Infection with the SARS-CoV-2 Omicron variant confers weak, short-term protection against reinfection, compared with the much more robust and durable protection provided by earlier variants, which highlights the need for periodic vaccine updates, a Cornell University Qatar–led study suggests.
The researchers used a test-negative, case-control study design to compare the efficacy of SARS-CoV-2 Omicron infection against reinfection and poor outcomes in Qataris with that offered by infection with previously dominant strains such as Alpha, Beta, and Delta. COVID-positive people were matched with COVID-negative controls in a 1:2 ratio by sex, age-group, nationality, number of underlying medical conditions, vaccine doses received, week of COVID-19 test, testing method, and reason for testing.
The results were published…