Testing at a hospital that closed to new admissions because of a high number of coronavirus cases has found approximately 6% of staff are infected without showing symptoms.
Weston General Hospital in Weston-super-Mare, Somerset, stopped accepting new patients from 8am last Monday to maintain patient and staff safety.
All inpatients have been tested for Covid-19 and no new cases have been identified, the hospital said.
The majority of the 1,700 staff working at the hospital have been tested, with results indicating that approximately 6% are asymptomatic and infected.
Any members of staff who have tested positive have self-isolated and it is hoped that those who have not yet been tested will be by the end of Saturday.
Dr William Oldfield, medical director at University Hospitals Bristol and Weston NHS Foundation Trust, said: “The signs are encouraging.
“The results from our inpatient testing have identified no new cases of Covid-19, which suggests the actions we have taken to control the situation are working.
“We will retest all our inpatients again next week, and if the results continue to show no new cases, this would indicate no in-hospital transmission of the infection.
“We will also repeat testing of all staff at the hospital again next week. The results from this will indicate whether the staff working in the hospital are remaining free of infection.
“We are continuing to safely discharge patients as appropriate when they no longer need our care, and as patients are discharged areas are being deep cleaned to get the hospital ready to reopen.”
In an interview with BBC Points West on Friday, Dr Oldfield said it was too early to say what the “root cause” of the outbreak was.
John Penrose, MP for Weston-super-Mare, tweeted: “Everyone was astonished by the number of staff who were infected, but not showing symptoms.
“Closing the hospital to new admissions to protect patients and staff was absolutely the right decision.”
North Somerset Council contacted all schools in the area advising them to delay reopening until June 8 as a precautionary measure.
It said a “comprehensive data set” on the hospital outbreak was required and analysis on it completed before schools in North Somerset could reopen to wider groups of pupils.
Mike Bell, deputy leader and executive member for public health at North Somerset Council, said: “We are encouraging schools to stay closed for a further week.
“We think it is sensible to wait until we have a clearer picture of how the virus might be spreading in our community before they open their doors to a wider group of pupils and parents.
“There is currently no evidence to suggest any increased risk of infection in the community as a result of the outbreak at the hospital, however, we need to have sight of all the data from the hospital alongside community indicators so that our public health team and colleagues in Public Health England can review the full implications of the outbreak.
“This is purely a precautionary measure, but we want to be satisfied that the work is complete before we advise schools to re-open more widely.”