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The Centre for Health Protection (CHP) of the Department of Health today (April 9) 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 latest surveillance data show that overall influenza activity further decreased close to the baseline level. We will continue to closely monitor whether it will remain at a low level in the coming week," a spokesman for the CHP said.
Laboratory surveillance
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Among respiratory specimens received by the CHP's Public Health Laboratory Services Branch, the percentage positive for seasonal influenza viruses further decreased to 9.6 per cent in the first week of April from 14.5 per cent in the preceding week.
The proportion of A(H3N2) among influenza virus detections dropped from 76.7 per cent to 66.9 per cent in the last two weeks, while that of B correspondingly increased from 20.2 per cent to 29.7 per cent. That of A(H1) and C remained low.
Severe cases
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From noon yesterday (April 8) to noon today, 21 additional cases of influenza-associated admissions to intensive care units or death, including 18 deaths, among adults aged 18 or above had been recorded under the enhanced surveillance in collaboration with public and private hospitals reactivated since January 2, bringing the total to 612 (469 deaths) so far. Among them, 574 were A(H3N2), eight were A(H1N1)pdm09, seven were A pending subtype and 23 were B. In the last winter season in early 2014, 266 cases (133 deaths) were filed.
"The 21 additional cases were recorded under the enhanced surveillance and identified through retrospective case review into unclassified cases by the Hospital Authority, among which three were admitted to public hospitals in April with the remaining 13 in March, two in February and three in January. They do not reflect the latest influenza activity or disease severity," the spokesman explained.
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. The total this year thus remains at 18 (one death) and all were A(H3N2). In 2014, 27 cases (four deaths) were filed.
Institutional outbreaks
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Turning to influenza-like illness (ILI), two institutional outbreaks affecting 11 persons were reported to the CHP yesterday (April 8) by residential care homes for the elderly (RCHEs), the outbreaks so far this week.
The weekly number of outbreaks decreased from 11 affecting 74 persons in the fourth week of March to four (affecting 16 persons) last week. Outbreaks in the past four weeks mainly occurred in RCHEs (57 per cent) and schools (38 per cent).
Vaccination
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As of April 5, about 258 000 doses and 248 000 doses of influenza vaccines had been administered to eligible groups under the Government Vaccination Programme and the Vaccination Subsidy Schemes 2014/15 respectively, an increase of eight per cent and five per cent from the same period of last year.
Neighbouring and overseas areas
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While influenza activity in a number of overseas areas in the northern hemisphere had peaked and continued to decrease and influenza activity in other areas in the northern hemisphere remained elevated, the B virus has been increasing by proportion.
In Taiwan, the influenza season persisted. The percentage positive for influenza viruses stood at a high level of 32.9 per cent in the third week of March and the B virus detections have been on the rise.
In Europe, the proportion of influenza virus detections in sentinel specimens stood at 37 per cent in the week ending March 30, which is still over the threshold of 10 per cent, and B accounted for about 70 per cent of virus detections.
In Japan, the average number of reported ILI cases per sentinel site has been decreasing. The percentage positive for influenza viruses in the United States, Canada and England has also been decreasing close to the baseline, and B accounted for the majority of recent virus detections.
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 (www.fb.com/CentreforHealthProtection); and
* The YouTube Channel (www.youtube.com/c/ChpGovHkChannel).
Ends/Thursday, April 9, 2015
Issued at HKT 18:23
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