Study of COVID-19 infection rates among CHOC’s Emergency Department personnel suggests most got virus through community exposure

A team from CHOC has published original research on the prevalence of COVID-19 infection among its Emergency Department workers during the early stages of the pandemic.

A key finding of the study, called PASSOVER (Provider Antibody Serology Study of Virus in the Emergency Room), suggests that most infections were transmitted through community exposure rather than co-workers, although the study stopped short of drawing a definitive conclusion based on the relatively small sample size of workers who agreed to be tested for SARS-CoV-2.

Researchers observed a seroconversion rate of about one new positive case every two days during the period from April 14-May 13, 2020, during which 143 CHOC ED personnel were repeatedly tested for the virus. They included doctors, physician assistants, nurse practitioners, nurses, medical technicians, secretaries, monitor technicians, and additional administrative staff.

“The acquisition of seropositivity in our study group appeared to follow a linear trend, which is not consistent with the exponential rate of growth that would be expected for transmission within a closely interacting group of people,” the study concludes.

The research project, the results of which were electronically published on April 9, 2021 in the Western Journal of Emergency Medicine, was led by Dr. Theodore Heyming, chair of emergency medicine at CHOC, and Dr. Terence Sanger, a physician, engineer, and computational neuroscientist and vice president, chief scientific officer at CHOC, and vice chair of research for pediatrics at the UCI School of Medicine. The other co-authors of the study are John Schomberg, PhD, CHOC’s Department of Nursing; and Aprille Tongol, Kellie Bacon, and Bryan Lara, all of CHOC’s Research Institute.

The study noted that there is limited data that is publicly available on the seroprevalence of SARS-CoV-2 among healthcare workers. Another of the report’s key findings was that rapid antibody testing may be useful for screening for SARS-CoV-2 seropositivity in high-risk populations such as healthcare workers in the ED.

In the CHOC study, blood samples were obtained from asymptomatic ED workers by fingerstick at the start of each shift from April 14-May 13, 2020. Each worker’s blood sample was obtained every four days until the end of the study period. In addition, a nasopharyngeal swab (NPS) was collected from each participant on the date of study entry.

At the time of the study, 35 percent of the participants had known exposure to a COVID-19-positive individuals within the preceding five days.

Depending on the method used for analysis, the seroprevalence of SARS-CoV-2 among CHOC’s pediatric ED workers ranged from 2 percent to 10.5 percent – levels that were slightly higher than those reported for the local general population, the study found.

“This study would benefit from replication at additional sites that draw from larger samples of ED staff,” the report says.

Learn more about CHOC’s COVID-19 vaccine clinic.

CHOC study shows reduced risk of emergency department COVID-19 infection

A new CHOC study that could help calm public fears about contracting COVID-19 shows that asymptomatic healthcare professionals who work in a community with a low prevalence of the disease and who undergo daily health screenings are unlikely to be carriers of the coronavirus that causes the disease.

Findings of the study, one of the first of its kind and conducted during California’s projected peak of coronavirus-related use of hospital resources, shine an encouraging light on a topic where there are currently limited data available.

CHOC’s study tested patient-facing staff at its Julia and George Argyros Emergency Department during a two-week period in April 2020, using a Polymerase chain reaction (PCR) test for COVID-19 viral RNA. Subjects were asymptomatic and had no fever, as all employees undergo daily pre-shift health and temperature screenings prior to entering the hospital. Testing found just one of 145 subjects was positive for COVID-19, and contact tracing showed that this person was not responsible for any further transmission of infection.

With these findings indicating that strict screening measures in a hospital serving a community with a lower prevalence of COVID-19 are effective in preventing the spread of the disease, the study could also offer some comfort to people who may have been reluctant to seek medical care for themselves or their children because they fear contracting COVID-19 in a healthcare setting. 

“We are encouraged by the results of the study and trust that our community will be reassured to know that the chances of acquiring COVID-19 during a visit to a pediatric emergency department can be lower than during routine activities,” said study co-investigator Dr. Terence Sanger, CHOC’s vice president of research and chief scientific officer. “We continue to urge them to seek prompt expert care for themselves and their children when the need arises.”

Hospitals nationwide have reported a significant drop in emergency department visits for major acute conditions. Patients may seek medical attention too late for adequate treatment, which could have serious, even fatal, consequences.

Preliminary data from California suggest that while healthcare workers represent 10% of all known COVID-19 cases in the state, only 18% of those cases were known to be acquired in a healthcare setting. This indicates the workers likely contacted the disease outside of the healthcare setting.

The low rate of infection in CHOC’s emergency department could be attributed to many factors, including the lower percentage of infection in the surrounding community, as well as people in the community following safety guidelines including social distancing and wearing masks.

Additionally, healthcare workers in a pediatric setting might be expected to have a lower risk of infection than those in an adult healthcare setting due to a lower rate of high-risk aerosolization procedures such as intubation in younger patients.

“We take every precaution we can to prevent the spread of COVID-19 in CHOC care settings,” said Dr. Theodore Heyming, medical director of CHOC’s emergency department and study co-investigator. “While the effects of the coronavirus continue to be devastating, this report offers a ray of hope that brave healthcare workers can continue to administer care to their patients without the added burden of putting themselves or the people they care for at further unnecessary risk.”

Also contributing to the study were Aprille Tongol, a CHOC research administrator; Jennifer MacLean, a CHOC nurse practitioner; and multiple staff from the CHOC Research Institute.

Learn more about the CHOC Research Institute.

CHOC study aims to determine COVID-19 antibodies present in Emergency department staff

A CHOC Hospital study could determine how many patient-facing clinicians and staff in its emergency department have COVID-19 fighting antibodies, easing concerns of asymptomatic carriers exposing others to the virus in an acute care setting.

Using rapid serological testing, the monthlong study will determine the prevalence of viral exposure and incidence of new exposure among staff at the Julia and George Argyros Emergency Department at CHOC Hospital.

Serological blood testing looks for antibodies developed by the body to fight infection. Antibodies indicate the likelihood of past or recent infection or exposure. While researchers are still learning about COVID-19, it is also possible those who have been exposed to the virus and recovered have produced antibodies to protect them from the infection.

“While COVID-19 antibody screening is in its infancy, CHOC is pleased to help share data and contribute to this important conversation as the world’s scientific community unites in a race toward universal testing, antiviral treatment, and the development of a vaccine in order to permit a scientifically-based return to  normalcy,” said study co-principal investigator Dr. Terence Sanger, CHOC’s vice president of research and chief scientific officer.

Dr. Terence Sanger, study co-principal investigator and CHOC’s vice president of research and chief scientific officer.

Under the study, participants will undergo rapid antibody serology testing for immunoglobin G (IgG) and immunoglobin M (IgM) against COVID-19 novel coronavirus through a simple finger prick once per shift, with results available in three minutes. Additionally, all subjects will undergo viral RNA testing on their first day of the study, as well as on any day that they show IgM positive for antibodies.

In early results, all 107 people tested so far had negative results on reverse transcriptase polymerase chain reaction (RT-PCR) tests, a COVID-19 test, and all were negative for IgGs against COVID-19. Two tested positive for IgM but their viral RNA testing was negative.

As the study progresses, up to 250 subjects are expected to enroll total, with about 100 participants being tested each day.

Secondary outcomes include determining a correlation between antibody serology and DNA testing for acute infection, test-retest reliability of serology testing, evidence for direct transmission of infection between healthcare workers, and potential for reinfection in previously infected convalescent patients. 

Antibody screening could become an additional element of  CHOC’s toolkit in protecting patients, families, physicians and staff against COVID-19. Already, the hospital conducts health screenings, requires appropriate masks and personal protective equipment and practices social distancing, in addition to stringent cleaning practices.

All combined, an additional critically important benefit of the study would be the establishment of a “safe zone” in the emergency department by reducing concerns that an asymptomatic staff member or clinician could transmit the disease to a patient seeking care, or their family, despite CHOC’s strict safety and infection prevention precautions.

Hospitals and health systems nationwide are reporting declining emergency department visits, attributed to patients delaying care out of fear of contracting COVID-19 in the facility. For example, more than half of respondents in a recent NRC Health survey have delayed healthcare for themselves or someone in their home because of the virus, and 60 percent of respondents thought there was an elevated risk when visiting their providers.

Suggesting the national trend has impacted CHOC, its current emergency department volume is about 25 percent less than typical this time of year, yet patient acuity is much higher than typical.

“Seeking prompt and expert care for children in emergent situations is critically important – especially during a pandemic,” said Dr. Theodore Heyming, medical director of CHOC’s emergency department and principal investigator of the study. “We understand how frightening COVID-19 is for parents and children alike. We are excited by the possibility that this study could further prove CHOC as a haven for worried parents, and a source of safe and expert pediatric care during this outbreak – and always.”

Dr. Theodore Heyming, medical director of CHOC’s emergency department and principal investigator of the study.

The study, expected to run through mid-May, is aided by WytCote, an Irvine-based technologies solutions company that has enabled access to testing kits from Jiangsu SuperBio Medical Inc.

“This pandemic is impacting all our communities and WytCote recognized that gaining access to such testing could play a critical role towards limiting the spread of the virus. We are pleased to be partnering with CHOC to support the testing and use of this new coronavirus antibody test,” said Frank Gomez, WytCote’s CEO/Founder.

Learn more about the CHOC Research Institute