More than 1 in 10 COVID-19 patients during the first wave of the pandemic contracted their infection while in the hospital, according to research findings based on an analysis from 314 U.K. hospitals.
Researchers analyzed the records of more than 82,000 COVID-19 patients in the U.K. whose symptoms started before Aug 1. 2020. They identified hospital-acquired infections by examining admission and symptom onset date, as well as other known information about SARS-CoV-2 incubation.
About 11.3 percent of COVID-19 patients across 314 hospitals contracted the infection after hospital admission, according to the findings published Aug. 12 in The Lancet. That jumped to nearly 16 percent by mid-May 2020.
"We estimate between 5,699 and 11,862 patients admitted in the first wave were infected during their hospital stay," researchers said. "This is, unfortunately, likely to be an underestimate, as we did not include patients who may have been infected but discharged before they could be diagnosed."
Residential community care hospitals and mental health hospitals had the highest proportions of hospital-acquired cases, at 61.9 percent and 67.5 percent, repsectively. At acute and general care hospitals, about 9.7 percent of cases were contracted in the hospital.
The study authors note there are a number of reasons why patients were infected in hospital settings.
"These include the large number of patients admitted to hospitals with limited facilities for care isolation, limited access to rapid and reliable diagnostic testing in the early stages of the outbreak, the challenges around access to and best use of [personal protective equipment,] our understanding of when patients are most infectious in their illness, some misclassification of cases due to presentation with atypical symptoms, and an under-appreciation of the role of airborne transmission," said Dr. Chris Green, study coauthor.
Researchers said the underlying reasons behind the findings need further investigation, and reassured that hospitals are safe for care.
"Rates are considerably lower a year on, and people should not be deterred from attending hospital if they are unwell," said Annemarie Docherty, PhD, coauthor of the study.