The Caritas Medical Centre has activated the Green Alert infectious disease response and stopped taking in new child patients as four more children have developed respiratory illness symptoms, bringing the total cases to 28.

After a meeting with the Centre for Health Protection today, Hospital Authority Chief Executive Dr William Ho said a series of new measures will be taken at the hospital immediately.

They include:

* refusing any new child patients and transferring new cases to Princess Margaret Hospital;

* transferring infected patients to an isolation ward;

* disinfecting the premises thoroughly; and,

* setting up an enquiry hotline (3408 7100).

Among the 28 infected patients, 11 still have fever and one has been admitted to intensive care in serious condition.

Initial investigations have ruled out SARS or common influenza, but further tests are needed to establish the source and type of infection.

The hospital has agreed to step up its co-operation with the authority and the centre. When more than three children in the same ward develop symptoms, the hospital will report the case to the centre immediately.