Six children have tested positive for para-influenza virus. The Hospital Authority said the two boys and six girls, aged seven to 15, in the Caritas Medical Centre's Developmental Disabilities Unit have been transferred to an isolation ward. Their conditions are stable.

Infection control measures have been stepped up at the unit, but visiting arrangements remain unchanged. All other child residents are under close surveillance.

The unit is a long-term hostel for severely mentally handicapped children.