Decline in protection against SARS-CoV-2 Omicron in prior infected and fully vaccinated

In a recent study posted to the medRxiv* preprint server, researchers investigated the distribution of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Delta and Omicron variants among coronavirus disease 2019 (COVID-19) positive individuals who were either naive, fully vaccinated, or had a previous infection to further investigate possible escape from vaccine- or infection-induced immunity by Omicron compared to Delta.