Professor James Moon, the chief investigator on the trial, said he had taken part in the study and also did not know whether he had tested positive for coronavirus. He has continued to work at the Nightingale Hospital in London.
“We took independent advice from virologists and our NHS Occupational Health team when designing the study,” Prof Moon said. “Their advice was that unless real time swab results were available, which they were clearly not given the constraints at the time, a result that was three to four weeks old would not, on balance, help patients or institutions.”
Studies in China suggest people can be infectious with coronavirus for up to 37 days, meaning healthcare workers could have still been shedding the virus after the results came back.
The study received ethical approval from the Health Research Authority (HRA) and the South-Central Oxford-A research ethics committee in particular. The decision was expedited and permission granted within just two days.
Dr Paquita de Zulueta, the Immediate Past President of The Medicine at the Royal Society of Medicine, said healthcare workers had been placed in a position in which they could not fulfil their duty of care to protect patients.
“Doctors, nurses and carers, in their personal accounts, often talk of their fear of unwittingly passing on the virus to vulnerable patients and of contributing to their death,” Dr de Zulueta said.
“They have been justifiably vocal in requesting regular testing to avoid this. Yet in this study some of the asymptomatic participants were likely to have been shedding the Covid-19 virus and potentially infecting patients and other individuals without their knowledge.
“Here we are justified – and indeed it behoves us – to ask for the rationale and ethical basis for the decision to not inform the healthcare workers who tested positive, thereby preventing them from fulfilling their professional duty to protect their patients from an avoidable risk of serious harm.”
This week, Cambridge University also published a trial looking at the number of infected staff at Addenbrooke’s Hospital over three weeks and found three per cent had the virus despite not having symptoms.
However, all trial participants who tested positive in the study were notified and told to self-isolate.
Dr Chris Smith, a consultant virologist at Addenbrooke’s, said: “This was an observational analysis, where you just measure something – in this case who has got coronavirus infection – rather than an interventional study where you change something and then look to see whether it makes a difference.
“As such, telling people that they are potentially infected and asking them to self-quarantine is the safe and ethical thing to do, and will make no difference at all to the observed pick-up rate in the hospital.”
West Midlands Ambulance Service has also been carrying out tests of staff and found that around three per cent were infected despite not having symptoms. However, those found to have the virus were sent home.
Prof Moon said although staff would not be told if they had coronavirus, the findings from the Barts study would be invaluable in the fight against the virus.
“The potential outputs of the study are enormous,” he said. “We are also looking at neutralising antibodies, the cell response and the serology, vital to understand if immune passports etc are to work after mild disease.
“This was about trying to balance benefits. We as a society really needed to understand this.
“We had no ability to analyse the results immediately because the NHS was needing PPE [personal protective equipment] for frontline care and the reagents for testing.
“I think knowing I had the disease might make me more complacent. I think there is a strong argument to keep the science clean without informing people.”