Being vaccinated against Covid-19 could also protect against other coronaviruses, including SARS-CoV-1 and the common cold.
- There are three main families of human pathogenic coronaviruses: Sarbecovirus, Embecovirus and Merbecovirus.
- Eventually, researchers could develop effective vaccines for all viruses in the same family of coronaviruses.
Currently, more than 50 million people have received at least one dose of vaccine against Covid-19 in France, including more than 49 million who are fully vaccinated according to the Ministry of Solidarity and Health. These French people are obviously protected from serious forms of SARS-CoV-2 through their injection, but they may also be less likely to be infected with other forms of coronavirus, including SARS-CoV-1 and the common cold. This is suggested by a recent study published in the journal Journal of Clinical Investigation. “Until our study, what was not clear was the possibility, in the event of exposure to a coronavirus, of benefiting from cross-protection against other forms of coronavirusexplains Pablo Penaloza-MacMaster, lead author of the study. We have shown this to be the case.” According to the researchers, previous infections with a coronavirus would also protect against other forms of coronavirus.
SARS-CoV-1 and 2, Mers-CoV, HCoV-OC43: several families of coronaviruses
There are three families of pathogenic coronaviruses for humans. Sarbecovirus first, with SARS-CoV-1 and 2. In 2002, a first SARS-CoV-1 coronavirus emerged in China, responsible for an epidemic of severe acute respiratory syndrome (SARS in French, SARS in English). SARS-CoV-2, better known today, is the virus that causes Covid-19. The Merbecovirus family then with the Mers-CoV, the virus that causes Middle East Respiratory Syndrome, which was first reported in 2012. And the so-called Embecovirus, with HCoV-OC43, a mild virus usually responsible for colds.
Some vaccines protect against other coronaviruses
To reach their conclusions, the researchers analyzed the plasma of humans who had been vaccinated against SARS-CoV-2. According to their conclusions, it protected them both against the virus for which they had been vaccinated, but also against SARS-CoV-1 and HCoV-OC43. Then they worked on mice immunized with a vaccine against SASR-CoV-1. Result: they were also protected – in part – in the event of exposure to SARS-CoV-2. Soon after, other rodents were vaccinated against SARS-CoV-2 and then exposed to the common cold coronavirus (HCoV-OC43). These were then partially protected against the common cold but much less than with the previous experience (SARS-CoV-1 vaccine / SARS-CoV-2 exposure). The reason, scientists say, is that SARS-CoV-1 and SARS-CoV-2 are genetically similar, while the common cold coronavirus is more distant from SARS-CoV-2. The protection is therefore less strong. Finally, the study found that prior infections with coronaviruses could protect against later infections with other coronaviruses.
Towards a vaccine by family of coronavirus?
“As long as the coronavirus is more than 70% linked (genetically to the basic virus for which the vaccine was made), the mice were protected, explains Pablo Penaloza-MacMaster. If they were exposed to a very different family of coronaviruses, the vaccines were less protective.“Scientists do not believe that a universal vaccine against all forms of coronavirus can ever be developed because there are too many differences between the viruses. Nevertheless, a dose for every family could one day exist. “Our study helps us reevaluate the concept of a universal coronavirus vaccine, says Pablo Penaloza-MacMaster. It’s likely there won’t be, but we could end up with a vaccine for each of the main families of coronaviruses, for example a universal Sarbecovirus vaccine for SARS-CoV-1, SARS-CoV-2 and others related to SARS. Others for the universal Embecovirus family for HCoV-OC43 and HKU1 which cause colds.“Vaccines against Covid-19 could therefore still evolve in the coming years.
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