Real-World Data Shows Benefit of Vaccinating Healthcare Workers

Real-world data collected at a large medical center showed that vaccinating healthcare workers reduced the number of required isolations and quarantines by more than 90 percent.

Recently published in the New England Journal of Medicine, the data comes from the University of Texas Southwestern Medical Center, which initiated a program in mid-December to vaccinate its frontline employees. Healthcare workers were among the first groups to be eligible for vaccination.

"Real-world experience with SARS-CoV-2 vaccination at UT Southwestern demonstrated a marked reduction in the incidence of infections among our employees, preserving the workforce when it was most needed," said Daniel K. Podolsky, MD, president of UT Southwestern and senior author.

During the first 31 days of vaccinations becoming available, UT Southwestern provided a first dose to 59 percent of roughly 23,000 employees. Thirty percent were able to be fully vaccinated during that time.

The data showed that after administering vaccinations, 1.5 percent of employees became infected with COVID-19. Infection rates were highest – at 2.6 percent – among nonvaccinated employees, while they were lowest – 0.5 percent – among those fully vaccinated.

"Our ability to quickly vaccinate a majority of our workforce in the midst of what became the largest surge to date in the region made a critical difference in ensuring we were able to continue providing top-flight care while health systems were strained," said John Warner, MD, executive vice president for health system affairs at UT Southwestern.

Researchers also saw advantages among partially vaccinated individuals. From January 9, the actual number of positive tests among all UT Southwestern employees was consistently lower than the number projected.

The data also demonstrates the ongoing need to address vaccine hesitancy, with UT Southwestern now approaching 70 percent immunization among its workforce.

“In light of this real-world experience clearly demonstrating the effectiveness of immunization, further understanding of the reticence of some individuals to take advantage of vaccination bears even greater importance," said first author William Daniel, MD, vice president and chief quality officer at UT Southwestern.

To reduce vaccine hesitancy, UT Southwestern has provided educational outreach to community groups and businesses and developed extensive online resources like Q&As and blogs. Additionally, the institution is preparing to launch a multilingual public service announcement campaign to help educate diverse communities about vaccination and address issues of hesitancy.

"It is important to reach out across multiple platforms to effectively address people's questions so that we can continue to make progress on vaccine hesitancy," said Marc Nivet, EdD, executive vice president for institutional advancement at UT Southwestern.

The results from UT Southwestern coincide with a separate analysis conducted by researchers at University of California San Diego School of Medicine and the David Geffen School of Medicine at UCLA.

In a letter to the New England Journal of Medicine, the team reported COVID-19 infection rates for a cohort of healthcare workers previously vaccinated for the virus.

"Because of the compulsory daily symptom screening of healthcare personnel, patients, and visitors, and the high testing capacity at both UC San Diego Health and UCLA Health, we were able to identify symptomatic and asymptomatic infections among healthcare workers at our institutions," said co-author Jocelyn Keehner MD, an infectious disease fellow at UC San Diego School of Medicine.

"Moreover, we were able to describe the infection rates in a real-world scenario, where vaccine roll-out coincided with a surge of infections. We observed a low overall positivity rate among fully immunized health care workers, supporting the high protection rates of these vaccines."

The team looked at pooled data from healthcare workers who received either the Pfizer or Moderna vaccines between December 16, 2020 and February 9, 2021. Within this group, 379 tested positive for COVID-19 at least one day following vaccination, with 71 percent testing positive within the first two weeks after the first dose. Thirty-seven healthcare workers tested positive after receiving two doses.

"There are several possible explanations for this elevated risk," said co-author Lucy E. Horton, MD, MPH, associate professor in the Division of Infectious Diseases and Global Public Health at UC San Diego School of Medicine and medical director of the UC San Diego Health Contact Tracing Unit.

"First, the healthcare workers surveyed have access to regular asymptomatic and symptomatic testing. Second, there was a regional surge in infections overlapping with vaccination campaigns during this time period. And third, there are differences in the demographics of healthcare workers compared to participants in the vaccine clinical trials. Healthcare workers tend to be younger and have a greater overall risk of exposure to SARS-CoV-2 in the community."

Increased rates of infection have been strongly linked to behaviors that heighten risk of exposure, including going to bars or restaurants without adequate masking and physical distancing. While researchers found that risk of infection 14 days after second dose was rare, it is still possible.

"It underscores the critical importance of continued public health mitigation measures (masking, physical distancing, daily symptom screening and regular testing), even in highly vaccinated environments, until herd immunity is reached at large," said corresponding author Francesca Torriani, MD, professor of clinical medicine in the Division of Infectious Diseases and Global Public Health in the UC San Diego School of Medicine and program director of Infection Prevention and Clinical Epidemiology at UC San Diego Health.

The studies represent the critical role of real-world data as the country begins to open again and the healthcare industry aims to address vaccine hesitancy.