The flu causes millions of infections and hundreds of thousands of deaths every yearas documented in a study from “The Lancet” which generates natural immunity in survivors. This immunity, together with that induced by vaccination, forms a complex history of pre-existing immunity in the human population, different for each individual.
The role of Pre-existing immunity is crucial in determining the strength and extent of future protection against vaccines; however, the direction and magnitude of this impact remain unclear. By looking at the cumulative immune history of each individual, some researchers say it could be a “original antigenic sin“, suggesting that the virus that causes the first influenza infection may establish a dominant memory in the human immune system, hijacking the immune response and potentially hijacking protection against infections caused by other influenza viruses, as described by a article collected in the database Dialnet.
On the other hand, others consider it an antigenic antiquity or antigenic fingerprintwhich provides cross-protection when a new strain appears. The complex history of infection and vaccination within the human population has posed extreme difficulties in exploring the impact of pre-existing immunity. Therefore, animal models have gained popularity as an alternative approach to study this phenomenon.
Now comes a new study funded by the United States National Institutes of Health (NIH) and carried out by researchers from University of Georgia (UGA) who discovered that natural immunity against infections of flu above has a significant impact on the performance of future influenza virus vaccines. The work was published in “Vaccine”.
Background
This may mean that if you’re one of the lucky ones (1 in 5 Americans) who get the flu each year, according to the NIH, your illness may have an unexpected positive effect. This could help you fight future versions of the virusdocuments the work.
“In general, pre-existing immunity that develops during natural infection helps strengthen immune responses,” he said in a statement. Ye Shencorresponding author of the study and professor at the UGA School of Public Health.
And he insisted: “Prior to this study, we did not completely understand how pre-existing immunity due to natural infection with different strains of the influenza virus modifies the immune responses caused by the infection.” vaccine. Now we have a better understanding of how pre-existing immunity to influenza influences immune responses to different types of vaccines.
Flu vaccines aim to track the evolution of a virus. Each season of the disease, it targets certain strains of the virus. So when scientists develop the flu vaccine, they must make educated guesses about which strains are most likely to be circulating in advance. Even though a lot of research goes into development, it will never be 100% accurate. THE ability of the influenza virus to constantly evolve and the development of new, more virulent strains is why it is difficult to combat.
The doubts of the population
“Some years we haven’t had very good vaccine protection because of this disparity. People are starting to wonder if the vaccine really protects them from the flu. because of that. However, with this study, we see benefits to having pre-existing immunity, and that is good to know,” the researcher confirmed.
Researchers tested vaccines made with different strains of flu and found that when animals were infected with one of those strains, they had an increased immune response when they received the vaccine targeting that same strain. But overall immunity also improved significantly when animals received a vaccine targeting a different strain of fluafter being infected with the corresponding strain. Because the body protected itself against one strain with its natural immune response and the vaccine caused broader immune responses against a spectrum of strains, the body was better protected.
Natural immunity
Animals that were not initially infected with the virus but received the vaccine were more likely to need a booster dose because they lacked natural immunity. This research is part of a larger study seven-year NIH-funded project that aims to create universal infection-fighting vaccines for vulnerable populations.
“Our future studies will explore more clinically relevant outcomes, including real infections in humans. It may not be enough to simply increase antibodies. Is this enough to protect you from mutations in different flu strains? This is where the heterogeneity At the individual level, this becomes important, which remains an ongoing area of research in this area,” he noted.
