Covid19 vaccine efficacy dropped as Delta variant arose : CDC
The effectiveness of coronavirus vaccines in frontline workers fell to 66 per cent after the Delta variant emerged compared to 91 per cent before it became dominant, according to a report from the US Centers for Disease Control and Prevention.
The CDC, however, warned that the findings of the study should be interpreted with caution as vaccine effectiveness might wane over time and the estimates of efficacy were approximate, according to a Bloomberg report.
“Although these interim findings suggest a moderate reduction in the effectiveness of Covid-19 vaccines in preventing infection, the sustained two-thirds reduction in infection risk underscores the continued importance and benefits of Covid-19 vaccination,” researchers wrote in the agency’s Morbidity and Mortality Weekly Report, according to Bloomberg.
The findings match the earlier claims made by Israel and UK that vaccines lose some potency over time, especially after the more virulent Delta variant emerged.
This and other results will be under examination next week as CDC advisers will weigh the Biden administration's decision to administer booster doses to people who have been fully vaccinated.