The study, conducted between April 6 and April 24 at Addenbrooke’s Hospital in Cambridge, found that 3 percent of the 1,032 asymptomatic National Health Service (NHS) workers tested were positive for COVID-19. A fifth of those workers told researchers they had not experienced any symptoms that are listed as common among COVID-19 patients.
“Focusing solely on the testing of individuals fitting a strict clinical case definition for COVID-19 will inevitably miss asymptomatic and pauci-symptomatic disease,” the study said. “This is of particular importance in the presence of falling numbers of community COVID-19 cases, as hospitals will become potential epicentres of local outbreaks.”
By Wednesday, 229,705 people in the U.K. had tested positive for COVID-19, with 27,496 virus deaths reported. According to reports by The Guardian, at least 100 health care workers in the U.K. died after contracting the virus, with government officials saying at least 27 of those were NHS workers.
As in many other parts of the world, testing in the U.K. has been limited as government officials have worked to secure the supplies needed for widespread testing. In late April, Health Secretary Mark Hancock announced an expansion of testing that included access for all NHS staff. However, researchers said more testing still needed to be done at health care facilities to prevent the asymptomatic spread of the virus, as the focus of testing among health care workers was still on those who exhibited symptoms.
The NHS staff members who worked in higher-risk parts of the hospital, including areas where COVID-19 patients were being treated, were three times more likely to contract the virus themselves in spite of their use of personal protective equipment (PPE), researchers said. With access to PPE limited at many facilities both in the U.K. and around the world, researchers said it was even more likely that health care workers could be positive for the virus and not know it, with an estimated 15,000 possible positive cases among NHS workers alone in the U.K.
In response to the results, Cambridge researchers suggested frequent testing for all health care workers, whether they present symptoms or not.
“Weekly testing of asymptomatic [health care workers] could reduce onward transmission by 16-23%, on top of isolation based on symptoms,” the study said.
“All staff need to get tested regularly for COVID-19, regardless of whether they have any sort of symptoms,” study co-author Dr. Mike Weekes said in a statement. “This will be vital to stop infection spreading within the hospital setting.”
