Influenza has killed nine people and seriously sickened 25 adults and children during the winter flu peak while the number of infections is rising steadily.
The Centre for Health Protection said this on Monday as it disclosed a fourfold increase in the number of people being infected in a week.
Urging vigilance, centre director Dr Leung Ting-hung said H1N1 swine flu was the dominating virus strain circulating in the city, while the influenza A sub-type H3N2 had displayed a rising trend.
Last week, the centre received a report of 490 flu infections, four times the 130 cases a week at the end of December.
“The weekly influenza-like illness consultation rates among both general out-patient clinics and private doctors have steadily increased in the past few weeks,” Leung said.
“The public is reminded to remain vigilant in prevention of seasonal influenza, especially the elderly, children and those who suffer from long-term illness.”
He urged vaccination as the virus could case serious complications especially among vulnerable groups.
The number of flu outbreaks in institutions and schools also increased to seven last week from two in the previous week.
Since this year, 23 adults and 2 children were in serious condition and had required intensive care in public hospital – nine of them had died.
H1N1 was responsible for almost half per cent of all cases overall.
But Leung said H3N2, which accounted for just under 30 per cent of all infections, was responsible for most cases last week.
“The viruses characterised to date have been similar to the current local vaccine viruses [in use] this season,” Leung said.
More people are getting flu jabs this year, according to data from the Centre.
As of January 12, some 421,000 doses of seasonal influenza vaccines have been administered to target groups under the Vaccination Subsidy Scheme and the Government Vaccination Programme – 38,000 more than at the same time last year.