Protection by Vaccines and Previous Infection Against the Omicron Variant of Severe Acute Respiratory Syndrome Coronavirus 2
2022
Abstract
BACKGROUND: The Omicron variant of SARS-CoV-2 evades immunity conferred by vaccines and previous infections. METHODS: We used a Cox proportional hazards model and a logistic regression on individual-level population-wide data from the Czech Republic to estimate risks of infection and hospitalization, including severe states.
RESULTS: A recent ( 6 months after a previous infection. The OR for Omicron relative to Delta was 0.36 (CI: 0.34-0.38) for hospitalization, 0.24 (CI: 0.22-0.26) for oxygen, and 0.24 (CI: 0.21-0.28) for ICU admission.
DISCUSSION: Recent vaccination still brings substantial protection against severe outcome for Omicron.