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Press Release

Latest update of surveillance data in winter influenza season

25 February 2015

The Centre for Health Protection (CHP) of the Department of Health today (February 25) reported the latest surveillance data of the winter influenza season, and again urged the public to heighten vigilance and get vaccinated early against seasonal influenza.

"The overall influenza activity in Hong Kong remains at a very high level and is expected to remain at a high level for some time. We also noted that the influenza activity of Macau and Taiwan is on the rise," a spokesman for the CHP said.

"The public should maintain strict personal hygiene both locally and during travel. Wash or clean hands frequently, especially before touching the mouth, nose or eyes, or after touching public installations such as handrails or door knobs. Wear a mask when respiratory symptoms develop, especially when going to crowded places. High-risk persons may wear masks against infections," the spokesman added.

Local surveillance

As for laboratory surveillance, among respiratory specimens received by the CHP's Public Health Laboratory Services Branch, the percentage that tested positive for seasonal influenza viruses decreased from 27.5 per cent in the second week of February to 25.1 per cent last week, compared with the peak at 38.7 per cent in the last week of January. About 93 per cent of influenza virus detections were A(H3N2).

Regarding severe cases, from noon yesterday (February 24) to noon today, 14 additional cases of influenza-associated admission to intensive care units or death (including 10 deaths) among adults aged 18 or above have been recorded under the enhanced surveillance in collaboration with public and private hospitals reactivated since January 2 and an additional death was recorded among previously reported cases, bringing the total to 383 (283 deaths) so far. Among them, 367 were A(H3N2), one was A(H1N1)pdm09, seven were A pending subtype and eight were B. In the last winter season in early 2014, 266 (133 deaths) were filed.

Last week, 56 cases (42 deaths) with a daily average of eight cases (six deaths) were recorded, compared with 74 cases (56 deaths) with a daily average of 10.6 cases (eight deaths) in the previous week.

Meanwhile, no additional cases of severe paediatric influenza-associated complication or death among children aged under 18 have been reported since yesterday via the ongoing reporting system and the total this year hence remains at 17 (one death) and 16 were A(H3N2) while one was A pending subtype. In 2014, 27 cases (four deaths) were filed.

Turning to influenza-like illness (ILI), the number of institutional outbreaks reported to the CHP decreased from 37 (affecting 146 persons) in the second week of February to 19 (102 persons) last week. As of yesterday, 17 (79 persons) had been recorded this week. The outbreaks in the past four weeks mainly occurred in residential care homes for the elderly (39.6 per cent) and primary schools (28.1 per cent).

Situation of neighbouring and overseas areas

The influenza activity of neighbouring areas remained elevated while that of a number of overseas areas in the northern hemisphere has peaked and has been decreasing, with the A(H3N2) virus predominating so far.

In Macau, the percentage that tested positive for H3N2 among ILI patients significantly increased from 6.1 per cent in January to 16.3 per cent to date. In Taiwan, the percentage that tested positive for influenza viruses markedly increased from 17.2 per cent in the last week of January to 41.3 per cent in the first week of February. That in Europe remained at a high level of 49 per cent in the week ending February 15, which is over the threshold of 10 per cent.

In Japan, the average number of reported ILI cases per sentinel site has been decreasing. The percentage that tested positive for influenza viruses in both the United States and Canada has also been decreasing.

Locally, as of February 22, about 248 000 and 240 000 doses of seasonal influenza vaccines have been administered to eligible groups under the Government Vaccination Programme and the Vaccination Subsidy Schemes 2014/15 respectively.

The public should maintain good personal and environmental hygiene against influenza and other respiratory illnesses:

The public may visit the CHP's pages below for more information:



Last Revision Date : 25 Feb 2015