HealthDay News – Vaccine (VE) effectiveness against infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) fell to 66 percent when the delta variant prevailed, according to a study published in the magazine’s advance copy dated August 24th was published Weekly Report on Morbidity and Mortality of the US Centers for Disease Control and Prevention.
Ashley Fowlkes, Sc.D., of the CDC COVID-19 Response Team, and colleagues updated VE estimates for all COVID-19 vaccines available through August 14, 2021, and examined whether VE increased with time since the completion of the recommended doses differed. Health workers, first responders, and other key and frontline workers at eight U.S. locations across six locations were tested weekly for SARS-CoV-2 infection and if a COVID-19-like illness occurred.
Of 4,217 participants, 83 percent were vaccinated; of these, 65, 33 and 2 percent received the vaccines Pfizer-BioNTech, Moderna and Janssen (Johnson & Johnson). The researchers found that 80 percent of the adjusted VE was against SARS-CoV-2 infection. The VE point estimate was 85 and 73 percent for those participants who had passed <120 and ≥150 days since vaccination was completed; the difference was not statistically significant. The adjusted VE during delta predominance (weeks in which the delta variant accounted for ≥50 percent of the viruses sequenced) was 66 percent compared to 91 percent in the months prior to delta predominance.
“Although these interim results indicate a moderate reduction in the effectiveness of COVID-19 vaccines in preventing infection, the continued two-thirds reduction in the risk of infection underscores the continued importance and benefits of COVID-19 vaccination,” the authors write.
Summary / full text
COVID19 COVID19 Vaccine General Infectious Diseases General Medicine