Why are some people resistant to the Covid-19 virus?
Are there people who have no chance of contracting Covid-19? Apparently yes. Or at least this is what was discovered by an international study carried out, for the Italian part, by a team of researchers from the Roman University of Tor Vergata., the "observation of people who, despite direct and extremely close contacts with positive subjects, were not infected, almost as if they could count on a barrier, invisible but very effective and resistant, able to protect them." They are people who certainly were exposed, therefore in contact, with those who had the disease in progress, but despite this they are negative to any type of test, both molecular and serological, as well as corresponding to a whole series of criteria that serve to clearly identify this We are collecting subjects with these characteristics from around the world to genetically analyze them, put together the data and see what they can tell us, "said Giuseppe Novelli, geneticist at the Tor Vergata Polyclinic in Rome and president of the Giovanni Lorenzini Foundation in Milan, group leader of the Italian team of scientists engaged in the study.
The name by which these super lucky ones are identified is resistant, more apt and evocative than ever, which recalls both physical resistance to the virus and psychological resistance to the pandemic.
What would make you insensitive to the virus
For science, the existence of people resistant to viruses is nothing new, since these are events that almost always arise, but in this case the challenge was to identify the causes of this phenomenon.
What makes some people actually immune to Sars-Cov2 infection would be above all specific genetic conditions, capable of inducing an immune response different from that of the vast majority of the population. This case history is partly reminiscent of that already found with other diseases, such as HIV, where the deletion of the gene, CCR5 delta 32, confers on those who have it a sort of resistance to infection. Despite the numerous studies carried out over the years, even in that case the protection mechanisms are still not completely clear. As well as those relating to immunity from Covid-19.
a Canadian study conducted on over 220 thousand people, and which appeared a few months ago in the Annals of Internal Medicine, has also shown this to affect the contagion and the disease ", explains the" infectious disease specialist Roberto Cauda, professor of infectious diseases at the Catholic University and director of the " Infectious Diseases Operating Unit of the Agostino Gemelli Irccs Polyclinic in Rome According to that research, blood group 0 would have a 12% less chance of contracting the virus, a percentage that improves, rising up to 21%, in the case of Rh negative. People with group A and AB blood, on the other hand, seem to be more susceptible to the Covid-19 virus.
of people because that is where the genetic differences reside ", said prof. Giuseppe Novelli.
The first step taken by the experts was to focus on those who contracted the disease in a serious way. "First we studied the serious cases, that is the most interesting from a scientific point of view because genetics focuses on the extremes to find the differences, ”says Prof. Novelli.
The role of interferon
From the observations it emerged that the likelihood of becoming infected or not would also be determined by the "interferon. As specified in detail by the Tor Vergata research report, published in the prestigious journal Science," Individuals who lack specific IFN (interferons) may be more susceptible to infectious diseases ".
At the end of the detailed observation, it was found that 10-12% of seriously ill Covid-19 sufferers reported genetic differences in the production of interferon, the number one defense molecule the body produces when it becomes infected. thought, in fact, the first line of defense of our organism in the event of a virus attack is not constituted by antibodies, but by the molecules that try to neutralize or block the virus.
Specifically, the research team realized that people who become more seriously ill do not produce interferon. "They lacked the first line of defense called" innate immunity ", and it is very important because if it is defective, it is clear that the virus lives and finds fertile ground."