mRNA vaccine efficacy dropped 'significantly' among nursing home residents: CDC
A new CDC analysis found that Pfizer and Moderna vaccine efficacy dropped "significantly" among nursing home residents from March to July, as the delta variant became the predominant strain in the United States.
![PHOTO: A syringe is filled with a dose of the Pfizer Covid-19 vaccine at a mobile vaccination clinic during a back to school event at the Weingart East Los Angeles YMCA in Los Angeles, Aug. 7, 2021.](https://s.abcnews.com/images/International/vaccine-california-gty-jt-210817_1629229868768_hpEmbed_3x2_992.jpg)
Researchers analyzed weekly reports from thousands of nursing home facilities in the U.S. and found that mRNA vaccines were roughly 75% effective against preventing any infection in late winter/early spring of 2021, early in the mass vaccination rollout and prior to the emergence of the delta variant. By summer of this year, effectiveness against any infection had dropped to 53%.
Crucially, this doesn't mean vaccines aren't working for nursing home residents, but the significant drop in effectiveness from March to July may support the use of booster doses for them, according to the CDC report.
A second analysis found that the mRNA vaccines are holding up well against hospitalizations for COVID-19. The research, which was conducted across 21 U.S. hospitals, found that the Pfizer and Moderna vaccines remained between 84% and 86% effective against potential hospitalizations from March to July of this year. A third analysis, conducted in New York State, found that all three authorized vaccines remained more than 90% effective at preventing hospitalization from early May to late June.
-ABC News' Sony Salzman, Eric Strauss