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The prevalence of SARS-CoV-2 antibodies was only slightly higher among healthcare personnel (HCP) compared with the general public after the HCPs were given personal protective equipment (PPE), researchers have found.

Voluntary SARS-CoV-2 antibody screening at a large healthcare system found that 13.7% of HCPs tested positive for the antibodies, only slightly higher than the prevalence in the general adult population in that state.

There was very little difference in antibody seroprevalence when sex, race, ethnicity, and age were factored in, as well as whether a person worked in an area such as an intensive care unit or behind the reception desk, the researchers write.

Senior author Karina Davidson, PhD, senior vice president at Northwell's Feinstein Institutes for Medical Research, told Medscape Medical News the results indicate that PPE works.

Joseph Moscola, PA, MBA, head of human resources for Northwell Health in New Hyde Park, New York, and colleagues published their findings online August 6 in a research letter in JAMA.

Davidson said the team was very surprised that the positive rate was only 13.7% "even though some spent 18 hours a day around COVID-positive patients."

For comparison, the authors write, a New York State report showed that 12.3% of the general New York state adult population tested positive for COVID-19 antibodies. Another preliminary report from Governor Andrew Cuomo's office showed 10.5% of the NYPD and 17.1% of FDNY and EMT members tested positive for antibodies.

Eric Topol, MD, founder and director of the Scripps Research Translational Institute, and editor-in-chief of Medscape, said the strength of this study was its size. According to the authors, 46,117 workers (65.1% of the 70,812 invited to participate) were tested as of June 23. But he cautioned against reading too much into one report.

"I've looked at a lot of these seroprevalence studies among healthcare workers and I'm not sure this one makes a unique contribution," he told Medscape Medical News.

He said other studies have shown different rates of seropositivity for healthcare workers and for New York's general population.

Topol added that this study did not make a definitive link between the role of PPE and seroprevalence. Particularly unclear, he said, was what kind of PPE the workers wore.

Davidson told Medscape Medical News that Northwell, like other health systems across the country, changed what PPE was used over the study period as supplies ran out and were replenished.

Topol pointed out, and the authors acknowledge, that a study limitation was that testing was voluntary (56% participated) and could open the door for bias. Perhaps the people who volunteered were those most concerned about their health, which could affect results, he explained.

Davidson said leaders at Northwell, the largest health system in New York, asked healthcare workers what would help them most as they encountered tens of thousands of patients.

She said the workers reported that lack of free, convenient, fast testing was a top concern, especially at the beginning of the study period, from April 20 to June 23.

The health system then offered free testing at all locations, offering night and weekend hours and drive-through service regardless of symptoms.

Although there was little difference in seroprevalence in the demographic breakdowns, one category — suspicion of having been exposed — stood out as a predictor, Davidson said.

Workers were asked, "Do you believe you were infected with COVID-19?" Those who had a high suspicion that they were infected were much more likely to have seroprevalence (relative risk, 1.23; P < .001).

Davidson said asking that question of healthcare workers, rather than, for instance, whether they currently have a fever or have had a fever recently, may be a better predictor of who should get tested.

The final consented sample of 40,329 had a median age of 42 years and 73.7% were women. Participants included 16.0% Black, 0.8% multiracial, and 14.0% Hispanic healthcare workers; 28.4% were nurses and 9.3% were physicians.

Marcia Frellick is a freelance journalist based in Chicago. She has previously written for the Chicago Tribune, Science News and Nurse.com and was an editor at the Chicago Sun-Times, the Cincinnati Enquirer, and the St Cloud (Minnesota) Times. Follow her on Twitter at @mfrellick

The authors have disclosed no relevant financial relationships.

JAMA. Published online August 6, 2020. Research letter

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Cite this: Antibody Prevalence Similar for NY Healthcare Workers, Public - Medscape - Aug 10, 2020.