What you should know
- Changes in human behavior around masking and other COVID protocols, plus the rapid rate at which the highly contagious delta variant spread this summer may have had more to do with decreased vaccine efficacy than immune decline according to a New York State Department of Health study released Monday.
- The pre-printed, non-peer-reviewed study finds that the three federally licensed vaccines for emergency use continue to show great effectiveness against reinfection and even greater success in preventing severe cases.
- As part of the study, the researchers screened nearly nine million adult New Yorkers for possible changes in vaccine effectiveness by age, product, and months of vaccination.
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NEW YORK – Changes in human behavior around masking and other COVID protocols, plus the rapid rate at which the highly contagious delta variant spread this summer may have had more to do with declining vaccine efficacy than with immunological decline, according to a New York State Department of Health study published Monday.
The pre-printed, non-peer-reviewed study finds that the three federally licensed vaccines for emergency use continue to show high effectiveness against reinfection and even greater success in preventing severe cases, with modest reductions to recipients from Pfizer and Moderna. age 65 and older, which supports specific booster dose recommendations, the department found.
In what Dr. Howard Zucker, outgoing commissioner of the New York State Department of Health (or DOH), calls the largest study in the US by vaccine type and time of vaccination performed To date, researchers have screened nearly nine million adult New Yorkers for possible changes in vaccine effectiveness by age, product, and months of vaccination.
They looked at people vaccinated between January and April 2021 and examined their levels of newly diagnosed infections and hospitalizations from May to August 2021, compared to people who never received a single dose of any of the three vaccines.
Among the main findings are:
- Decreases in vaccine effectiveness against laboratory-confirmed COVID infections were greatest for Pfizer-BioNTech recipients (-24.6% for those ages 18 to 49, -19.1% for those ages 50 to 64 years and -14.1% for those over 65) compared to Moderna (-18% decrease in vaccine effectiveness for 18-49, -11.6% for 50-64 and -9.0%) and Johnson & Johnson (-19.2% for 18-49, -10.8% for 50-64 and -10.9% for 65+);
- Those declines occurred simultaneously in age groups, vaccine type, and during the weeks in which the prevalence of the delta strain in New York and the country grew most rapidly. Pfizer recipients saw the largest declines for all three types of vaccines during that period;
- Once the delta exceeded 85% prevalence among all New York COVID strains, those variations leveled off. More recently vaccinated people were found to have higher levels of protection in some groups, while modest and continued declines were seen for the older population, suggesting that a particular variant and less intense personal prevention behavior contributed greatly. to decreased effectiveness.
- The effectiveness of the vaccine against hospitalization for adults aged 18 to 64 years remained at 86% at all ages over time; Among those 65 and older, effectiveness decreased from May to August for recipients of Pfizer (95% to 89.2%) and Moderna (97.2% to 94.1%). J&J recipients saw lower effectiveness overall, with a range of 85.5% -82.8% with no difference related to the time period studied.
“This latest study by our renowned scientists here at DOH is the largest to examine in depth changes in vaccine effectiveness over time broken down by the three types of COVID-19 vaccines currently licensed for use. use in the United States, “Zucker, lead author of the study, said in a statement announcing its launch.
“It clearly demonstrates what we’ve been saying all along: getting a COVID-19 vaccine is still the best way out of this pandemic and the best way for New Yorkers to prevent serious illness and hospitalizations,” he added.
The study’s lead author, Dr. Eli Rosenberg, from the Department of Health, said research supports the need for booster doses of the vaccine among older people in particular. He noted that while there was evidence of an early decline in the effectiveness of the reinfection vaccine in younger people, that leveled off once delta established dominance.
“Taken together, this suggests that ongoing declining protection may be less of a concern for adults under 65,” Rosenberg said.
Currently, Pfizer is the only manufacturer whose vaccine booster is approved by the federal government for emergency use in the United States.
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