Vaccine Effectiveness in New York Dropped as Delta Variant Surged During Summer, Study Shows

People wait to attend the Broadway musical "Hamilton" after showing their vaccination cards at the Richard Rodgers Theatre in New York on Sept. 14, 2021. TIMOTHY A. CLARY/AFP via Getty Images

The effectiveness of the three COVID-19 vaccines dropped significantly over the course of 10 weeks this summer when the Delta variant exploded to become the dominant strain of the CCP virus, according to a preprint study (pdf).

Scientists from the New York State Department of Health and the University at Albany School of Public Health studied the vaccination, testing, and hospitalization records of more than 8.8 million New Yorkers for the period between May 1 and July 10 this summer.