The good news is scrambling in the fight against the COVID-19 pandemic: after two promising vaccines announced in recent days, a new study suggests that immunity to the coronavirus could last several months.
Posted by American researchers on the pre-publication site bioRxiv, this study indicates that patients who survived SARS-CoV-2 still have, eight months later, enough immune cells to fight the virus again.
“It is indeed good news to know that at least eight months later, there are still antibodies and cellular immunity that seem to protect against the disease,” commented Dr. Caroline Quach-Thanh, from CHU Sainte-Justine.
“We still have to understand what is involved: that we are protected against severe infections, and that we are potentially able to be re-infected very lightly and to re-excrete the virus, but for now it looks good. . “
Scientific evidence to believe in long-term immunity to the coronavirus is slowly accumulating, and this new study supports the same conclusion.
Some are quick to draw a comparison with the SARS pandemic almost 20 years ago, recalling that some survivors still show antibodies 17 years later.
“I am not convinced that the response to SARS-CoV-1 is necessarily superimposable to that of SARS-CoV-2,” said Dr. Quach. It is not a copy and paste. It is not because these are two coronaviruses that we can necessarily say that it is the same, because with other common coronaviruses, we see that people can be re-infected every six months. “
We thus find in the literature a few well-documented cases of patients reinfected with SARS-CoV-2, “but most of these people had next to nothing,” she added.
All of this could bode well for the vaccines that have been in the headlines for ten days.
“It makes us think that vaccines might also be able to have immunity that would be quite durable,” said Dr. Quach. We hope the vaccines (from Pfizer and Moderna) will have immunity longer than six months, that it will last two or three years and more, but only time will tell. “
But even if the news is encouraging, we will have to wait a little longer before considering that the worst of the crisis is over. This virus was unknown to science a year ago, so experts’ knowledge of it cannot be older.
A year later, says Dr. Quach, we have two vaccines that are practically ready to be licensed, unprecedented, but “we are still in the hypotheses and speculation.”
“We must continue to follow the recommendations of physical distancing and wearing of masks until we are able to have a good proportion of the Canadian population vaccinated,” she warned.