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. The analysis found that effectiveness dropped the sharpest for those under the age of 50. The greatest decline in vaccine effectiveness occurred for the Pfizer-BioNTech shot, with a decline of 24.6 percent for people aged 49 and under, 19.1 percent for those 50 to 64 years old, and 14.1 percent for people 65 and over. Effectiveness for the Moderna and Janssen vaccines likewise dropped, although less so than the Pfizer shot. …