COVID-19 infection in the Canadian household population.

Background Certain population groups face a disproportionate burden of exposure to COVID-19. This study examined characteristics of Canadians living in private households in fall 2020 and winter 2021 who had been infected with COVID-19. Data and Methods With an online questionnaire and an at-home finger-prick blood test, the Canadian COVID-19 Antibody and Health Survey was designed to estimate the seroprevalence of COVID-19 infection among people in private households in Canada. Data were collected from respondents aged 1 or older in the 10 provinces and the three territorial capitals, from November 2020 to April 2021. Descriptive statistics and logistic regression were used to identify characteristics that were associated with being seropositive for a past COVID-19 infection. Gender differences in observed associations were examined. Results After covariate adjustment, younger age and visible minority status were associated with an increased likelihood of being seropositive for a past COVID-19 infection. For males, having a visible minority status, having less education and living in a multi-unit dwelling increased the likelihood of being seropositive. Females were more likely to have been seropositive if they worked in health care in direct contact with others. Interpretation As Canada navigates the fifth and possibly a sixth wave of the pandemic, understanding who was more likely to be infected in earlier waves can help ongoing public health efforts to stop the transmission of COVID-19.