Infection preventionists rightly concerned about getting COVID-19 from patients can take some hope from a recent study in Infection Control & Hospital Epidemiology. While looking at how best to combat the disease, investigators in Hong Kong also wanted to find out what happened to 11 healthcare workers at the Queen Mary Hospital who, without proper personal protective equipment (PPE), treated patients confirmed to have COVID-19. Answer? Nothing. That is, the 11 healthcare workers—who had to be quarantined for 14 days—did not contract COVID-19. In addition, no hospital-acquired infections occurred after the first 6 weeks of the outbreak.
Investigators argue that their quick intervention and protocols helped to not only contain the disease but also track the exposure risks of the 413 healthcare workers who treated 1275 patients. “A bundle approach of active and enhanced laboratory surveillance, early airborne infection isolation, rapid molecular diagnostic testing, and contact tracing for healthcare workers (HCWs) with unprotected exposure in the hospitals was implemented,” the study states. “Epidemiological characteristics of confirmed cases, environmental and air samples were collected and analyzed.”
Unprotected exposure was defined as providing care with inappropriate PPE or caring for “patients who had stayed within the same cubicle of the index case regardless of the duration of exposure,” the study states. Investigators analyzed data on patients and healthcare workers at the hospital in the first 42 days after announcement of a cluster of pneumonia in China—that is for 42 days starting on December 31, 2019 and ending on February 10, 2020.
Hong Kong’s 43 public hospitals responded to the first sightings of what would eventually be named COVID-19, caused by the virus SARS-CoV-2, by immediately widening screening criteria to determine if patients may have come into contact with the coronavirus. When the screening process identified a patient at risk, the hospital immediately isolated the patients in negative pressure rooms or in a ward with at least a meter of space between patients. The hospitals put strict infection control measures in place, including PPE training, staff meetings about infection control, face-to-face education sessions for HCWs, and tighter hand-hygiene compliance oversight.
Transmission within families became a concern as 66% of confirmed cases diagnosed in Hong Kong were spread among family members. In 1 case, the asymptomatic patient turned out to be a 91-year-old lady. Citing a pediatric case, the investigators write that asymptomatic infection could “occur in the age of extremities.”
They urged further study about how COVID-19 might be transmitted by asymptomatic patients. However, they said that quick action proved pivotal.
“With the implementation of active and enhanced surveillance with progressive widening of screening criteria during the evolution of epidemic, we could recognize most of the confirmed case upon hospitalization and achieved zero nosocomial transmission in HCWs and patients within the first 6 weeks,” the study states. “However, our surveillance program may be challenged by the patients with mild symptoms. In the early publications, fever and cough were reported in 87% and 80% of patients, respectively, at the time of presentation.”