HONG KONG: Wearing face masks and keeping hands hygienically clean has proven an effective method of reducing the transmission of influenza within households, a university study revealed yesterday.

The University of Hong Kong (HKU) Li Ka Shing Faculty of Medicine, Department of Community Medicine and School of Public Health conducted a study on 259 families in which index cases of confirmed influenza had been recorded.

They were classified in three groups; one became the control group and the other two were intervention groups.

One group was given liquid hand soap and alcohol hand rubs, and another provided with hand wash plus surgical face masks.

In the seven-day follow-up, the university found that the chance of household members becoming infected was reduced by about 67 percent among those who adopted both the face masks and good hand hygiene within 36 hours of the onset of symptoms in the index case.

"If the household contacts can apply these measures as soon as possible after one family member is confirmed to be infected, theoretically this can tremendously reduce the chance of infection," said Ip Kai-ming, clinical assistant professor.

He added some of the family members who took part in the study were reluctant to wear face masks, which means that the actual efficacy of the measures may have been underestimated by the analysis.

The HKU said as the findings are drawn from analysis within a household setting, it would require further studies to assess the effectiveness of the hand hygiene and face masks in the community such as schools and public transport.

There were 232 newly confirmed cases of A (H1N1) swine influenza yesterday, bringing the total number of cases to 4,504. Three deaths from the virus have been recorded so far. Four patients are still in critical condition.

The government has ceased measures requiring compulsory hospitalization and isolation of patients infected with human swine flu. Patients are asked to isolate themselves at home until they stage a full recovery.

(HK Edition 08/05/2009 page1)