Pfizer and Moderna’s COVID-19 vaccines are 100% effective in preventing hospital stays after two doses have been given.
• Read also: LIVE | The latest developments on the coronavirus
This is particularly what emerges from a study carried out by the National Institute of Public Health of Quebec (INSPQ) among nearly 150,000 health workers during winter and spring.
The results show that a single dose of a messenger RNA (mRNA) vaccine reduces the risk of being infected by SRES-CoV-2 by 70.9%, a rate which climbs to 86.9% after the second dose, even though healthcare workers are more exposed than the average person to the virus.
The ability of vaccines to prevent the onset of symptoms is similar, with 73.4% infections without symptoms after one dose and 94.2% after two doses.
However, vaccines have been shown to be particularly effective in preventing hospitalizations, with an effectiveness rate of 97.9% after one dose and 100% after two doses.
During the study, nearly a third of the COVID-19 cases detected (29.2%) in healthcare workers were linked to a variant of concern, mostly the Alpha variant, formerly called the British variant. The data show that the effectiveness of vaccines decreases by about 10% against this variant, which dominated in Quebec this spring.
The study was carried out among 147,535 healthcare workers who had one or more screening tests between January 17 and May 22. They have accumulated 546,046 screening tests that have detected 5,233 cases of COVID-19.
– .
