HealthDay News — Booster doses seem effective for the SARS-CoV-2 omicron variant, according to research published in the January 21 early-release issue of the US Centers for Disease Control and Prevention Morbidity and Mortality Weekly Report.

Amelia G. Johnson, Dr PH, from the CDC COVID-19 Emergency Response Team, and colleagues estimated incidence rate ratios (IRRs) among unvaccinated and fully vaccinated adults by receipt of booster dose during the pre-delta (April to May 2021), delta emergence (June 2021), delta predominance (July to November 2021), and omicron emergence (December 2021) periods. The researchers found that for unvaccinated vs fully vaccinated persons, the average weekly, age-standardized case IRRs decreased from 13.9 pre-delta to 8.7 as delta emerged and to 5.1 during delta predominance. Case IRRs decreased to 4.9 and 2.8 for fully vaccinated persons with booster doses and those without booster doses, respectively, during omicron emergence relative to October to November 2021.

Mark G. Thompson, Ph.D., from the CDC COVID-19 Response Team, and colleagues analyzed 222,772 encounters from 383 emergency departments and urgent care clinics and 87,904 hospitalizations from 259 hospitals among adults aged 18 years and older from August 26, 2021, to January 5, 2022, to examine real-world BNT162b2 vaccine effectiveness (VE). The researchers found that VE against laboratory-confirmed COVID-19-associated emergency department and urgent care encounters was 86, 76, and 94% 14 to 179 days after dose 2, greater than or equal to 180 days after dose 2, and great than or equal to 14 days after dose 3, respectively, during the period of delta predominance. For the same intervals, the corresponding VE estimates were 52, 38, and 82% during omicron variant predominance.

“All adults who have received mRNA vaccines during their primary COVID-19 vaccination series should receive a third dose when eligible, and eligible persons should stay up to date with COVID-19 vaccinations,” Thompson and colleagues write.

Several authors from the Thompson study disclosed financial ties to the pharmaceutical industry.

Full Text – Johnson

Full Text – Thompson