Antibody rates among Black and Hispanic New Yorkers are double those of others, new estimates show.

New York City Health officials estimate that nearly a quarter of adult New Yorkers were infected with the coronavirus during last spring’s disastrous wave, and that the population of blacks and Hispanics was even higher.

The estimates, based on antibody test results for more than 45,000 residents of the city last year, suggest that black and Hispanic New Yorkers were twice as likely to have antibodies to the coronavirus as white New Yorkers – evidence of previous infection.

Hispanic New Yorkers had the highest rate, about 35 percent testing positive for antibodies, according to the study, which included officials and researchers from the city’s Department of Health and the National Institute for Occupational Safety and Health. Among black New Yorkers, 33.5 percent had antibodies. For Asian New Yorkers, the rate was around 20 percent. For white New Yorkers, the rate was 16 percent.

Population antibody screening has become a useful way to determine what percentage of people were infected and which groups were most at risk, especially since limited testing for the virus was done during the first wave.

The new paper, accepted by the Journal of Infectious Diseases, has significant limitations: Of the 45,000 New Yorkers in the study, fewer than 3,500 were black, a gross underrepresentation. And participants were partially recruited through online advertising, which the study’s authors believe may have attracted people who believed they had been exposed to Covid-19.

However, the study adds to the experts’ understanding of the disproportionate toll the pandemic has put on blacks and Latinos.

The results also come from an effort to vaccinate more people in the United States. A recent survey by the Kaiser Family Foundation found that the number of Americans, especially black adults, who want to get vaccinated has continued to rise. According to an analysis by the New York Times last month, blacks were still vaccinated at half the rate of whites. The differences are particularly alarming as blacks, Latinos, and Indians die twice as often as whites.

In New York City, about 44 percent of white adults have received at least one dose of a Covid-19 vaccine, according to the city, while 26 percent of black adults and 31 percent of Latino adults have.

Experts and community leaders across the country say the lower overall vaccination rates are linked to technological and language barriers and inequalities in access to vaccination sites. Other factors include misinformation on social media and reluctance to get vaccinated. Reluctance among African Americans, according to experts, may be linked to long-standing distrust of medical facilities that have long been mistreating blacks.

The latest data from New York “shows how frontline workers carried the brunt of the first wave of the pandemic,” said Dr. Wafaa El-Sadr, professor of epidemiology and medicine at Columbia Mailman School of Public Health, who was not involved in the study. It found that many jobs with higher exposure – such as grocery store clerks, childcare workers, and transit workers – have comparatively fewer white workers.

“These were the people who didn’t have the luxury of being able to work virtually,” she said.

Dr. Kitaw Demissie, dean of the School of Public Health at SUNY Downstate Medical Center in Brooklyn and not involved in the study, noted that household overcrowding may also have contributed to different rates of infection. Some predominantly Latin American districts, which were particularly badly affected in the first wave, showed a high rate of displacement of households.

According to a database from the New York Times, more than 32,000 people have died of Covid-19 in New York.