COVID-19 vaccines and booster shots had a high efficacy against severe outcomes during the Omicron wave, reported a large real-world study from the US Centers for Disease Control and Prevention (CDC).

The study assessed data from over 300,000 visits to emergency departments, urgent care clinics, and hospitalizations in 10 states between August 26, 2021 and January 5, 2022. During the period when the Delta variant dominated, efficacy of vaccines against COVID-related hospitalization was 90% between 14 and 179 days following the second dose of a vaccine. It declined to 81% more than 180 days after the second jab, and increased to 94%, 14 days or more following the third dose.

After the Omicron variant became dominant, vaccine efficacy against hospitalization between 14 and 179 days after second dose was 81%, declined to 57% more than 180 days after dose two, and rose to 90%, 14 or more days after the third jab.

Another paper from the agency, based on data obtained from 25 state and local jurisdictions in the United States, noted that vaccine efficacy against infection dropped from 93% prior to Delta to close to 80% when Delta became dominant; however, protection against death was stable at 94%... (NDTV – AFP, January 22, 2022)