The Centre for Health Protection warns that Hong Kong is entering the summer influenza season, with rising flu cases observed recently.

From June 18 to 28, outbreaks occurred in 20 institutions. Consultation rates for influenza-like illnesses in private doctor clinics rose from 56.6 to 70.7 for every 1,000 visits, while at Government outpatient clinics the rate climbed from 5.2 to 7.1.

Influenza viruses isolated by the centre's laboratory are also on the rise, with influenza viral detections jumping from 105 to 176.

The predominant strains detected are influenza A H3N2 (Wisconsin) and influenza B (Shanghai). The vaccine strains recommended in the 2006-07 Government Influenza Vaccination Program matches influenza A but not B. However, some degree of immunity against B is expected in the population as it has been circulating since 2002.

The centre called on people to take measures to prevent flu and other respiratory illnesses. Schools, nurseries and kindergartens should inform the centre if there is any unusual upsurge of flu-like illness.