— “b”) in the community. If it starts to grow, I will do it immediately. Otherwise, I’m looking at the end of October – the beginning of November, ”says Michael Osterholm, head of the Center for Research and Policy on Infectious Diseases at the University of Minnesota.

It is precisely the fact that influenza epidemics occur at different times each year that makes it difficult to attempt to bring vaccination closer to the start of the epidemic.

“Trying to predict flu seasons is in many cases much more difficult than forecasting in the stock market,” says Mr. Osterholm.

The COVID-19 pandemic further complicated such forecasts. In the winter of 2020-2021, there was no influenza epidemic, and last winter it was unusually long, but much weaker than before. According to experts, this year the influenza epidemic is likely to return. Moreover, during the two years of the pandemic, the number of children who have never encountered this virus has increased.

Experts believe that the recommendation to vaccinate in September-October is due, among other things, to the fact that it is easier for healthcare institutions to carry out a vaccination campaign in a limited time frame, rather than stretch it out for a longer time. This year, the CDC is also advising people to get their flu and COVID-19 shots at the same time.

According to Noel Brewer, a professor at the University of North Carolina at Chapel Hill, this is the right decision. If people have to keep track of when they need a revaccination, they are more likely to miss them and forget about the vaccine.

In fact, spreading the influenza vaccination campaign over several months will help to reduce the number of vaccinated, although it may make the vaccine more effective for individuals.

“People are busy and health systems want to make sure most of them are protected before the season starts,” said Ali Ellebedi, an epidemiologist at Washington University in St. Louis. In his opinion, by postponing vaccination until November, a person risks catching the flu if the incidence starts to rise earlier, or simply forgets to get vaccinated in the end.

“This is a compromise between starting too early and weakening the action (vaccinations.— “b”) and missed vaccination opportunities. If you try to optimize the timing, you lose people who are not vaccinated at all in this case. Trying to balance that is tricky because you don’t know when flu season will start in that particular year,” said Ed Belonja, head of the Mashfield Clinical Research Institute’s Center for Clinical Epidemiology and Population Health. In his opinion, this is a choice between collective and personal immunity.

Some experts are inclined to the option of two vaccinations per season. American physician and professor emeritus of virology at the Wistar Institute (Pennsylvania) Stanley Plotkin – he advised many vaccine manufacturers and was one of the creators of the rubella vaccine – said that he gets the flu shot twice: in October and January. However, he notes that this is not a recommendation for everyone, but his personal decision.

There is still little research on the effectiveness of two flu shots a year.

University of Hong Kong epidemiologist Ben Cowling studied the effect of two vaccinations on Hong Kong residents, who often face two influenza waves a year. He concluded that a second shot boosts the immune response, so “there’s nothing wrong with getting vaccinated twice a year,” other than financial and logistical costs. However research in the United States, where the epidemic occurs once a year, show rather no additional benefits from two vaccinations in a year with a small gap between them.

Yana Rozhdestvenskaya