Latest update of surveillance data in winter influenza season
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     The Centre for Health Protection (CHP) of the Department of Health today (February 18) 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. In the upcoming Lunar New Year, 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 or attending festive gatherings. High-risk persons may wear masks against infections," a spokesman for the CHP said.

     "Surveillance so far shows that severe and fatal influenza-associated cases in adults affected the elderly most. While vaccination remains an important means to prevent influenza with a certain degree of cross-protection against different but related strains, it also reduces disease severity, particularly for high-risk persons," the spokesman added.

Local surveillance
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     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 34.6 per cent in the first week of February to 27.4 per cent last week, compared with the peak at 38.7 per cent in the last week of January. About 95 per cent of influenza virus detections were A(H3N2).

     Regarding severe cases, from noon yesterday (February 17) to noon today, 10 additional cases of influenza-associated admission to intensive care units or death (including eight 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 332 (237 deaths) so far. Among them, 320 were A(H3N2), seven were B and five were A pending subtype. In the last winter season in early 2014, 266 (133 deaths) were filed.

     Of note, in the 332 cases and 237 deaths above, 284 cases (85.5 per cent) and 225 deaths (94.9 per cent) involved elderly persons aged 65 or above. Senior citizens yet to be vaccinated should do so promptly as vaccination can reduce disease severity, hospitalisations and deaths, particularly for high-risk groups.

     "Last week, 74 cases (56 deaths) with a daily average of 10.6 cases (eight deaths) were recorded, a record high in influenza seasons since 2011, compared with 63 cases (44 deaths) with a daily average of nine cases (6.3 deaths) in the previous week," the spokesman said.

     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 14 (no deaths) and all were A(H3N2). In 2014, 27 cases (four deaths) were filed.

     Turning to influenza-like illness (ILI), the number of institutional outbreaks reported to the CHP further decreased from 43 (affecting 208 persons) in the first week of February to 37 (145 persons) last week. As of yesterday, 13 (79 persons) had been recorded this week. The outbreaks in the past four weeks mainly occurred in residential care homes for the elderly and primary schools (34.1 per cent each).

     In addition, the average ILI consultation rate reported by both sentinel general out-patient clinics (GOPCs) and private doctors remained high. In GOPCs, it dropped from 11.5 ILI cases per 1 000 consultations in the first week of February to 7.9 last week, while that among private doctors also dropped from 71.0 to 68.6 in the same period.

     The influenza-associated public hospital admission rate among children aged under 5 and the elderly aged 65 or above was respectively 2.50 and 3.07 cases per 10 000 persons last week, compared with 3.08 and 3.76 respectively in the preceding one. The rate for the elderly has remained at a high level, which is above the levels recorded in the past few years.

Situation of neighbouring and overseas areas
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     The influenza activity in a number of neighbouring and overseas areas in the northern hemisphere has peaked and started to decrease, with the A(H3N2) virus predominating so far.

     The peak of the influenza season may have passed in North America. The percentage that tested positive for influenza viruses in the United States further dropped to 14.9 per cent in the first week of February from the peak at 31.79 per cent in the last week of 2014. That in Canada further decreased to 21.6 per cent from the peak at 34.6 per cent in the same period.

     That in England further dropped to 11.3 per cent in the first week of February from the peak at 31.7 per cent in the first week of 2015. In Japan, the average number of reported ILI cases per sentinel site further decreased to 19.03 in the first week of February from the peak at 39.42 in that ending January 25.

     The percentage that tested positive for influenza viruses in Taiwan decreased to 17.2 per cent in the week ending January 31 from 24.1 per cent in the preceding one.

     That in Europe remained at a high level of 51 per cent in the first week of February, over the threshold of 10 per cent.

     Locally, as of February 15, about 246 000 and 239 000 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:

* Receive seasonal influenza vaccination for personal protection;
* Wash hands with liquid soap and water properly whenever possibly contaminated;
* When hands are not visibly soiled, clean them with 70 to 80 per cent alcohol-based handrub;
* Wash or clean hands frequently, especially before touching the mouth, nose or eyes, or after touching public installations such as handrails or door knobs;
* Cover the nose and mouth when sneezing or coughing, and wash hands thoroughly afterwards;
* Dispose of soiled tissue paper properly in a lidded rubbish bin;
* Put on a surgical mask when respiratory symptoms develop;
* Maintain good indoor ventilation;
* When influenza is prevalent, avoid going to crowded or poorly ventilated public places; high-risk individuals may consider putting on surgical masks when staying in such places; and
* Maintain a balanced diet, exercise regularly, take adequate rest, do not smoke and avoid overstress.

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

* The influenza page (www.chp.gov.hk/en/view_content/14843.html);
* The weekly Flu Express report (www.chp.gov.hk/en/view_content/2108.html);
* The update on severe seasonal influenza cases (www.chp.gov.hk/files/pdf/flu_update_en.pdf);
* The vaccination schemes page (www.chp.gov.hk/en/view_content/17980.html);
* The list of participating doctors (www.chp.gov.hk/en/view_content/34664.html);
* The Facebook Page (fb.com/CentreforHealthProtection); and
* The YouTube Channel (youtube.com/c/ChpGovHkChannel).

Ends/Wednesday, February 18, 2015
Issued at HKT 18:12

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