Covid: why have some people never been infected with the virus? – Sortiraparis

This is a question that always challenges the scientific community, and that fascinates citizens around the world: what particularities have those who do not have never caught covid-19 ? What weapons do they have to avoid the virus in this way, two years after its appearance, when there are 445 million infections since the beginning of the pandemic in the world?

The hypotheses are numerous, but we cannot, for the moment, be certain. Do these survivors of the coronavirus better respect the barrier gestures than the others, do they have more luck, do they have genetic factors that immunize them against the virus?

In France, it is estimated that approximately half of the population never caught the virus. The exact figure is impossible to know: between the infected but undeclared people, the sick asymptomatic, false negatives, people infected at the very beginning of the pandemic… Many patients have passed under the radar of health authorities.

However, we note that a non-negligible part of the population has, despite everything, never been infected with Covid-19. Various studies offer possible explanations for this.

January 2022, Imperial College London publishes a study in the journal Nature. This research reveals that the antibody provided by contamination with a coronavirus (a family of more or less serious infectious diseases, to which the cold belongs, for example) allow the development of tusks sufficient to prevent Covid-19 infection, even when living with sick people. This phenomenon is called thecross immunity.

” Our study provides the clearest evidence to date that T cells induced by other coronaviruses, such as common cold, play a protective role against SARS-CoV-2 infection “says Ajit Lalvani, co-author of the study.

A second theory often put forward by researchers highlights the role of blood group in immunity to Covid. In fact, people from group O would be more resistant to the virus. On the other hand, they would more easily transmit the disease to others. Some studies on the subject even stipulate that people with blood group O, infected with Covid, have a better chance of avoiding serious forms of the disease and they recover faster.

Covid: people with blood group O better protected against coronavirus, according to a study
Since the start of the pandemic, some studies have estimated that people with blood group O would be better protected from Covid. According to a French researcher, this is indeed true, but the link is not considerable. [Lire la suite]

From the start of the pandemic, many doctors advised taking a cure in vitamin D to escape the virus. A recent Israeli study, conducted by Bar Ilan University and the Galilee Medical Center, highlights the links between infection and vitamin D deficiency.

A genetic mutation could also benefit some individuals in this pandemic. This scenario has already been seen: researchers have discovered that a mutation of the CCR5 gene grants strong immunity against HIV, which cannot enter the body. Scientists are therefore looking for a similar mutation to fight against Covid-19. The ACE2 receptor seems the best candidate in this theory, which is however considered very improbable by Laurent Abel, professor at the Imagine Institute.

For the moment, the scientific community has found no evidence strong enough to give a real explanation. ” Everything is not always explained. We can catch it or not because we are at the moment T more or less in shape with a more or less efficient immune system. If you drink, if you smoke for example, if you are tired… all this can play “Concludes an infectious disease specialist interviewed by France Inter.