The number of Quebecers with anti-COVID-19 antibodies is slowly increasing: Hema-Quebec
MONTREAL – About 15% of adults in Quebec have developed antibodies against the COVID-19 virus since the end of the second wave in the province.
This is what the authors of Héma-Québec’s second seroprevalence study on blood donors say, carried out last March.
The first study, conducted after the first wave in the spring of 2020, showed that just 2.2% of people in the blood donor group had developed antibodies.
The Héma-Québec study reports that people have developed antibodies either after being infected with SARS-CoV-2 or after being vaccinated.
About 10% of the group developed antibodies as a result of infection.
The data also confirmed that the majority of those vaccinated had developed antibodies to the virus.
This second study involved a sample of 7,924 people aged 18 and over who donated blood between January 25 and March 11.
Based on the results, the study estimates the number of people between the ages of 20 and 69 who have developed antibodies to COVID-19 as a result of infection since the start of the pandemic at nearly 600,000.
The authors note that an important finding is that by the end of the second wave, only a small portion of the population was immune. They stress the importance of continuing vaccination efforts across the province.
Analysis of the results shows that seroprevalence, the percentage of individuals with antibodies against an infectious agent, is higher in young people and gradually decreases with age: 19% for 18 to 24 year olds, 16.7% for 25 to 39 year olds. – years, 14.4% for those 40 to 59, 9.8% for those 60 to 69 and 9.5% for those 70 and over.
It is 16.9% for women, against 12.5% for men.
The highest rates were found in the Laval and Montreal regions, at 18.5% and 16.7%.
The study also shows that the rate in Mauricie-Center-du-Québec is 15.8%, higher than the Quebec average. The Chaudière-Appalaches region followed closely behind with 15.6%.
Most of the other regions were below the Quebec average.
A third study will be carried out in the coming months, at the request of the public health authorities, to continue to monitor the evolution of the seroprevalence of COVID-19 in the population.
Héma-Québec studies are carried out in collaboration with the National Institute of Public Health (INSPQ) and in partnership with the Working Group on Immunity to COVID-19 (GTIC).
– This report by La Presse canadienne was first published in French on May 27, 2021.