A federal report released Tuesday estimated that vaccinations between January and May of this year led to a reduction of 265,000 COVID-19 infections, 107,000 hospitalizations, and 39,000 deaths among Medicare beneficiaries.

During the first nine months of the pandemic, nearly 80% of deaths were among people 65 and older who were eligible for Medicare, said the report, which was produced by the Department of Health and Human Services’ Office of the Assistant Secretary for Planning and Evaluation.

The report was based on county-level data on vaccination rates and claims data for Medicare fee-for-service plan recipients. Researchers extrapolated results to those with Medicare Advantage plans, who tend to be older, sicker, and poorer than those in traditional Medicare. Data used in the analysis predate the dominance of the more infectious delta variant and evidence that older and immunocompromised people who were vaccinated early this year may now be more vulnerable to breakthrough infections. So far, only those who received the Pfizer vaccine are approved for a third booster shot. Overall, vaccination rates are now much higher than they were at the end of May.

The report found that the positive effects of vaccination extended to all racial groups — deaths fell by 21% to 25% — and that older people benefited not only from their own vaccinations but from high vaccination rates among younger residents in their surrounding communities. “This suggests that to protect Medicare beneficiaries, a high vaccination rate among those 65 and older on its own is not as effective as high vaccination rates among all adults,” the report said.

The study estimated that vaccinations led to 5,600 fewer deaths among nursing home residents, a group that was especially vulnerable during the first wave of the pandemic.

In this region, the report estimated that vaccines led to a reduction of 4,900 hospitalizations and 1,800 deaths in Pennsylvania; 3,900 hospitalizations and 1,400 deaths in New Jersey; and 600 hospitalizations and 200 deaths in Delaware.

Vaccines first became available in December 2020. At that point, 352,000 people in the United States had died of the new virus. According to the New York Times, deaths have now topped 700,000.

Texas and Hawaii were excluded from the new estimation model because they did not provide county-level estimates of vaccinations.