Contracting COVID-19 “appears” to protect more against reinfections than receiving two doses of vaccine, indicates the National Institute of Public Health of Quebec (INSPQ) in a notice published recently. What’s more, two doses and one infection confer the best possible immunity, according to what science can say so far.
A “systematic review of studies” comparing the protection conferred by infection with that resulting from vaccination “appears” to indicate that contracting COVID-19 is more effective than two doses of “different vaccines” in preventing serious reinfection. However, this analysis was carried out before the arrival of Omicron.
The “highest” antibody levels were found in previously infected people who then received two doses of vaccine, the Quebec Immunization Committee (CIQ) reported on January 28.
The immunity acquired both by vaccines and by infection with Omicron is effective “against all the variants known to date”, we continue.
“It is unknown whether a third dose of vaccine given to an individual who has had the infection before and is vaccinated with two doses will further increase the immune response,” the CIQ also notes.
The expert committee stresses that it is still too early to establish the degree of protection offered by an infection with Omicron alone.
As for the natural infection, it produces antibodies that persist in recovered people “up to 12 months” after the disease was contracted.
The INSPQ does not recommend obtaining a third dose if one has already reached the immunity ceiling acquired with two doses and an infection. “Waiting for new vaccines that offer a wider range of protection would be the best option in this case. »
Pfizer said it could have 100 million doses of a variant-matched vaccine as early as March.
Moderna wins over Pfizer
In addition, the Moderna vaccine is more effective than its competitor from Pfizer in preventing hospitalizations, according to a peer-reviewed study published in the Journal of the American Medical Association.
The proportion of infections and hospitalizations is lower in the individual with two doses of Moderna, attest the researchers. However, the protection against death is very similar for the two vaccines.
At a two-dose regimen, Moderna still outweighs disease symptoms, according to a different study published in December in the New England Journal of Medicine.
This efficiency is 96.3% for Moderna, against 88.8% for Pfizer.
These studies were all performed when the Delta variant was dominant. There is currently no evidence to establish which of the two vaccines is more effective against Omicron.
This text is taken from our newsletter “Coronavirus mail” of February 1, 2022. To subscribe, click here.