Infections caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron (B.1.1.529) variant are common among individuals who have recovered from prior infection or have been vaccinated against the coronavirus disease 2019 (COVID-19).
The Omicron has quickly overtaken the SARS-CoV-2 Delta variant as the dominant circulating strain globally. Currently, the original Omicron strain is being replaced by its newer sub-lineages BA.2, BA.3, BA.4, and BA.5. Despite its high infectivity, few studies have documented serial Omicron infectivity.
In a new study published on the medRxiv* preprint server, scientists studied SARS-CoV-2 humoral responses in a healthy young person who was infected by the Omicron BA.1.15 variant ten weeks after receiving a third dose of the BNT162b2 vaccine. This individual was subsequently reinfected with the BA.2 strain thirteen weeks later. The responses of this individual were compared to those of 124 COVID-19 naive vaccine recipients.