Risk for nosocomial COVID-19 low under strict control measures, study suggests
In the early months of the pandemic, a Boston hospital with an infection prevention program that included dedicated COVID-19 units with airborne infection isolation rooms recorded just two cases of nosocomial COVID-19, a study found.
Researchers said the results “suggest that overall risk of hospital-acquired COVID-19 was low and that rigorous infection control measures may be associated with minimized risk.”
The infection control program at Brigham and Women’s Hospital also included personal protective equipment (PPE) donning and doffing monitors, a universal masking policy, restricted visitation, and liberal testing of symptomatic and asymptomatic patients, according to the study.
“Our study demonstrates that a multifaceted infection control program based on U.S. CDC guidance can successfully minimize the risk of nosocomial transmission of SARS-CoV-2 to hospitalized patients,” Chanu Rhee, MD, MPH, an infectious disease and critical care physician and associate hospital epidemiologist at the hospital, told Healio. “These findings, especially if replicated at other hospitals, should provide reassurance to patients as some health care systems re-open services and others continue to face COVID-19 surges.”
Rhee and colleagues conducted a cohort study that included 9,149 patients admitted to Brigham and Women’s Hospital over 12 weeks from March 7 to May 30 to determine the incidence of hospital-acquired COVID-19. They reviewed medical records for patients who tested positive for SARS-CoV-2 on hospital day 3 or later, and within 14 days of discharge.
Of the patients, 697 were diagnosed with COVID-19. Only two of the cases were determined to be hospital-acquired — one patient who likely was infected by a presymptomatic spouse before the implementation of visitor restrictions, and one patient who developed symptoms 4 days after a 16-day hospitalization who did not have any known exposures in the hospital.
Rhee said the results were “extremely reassuring” to the hospital’s staff and patients.
“I was a little surprised at how few cases of nosocomial COVID-19 we identified despite the fact that our hospital cared for a large number of COVID-19 patients,” Rhee said. “When the pandemic began, we really didn’t know for sure whether or not our infection control measures would be adequate in preventing spread of the virus around the hospital, as we had never dealt with something similar before.”
Results from the study may be generalizable to other hospitals “insofar as the infection control measures at Brigham and Women’s Hospital were informed by CDC guidance,” Rhee said.
Rhee noted that the efficacy of infection control measures is influenced by several factors, including staff policy adherence, the availability of PPE and airborne infection isolation rooms, surge capacity and testing capacity.
One of the study’s limitations was that it did not determine what specific infection control measures at the hospital were “most critical,” according to Rhee.
“It will be particularly important in future studies to address the relative importance of some infection control components that we implemented, but that may not be feasible at all other hospitals, such as using airborne infection isolation rooms for all patients with COVID-19 or using trained observers for PPE donning and doffing 24-7,” Rhee said. “In addition, our study focused on nosocomial infections among hospitalized patients but did not examine infections among healthcare workers. We believe that this is a very important topic that warrants a separate, detailed analysis.”