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Assessing CHOP Employees’ Exposure to the Coronavirus on a Community Level

Published on May 18, 2020 in Cornerstone Blog · Last updated 1 year ago


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Brian Fisher, DO, MPH, MSCE, leads a study that assesses the immune response to SARS-CoV-2 among CHOP employees working in various settings across the Hospital during this pandemic.

mccannn [at] (By Nancy McCann)

Editor's Note: Recruitment for this study is closed, after successfully enrolling about 2,000 employees. The study team continues to have follow-up visits, but they are no longer accepting new subjects.

A study team of Children’s Hospital of Philadelphia researchers wants to learn what the worldwide COVID-19 phenomenon means closest to home in the community of employees they work with and live near.

Brian Fisher, DO, MPH, MSCE, associate chair of Research in the Department of Pediatrics at Children’s Hospital, and co-investigator Jeffrey Gerber, MD, PhD, associate chief clinical research officer at CHOP’s Research Institute, are leading a study on the serostatus among the employees of CHOP. They will assess the immune response to SARS-CoV-2, which is the virus that causes COVID-19, among CHOP employees working in various settings across the Hospital during the pandemic.

Their goal is to try to detect the number of people who had either symptomatic or asymptomatic infection, in order to get a sense of how many people in the CHOP community have developed antibodies to SARS-CoV-2.

While there is not yet any evidence that people who have recovered from COVID-19 are immune from a second infection, Dr. Fisher said, “learning which groups in our workforce have developed antibodies to SARS-CoV-2 will help inform risk stratification for future exposure. As this pandemic will continue for months, if not longer, this will be critical information to understand how we can best protect our workforce at CHOP going forward."

Help Wanted: Up to 3,000 CHOP Employees

This prospective cohort study is open to any CHOP employees over 18 years-old who works at a CHOP inpatient or outpatient care location. The research team, including clinical research coordinator Anna Sharova, is looking to recruit not only frontline healthcare workers but also those who do jobs that may not involve direct patient contact, such as providing security, environmental, and food services.

“This study is meant to be inclusive of healthcare workers and other CHOP employees to provide us a better sense of who might have been exposed to the virus.” Dr. Fisher said. “The risk to employees that do not have direct patient contact is likely to be much lower, but assessing these employee groups can give insights on how exposures outside the hospital may impact serostatus.”

The study will collect blood samples from research study participants at designated intervals over a 12-month period, and will evaluate the specimens for presence and function of SARS-CoV-2 antibodies. The team aims to describe the evolution of seroconversion — the transition from negative to positive antibody presence — and assess for factors such as occupation and work site that may predispose to seroconversion. A biorepository of residual blood specimens from the subset of study participants that consent to future specimen use will be established for potential future research.

“We hope this study will help others outside of CHOP learn more about how a workforce at a pediatric institution may be exposed to this virus,” said Dr. Gerber, who is an associate professor of Pediatrics and Epidemiology in the Perelman School of Medicine at University of Pennsylvania.

Study Design

The recruitment strategy will be a staged approach. The initial recruitment communications aim to engage employees in high-risk areas, such as the Pediatric Special Treatment Unit, Special Isolation Unit, Emergency Department, and the Pediatric Intensive Care Unit. These employees are believed to have the highest likelihood of contact with COVID-19. After these employees are enrolled the study team will progress to other areas of the hospital workforce.

CHOP employees who consent to participate in the study will answer a pre-visit questionnaire to gather demographic and occupational information, medical and social history, and specific details regarding the location of their work. During the initial study visit, blood specimens will be collected via venipuncture at the Center for Human Phenomic Sciences (CHPS). All study participants will be asked to return to CHPS over a one-year period, where additional blood research draws will be conducted. During the first two months, blood will be drawn once each month, and then at six and 12 month intervals from the enrollment date.

With funding from CHOP Research Institute, the serology testing will be performed in the lab of Scott Hensley, PhD, associate professor of Microbiology in the Perelman School of Medicine at Penn. In order to quantify the number of antibodies present, Dr. Hensley’s lab uses a technique called enzyme-linked immunosorbent assay, or ELISA. This is a slower but more precise method than the commercially available rapid tests, according to an article in Penn Today.

“The goal for the dense sampling early on is to try to capture at what point subjects may be seroconverting to the virus while we’re amidst the high exposure window that we’re in right now,” said Dr. Fisher, who is also on faculty in the Perelman School of Medicine at Penn. “We’ll follow folks out to the six month and 12 month window to assess the durability of the response, or for those who don’t respond in the first two months to see if they develop antibodies further out.”

Test Reliability Before Test Results

Serology testing studies have ignited excitement across the globe because they are proposed as a mechanism of understanding who is protected and who is not protected against SARS-CoV-2. However, it is not yet known if antibodies that recognize this specific coronavirus, meaning they were previously infected with the virus — will provide protection against future exposures.

“These tests are brand new; there’s much we still need to learn,” Dr. Fisher said. “They may detect antibodies, but are those antibodies actually protective against the virus? Do they neutralize the virus? We need to prove how well these tests work before we start telling people their individual results.”

With that in mind, the study team will be taking a methodical approach to testing this novel serologic assay and will not release individual results to study subjects — yet. In order to understand how well the test operates, Dr. Fisher has proposed to analyze the results from the first enrollees, and if the results look reassuring and valid, he will ask the Institutional Review Board for approval to release individual results.

“If we think about CHOP’s employee network as a community of individuals in the Greater Philadelphia area, then we can assess this population to get a better sense of how significant the exposure to SAR-CoV-2 is at a community level,” Dr. Fisher said. “Describing the evolution of the seroprevalence of this virus among our healthcare workers and employees now, and as the pandemic progresses, will be meaningful to our and other healthcare systems.”