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COVID-19 Risk Factors for Healthcare Workers: Race, Ethnicity

Community, Not Workplace, Exposure Could Be Responsible; Medical Experts Now Seeking to Understand the Pandemic's Racial and Ethnic Disparities

Healthcare workers might not be so different from the general population in the factors that determine their risk of getting COVID-19. A new study led by Cedars-Sinai shows that healthcare workers are more likely to have antibodies to COVID-19 in their blood if they are African American or Latino or have hypertension.

Additionally, the study suggests that the community—rather than the workplace—is the more common source of coronavirus exposure.

The research, published online Feb. 12 in the peer-reviewed journal BMJ Open, was based on blood tests and a survey of more than 6,000 employees in the Cedars-Sinai Health System conducted starting in May 2020. During that first wave of the pandemic, about 4% of the employees were found to have antibodies to the SARS-CoV-2 virus in their blood, indicating they had been exposed to COVID-19.

"Our study shows that we started out last summer with a relatively low exposure rate to SARS-CoV-2," said Susan Cheng, MD, MPH, MMSc, associate professor of Cardiology at Cedars-Sinai and director of the Institute for Research on Healthy Aging in the Department of Cardiology at the Smidt Heart Institute. “This fact means the vast majority of our communities have remained vulnerable to infection, and therefore vaccination and continued vigilance are critical."

Of particular concern were the study's findings on race and ethnicity. Across the board, regardless of whether they had been diagnosed with COVID-19, blood tests showed that healthcare workers were significantly more likely to have antibodies to the SARS-CoV-2 virus if they were African American or Latino rather than of other racial or ethnic groups.

"These disparities underscore the ongoing, urgent need for us to understand why certain demographics and communities remain at higher risk in the pandemic than others," said Kimia Sobhani, PhD, medical director of the clinical core laboratories and associate professor of Pathology and Laboratory Medicine at Cedars-Sinai. "The reasons may well include structural and societal factors that we were unable to capture."

Sobhani was co-senior author of the study along with Cheng and Jonathan Braun, MD, PhD, professor of Medicine at the F. Widjaja Foundation Inflammatory Bowel and Immunobiology Research Institute at Cedars-Sinai.

Another significant finding was that having antibodies to the virus was related more to having had community-based exposure, including a household member previously diagnosed with COVID19, than to workplace exposure.

"Our data show that public health measures work," said study co-author Peggy Miles, MD, associate professor of Medicine and medical director of Employee Health Services at Cedars-Sinai. "Our workers are taking care of the sickest people, including high-risk patients, and yet we see very little transmission of coronavirus in the hospital." Miles was a major force in developing the original concept of the research project.

The study also found:

  • Not all workers with antibodies to SARS-CoV-2 reported experiencing symptoms. But among those who did, the most common symptom was loss of smell.
  • The degree of antibody response to the virus was related not only to the magnitude of exposure and severity of illness but also to the presence of hypertension, or high blood pressure—for reasons that are not yet clear.
  • Asthma patients had lower antibody levels that were less often above the threshold of detection used in the study. The reason was unclear.

The investigators are currently following up on the BMJ Open findings by tracking SARS-CoV-2 antibody levels in both patients and healthcare workers over time to see how they change, especially in response to vaccines. "We hope that antibody-level patterns will signal a durable acquired immunity that persists over time as we try to make our way out of this pandemic," Braun explained.

The BMJ Open report and related research are part of the Coronavirus Risk Associations and Longitudinal Evaluation (CORALE) study conducted by a network of clinicians and scientists from multiple institutions, primarily in Southern California.

CORALE is conducting additional research projects for the national Serological Sciences Network, or SeroNet, a collaborative of universities, cancer centers and laboratories formed by the National Cancer Institute of the National Institutes of Health. The goal is to advance knowledge of immunology and COVID-19 in the U.S., and Cedars-Sinai is one of just eight SeroNet Centers of Excellence in the country—institutions that have been awarded NCI grants to conduct multiple research projects for the initiative.

Funding: Research reported in this article was supported in part by Cedars-Sinai, the Erika J. Glazer Family Foundation; the F. Widjaja Family Foundation; the Helmsley Charitable Trust; and the National Cancer Institute under grant number U54-CA26059 and the National Heart, Lung, and Blood Institute under grant K23-HL153888, both from the National Institutes of Health.

DOI: 10.1136/bmjopen-2020-043584

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