Association of SARS-CoV-2 infection with interdonation interval: A matched cohort study of plasma donors in Québec, Canada

Blood services witnessed significant declines of donor returns during the COVID-19 pandemic. Should another public health crisis occur, this experience may provide important insights for the development of strategies to maximize donor return. Here, we explored how contracting a SARS-CoV-2 infection impacted interdonation interval.

This was a retrospective cohort study of plasma donors who were not SARS-CoV-2-vaccinated at the time of inclusion. The study took place in Québec, Canada. Donors were included if they had donated plasma twice: once between March 1 2020 and 30 June 2020 and once more within the next 24 months. Donors with ('infected') and without ('non-infected') a self-reported SARS-CoV-2 infection were matched 1:1 based on sex, age and number of previous donations. Cox proportional hazard ratios (HRs) and 95% confidence intervals (CIs) were reported.

The matched cohorts each comprised 108 donors, including 50.0% of female donors (mean age ± standard deviation [years]: infected = 40.5 ± 16.2; non-infected = 41.0 ± 16.4). Interdonation interval was significantly longer among infected donors than among non-infected donors, whether it be in the full cohort (HR [95% CI] = 0.566 [0.428-0.749]) or among female donors (HR [95% CI] = 0.429 [0.278-0.660])-but not among male donors (HR [95% CI] = 0.813 [0.527-1.254]).

In this study, a self-reported SARS-CoV-2 infection was associated with a significantly longer interdonation interval.