Despite 100% of blood donors having vaccine-induced antibodies, infection-acquired seroprevalence continued to rise by the end of October 2022, to 67.3%, up from 63.2% at the end of September.
According to Canadian Blood Services, the infection-acquired antibody rate increased moderately from 65.4% in the last week of September to 66.3% by mid-October, consistent with the continued circulation of Omicron subvariants. Seroprevalence due to infection surpassed 80% among young donors (17-24 years of age) and 70% among the most materially deprived.
CITF-funded researchers at Héma-Québec, led by Drs. Marc Germain and Dr. Renée Bazin, published a preprint, not yet peer reviewed, reporting on the characteristics of the plasma donors whose samples are used to study COVID-19 immunity in Quebec.
Héma-Québec estimates that 62% of Quebecers who donated plasma had acquired antibodies following an infection with Omicron by the end of August 2022.
Consistent with the continued prevalence of the Omicron variants (predominantly BA.4, BA.5 and BA.5 subvariants), infection-acquired seropositivity continues to increase among blood donors, up to 65.41% by the end of September, from 60% in the last week of August. These data come from Canadian Blood Services.
A report published in the Annals of the New York Academy of Sciences, prepared with the participation of the CITF-funded Serotracker team, presents the outcomes of the April 2022 Keystone symposium on the successes and challenges of the COVID-19 pandemic. Rahul Arora (University of Calgary) participated as a representative of the CITF-funded SeroTracker initiative.
A systematic review carried out by the CITF-funded SeroTracker team, released in preprint, and not yet peer reviewed, reported that third-party or independent evaluations from manufacturers found that the manufacturers appear to overstate the sensitivity and specificity of their serological assays targeting SARS-CoV-2.
In a study published in the International Journal of Epidemiology, the CITF-funded SeroTracker team, including Dr. Rahul Arora (University of Calgary), contributed to showing that only 70% of individuals invited to participate in seroprevalence studies actually enrolled.
In a systemic review published in BMJ Global Health, Dr. Rahul Arora (University of Calgary) and the CITF-funded SeroTracker team estimates that seroprevalence in Africa (due to infection or vaccination) was 65.1% in July-September 2021.
In a letter published in the New England Journal of Medicine, the CITF-funded Ab-C Study led by Dr. Prabhat Jha, from the University of Toronto, quantified SARS-CoV-2 incidence during the Omicron (BA.1/1.1) wave among Canadian adult members of the Angus Reid Forum.