Characteristics of Quebec plasma donors used to study COVID-19 immunity

CITF-funded researchers at Héma-Québec, led by Drs. Marc Germain and Renée Bazin, published a paper in BMJ Open reporting on the characteristics of the plasma donors whose samples are used to study COVID-19 immunity in Quebec. More than 86,000 plasma samples have been collected from more than 15,500 individual donors in its COVID-19-focused PlasCOV biobank. The samples are representative of the general population, ranging in age from 18 to 84, with nearly a 50/50 split between males and females.

Key messages:

• Nearly two thirds (65.6%) of donors made at least two donations, thereby allowing for longitudinal analyses. Many donors provided samples pre- and post-vaccination (3061 [19.7%]), while a small group provided samples pre- and post-infection (131 [0.8%]). A forthcoming seroprevalence study is underway to compare anti-N responses pre- and post-infection in order to estimate the incidence of recent infections in the context of the Omicron wave.
• Serosurveys conducted using biobank samples show that the anti-N antibody response wanes rapidly. Up to one third of previously infected donors no longer had anti-N antibodies after six and a half months.

Researchers highlighted the importance of the longitudinal nature of the biobank, which provides better insights into SARS-CoV-2 immune responses to inform public health officials, especially those in Québec. The cohort is still ongoing, with blood donations being collected up until March 31, 2023.

The PlasCoV biobank, funded by the CITF, was established in April 2021 by researchers at Héma-Québec to better understand infection-acquired and vaccine-induced immunity to SARS-CoV-2. Ten blood centers are designated to collect biobank-dedicated samples and the donor cohort is representative of generally healthy adults living in urban and suburban areas throughout Québec.