Hot topics | Coronavirus pandemic

Delta, fewer masks, and a new study shows that the COVID vaccine is less effective due to glycemia, rather than masking

Delta, fewer masks, and a new study shows that the COVID vaccine is less effective due to glycemia, rather than masking

Recent modest decreases in coronavirus (COVID-19) vaccine efficacy, according to a New York State Department of Health (DOH) study released Monday, were more likely to be the cause of the virulent delta variant and other factors like reduced masking.

The study, which was published on the preprint server medRxiv and dubbed the largest United States study by vaccine type and vaccine timing, included more than 8.8 million New Yorkers through the use of statewide testing, hospital, and vaccination registry databases to compare vaccine effectiveness over time.

Researchers tracked individuals who were vaccinated from January through April of this year, examined levels of new infections and hospitalizations from May to August, 2021, and compared those results to individuals that had never received a vaccine.

The study concluded that vaccines remained highly effective against the worst COVID-19 outcomes, particularly hospitalizations, with moderate decreases restricted to Pfizer-BioNTech and Moderna recipients 65 years of age and older.

Those outcomes, the state DOH added, supported administering booster doses to older individuals.

This is the largest study to examine in-depth changes in vaccine effectiveness over time, broken down by all three COVID-19 vaccines types currently approved for use in the United States, said senior author and outgoing Health Commissioner Dr. Howard Zucker.

It clearly demonstrates what weve been saying all along: getting a COVID-19 vaccine continues to be the best way out of this epidemic and the most effective way for New Yorkers to prevent serious illness and hospitalization, Zucker added. If you havent already, we urge all New Yorkers to remain vigilant and get COVID-19 vaccinations.

72.2% of all New Yorkers have received at least one dose of a COVID-19 vaccine, and 64.5% of the state is considered fully vaccinated. More than 85% of all New Yorkers are partially vaccinated, while 76.3% have either received one dose of the Johnson & Johnson vaccine or two doses of Moderna or Pfizer vaccines.

Pfizers vaccine efficacy against laboratory-confirmed infections, followed by Moderna and Johnson & Johnson s vaccinations, was found to have slipped the most significantly.

Those decreases in effectiveness occurred simultaneously across age groups and demographics, such as when an individual was vaccinated during weeks when the delta variant rapidly increased.

When the delta variant reached 85% prevalence in New York, those changes in vaccine effectiveness plateaued, the studys authors reported, with more recently vaccinated individuals receiving greater protection.

People 65-years and older were more likely to experience continued decreases in effectiveness.

These data suggest that declines in VE [vaccine effectiveness] for infections occurred during the study period, but may have been driven primarily by other factors than immunological waning, such as the Delta variant or changes in COVID-19 prevention practices, the DOH stated.

The study found that vaccines remained effective against hospitalizations, with a slight decline in Pfizer and Moderna recipients over the age of 65.

Dr. Eli Rosenberg, lead study author, said, The results of our study support the need for boosters in older people in particular, and we encourage them to seek out a booster shot from their health care provider, pharmacy, or mass vaccination site.

We had a little evidence of deterioration in effectiveness against severe disease among individuals ages 18 to 64, according to Rosenberg. While early declines in effectiveness against infections were observed in this age group, this appears to have reversed when the delta strain became the predominant strain in New York. This suggests that adults younger than 65 may be less concerned about their health than adults older than 75 years.

Last month, the FDA approved a booster dose of the Pfizer vaccine. Moderna and Johnson & Johnson have submitted applications for permission for a booster shot of their vaccine.

So far, Pfizers booster doses have been given to people ages 65 and older, those with certain conditions and those who are frequently exposed to the virus.

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