A Zurich study shows that infections due to “harmless” coronaviruses can help resist severe forms of the coronavirus responsible for Covid.
SARS-CoV-2, the official name of the Covid-19 virus, is not the only coronavirus in active circulation. Several others, which are sometimes called “human coronaviruses” and which we readily qualify as “harmless” come and go, and we owe them some of the colds that beset us, especially in winter.
They recognize their cousins
A team of researchers from the University of Zurich wanted to know whether the immune responses produced by the human body in contact with these harmless coronaviruses were useful in the fight against infection with the Covid-19 coronavirus. Good news: the answer is yes. Blood samples from 825 donors dating from before the onset of Covid were analyzed for antibodies against coronaviruses. Other samples, from people infected with Covid, were compared to these.
“People infected with SARS-CoV-2 who had high levels of antibodies against harmless coronaviruses were less likely to be hospitalized. A person immune to these coronaviruses is therefore better protected against a serious infection of Covid-19, ”notes the university in its press release.
A good memory
But let’s not rejoice too quickly: having a cold doesn’t have to make us feel invulnerable afterwards. It is said that these people are protected “to some extent”. The researchers also note that the protection conferred by the vaccine is much greater, in particular for chronological reasons.
Whether through infection or a vaccine, the amount of antibody decreases over time. It is then the “memory” of the immune system which can be activated to fight against a new infection, but without neutralizing it. At best, it will reduce its virulence.
The researchers now want to tackle another question, the reverse, which is whether the immunity conferred by vaccines against Covid can also be used to protect us against these other coronaviruses.