Prognosis

Vaccine Efficacy Diminished as Delta Arose, CDC Report Shows

CDC advisers to consider data on boosters next week in meeting
Researchers urge taking care with interpretation of results

WATCH: Goldman is requiring employees to don masks and prove they’ve been vaccinated to enter the U.S. workplaces. Meanwhile, a report from the UCDC shows that the effectiveness of the vaccines among front-line workers declined after the delta variant became dominant. Kara Wetzel reports.(Source: Bloomberg)

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By John Tozzi

August 24, 2021 at 5:01 PM UTC

Updated on

August 24, 2021 at 8:14 PM UTC

This article is for subscribers only.

The effectiveness of Covid-19 vaccines among front-line workers declined to 66% after the delta variant became dominant, compared with 91% before it arose, according to a report from the U.S. Centers for Disease Control and Prevention.

The vaccines are still protective, the CDC said, and the finding must be interpreted with caution, as vaccine effectiveness might wane over time and the estimates of efficacy were imprecise.