As the vaccination process takes place, a great concern is taking place in communities, especially those in which the speed of the immunization process is less than the capacity of the coronavirus to evolve new antigenic variants over time: how much in How long should vaccines against covid-19 be reevaluated?
People who get vaccines regularly, like the elderly, know that influenza viruses, for example, are skilled dribblers of the human immune system. Their changes are so rapid, that the antibodies produced by our immune system become ineffective in neutralizing them over time. That is why the vaccine against seasonal influenza is repeated every year.
With the day-to-day monitoring of SARS-CoV-2, scientists have already learned that their mutations have produced a number of variants, some of which, like the so-called South African, are already able to partially escape the body’s natural immune response. Vaccine manufacturers are already starting to develop new versions of their immunizer. Will we have to be vaccinated regularly against covid-19?
Studying the gripezinha to understand the covid-19
To assess whether, in the long run, SARS-Cov-2 will demonstrate the same dodging ability as the flu virus, virologists at Charité – Universitätsmedizin Berlin, Germany, compared the genetic evolution of some types of harmless coronaviruses (causing “ common colds ”) with that of influenza viruses.
Attention was directed in a special way to two more well-known coronaviruses (the 229E 4 and the OC43) that have been changing their spike for 40 years, the same as the coronavirus that causes covid-19. According to the first author of the study, Dr. Wendy D. Job, there is a common characteristic among all three types of viruses.
What they have in common is the “repeated replacement of a circulating virus variant with another that has an aptitude advantage”, that is, coronaviruses can also circumvent the immune system.
Results of the comparative study coronavirus vs. flu virus
When comparing the evolution rates of all viruses, the researchers observed that the flu virus accumulated 25 mutations per 10,000 nucleotides (genetic building blocks) per year. In the same period, coronaviruses accumulated about six of these mutations. That is, the rate of change in endemic coronaviruses was four times slower than that of the influenza virus.
Focusing specifically on SARS-Cov-2, it is estimated that it has 10 mutations per 10,000 nucleotides per year, which is a faster rate of evolution than endemic coronaviruses, but lower than that of influenza. But, according to the statement released by the authors, this is due to the high rates of infection observed during the pandemic.
One of the authors, professor dr. Jan Felix Drexler says he hopes “that SARS-CoV-2 will start to change more slowly when infections start to decrease, that is, once a large proportion of the global population develops immunity, either as a result of infection or through vaccination ”.
What is expected is that covid-19 vaccines will be monitored regularly during the pandemic and updated if necessary. “Once the situation stabilizes, vaccines are likely to remain effective for longer,” says Drexler.