More than 100 pregnant women underwent extra blood tests after three medical staff from Queen Mary Hospital were found to have a virus that can cause miscarriages.
The trio - a nurse and two doctors from the hospital's obstetrics and gynaecology ward - were infected with parvovirus B19, which causes fever, fatigue, pains in joints and rashes.
Doctors said the virus, though common, was a risk for pregnant women of 24 weeks or less and for people with weak immune systems.
'Pregnant women can pass the virus to the babies and this may result in a miscarriage. The chance of infection is one per cent or less,' said consultant microbiologist Dr Que Tak-lun.
The virus does not cause congenital abnormalities.
Patients with a history of contact with medical staff within the incubation period of four to 20 days were being screened.
Dr Que said the virus could pass to people 'silently', because symptoms would only emerge after the patients began to recover. 'There are no symptoms when a person is harbouring the virus,' he said.
