Social determinants and factors associated with use of SARS-CoV-2 self-tests during the first months of self-test availability: findings from a population-based cohort study in France

Background. Self-tests for SARS-CoV-2 became quickly available after the onset of the epidemic. They were especially recommended for high-risk and hard-to-reach populations. This study examines whether self-tests successfully reached these groups during first months of availability in France. Methods. The EpiCov study is a national, population-based cohort study conducted in France during the Covid-19 pandemic. Primary outcome variable was use of self-test at last SARS-CoV-2 test, among those who reported testing at least once between May and July 2021. Univariate and multivariable binomial weighted logistic regressions were conducted, stratified by age group (16–24, 25–59, 60+ years), to identify social determinants (according to the PROGRESS+ framework) and factors associated with use of self-tests. Results. Overall, 11% of the population who tested for SARS-CoV-2 between May and July 2021 reported using a self-test as last test. Use of self-tests was highest among 16–24 year-olds, individuals with higher education, lowest population density areas, and individuals with high overall frequency of testing. Use was lowest among 60+ year-olds, unemployed and retired people, and first-generation immigrants. When stratifying by age, demographic factors were highly predictive of use of self-tests among 25–59 year-olds, but not among younger and older age groups. 16–24 year-olds with high perceived Covid-19 risk vs low perceived risk were more likely to use self-tests (aOR 1.99 [95%CI 1.10-3.59]). Among 25–59 year-olds, in-person workers were more likely to use self-tests than remote workers (aOR 1.90 [1.20-3.02]). Among 60+ year-olds, employed individuals were more likely to use self-tests than retired individuals (aOR 3.77 [2.19-6.51]). Conclusions. Use of self-tests during first months of availability in France represents 11% of total tests. With higher utilization in lowest population density areas and among young adults, convenience appears to be a primary driver of use of self-tests. Additional drivers include perceived risk among younger individuals, and exposure at work for those ≥25 years. Inequities in use were observed, with lower use among people with low education, older age, and immigrants.