Wednesday, September 21, 2016

Hong Kong: An Early Arrival Of Flu

HK CHP Flu Express
HK CHP Flu Express


Hong Kong, somewhat famously, often sees two distinct flu seasons every year, as described in the 2008 PLoS One research paper:

Seasonality of Influenza A(H3N2) Virus: A Hong Kong Perspective (1997–2006)

Julian W. Tang,1,* Karry L. K. Ngai,1 Wai Y. Lam,1 and Paul K. S. Chan1,2

Hong Kong is a subtropical region of almost 7 million people, 95% of whom are ethnic Chinese, with a mean temperature of 24°C and mean relative humidity of 79% [27]. It lies geographically in the Northern hemisphere, and its influenza season occurs during February–April, sometimes with a second peak during June–August, each year.
(Continue . . .)

We can see this unusual pattern depicted in the chart at the top of this post Most years, by the end of September, Hong Kong's flu activity is either negligible or is rapidly trailing off from the summer peak.

In fact, Hong Kong doesn't even begin its winter flu vaccine immunization drive until mid-October.

Influenza is unpredictable, however, and over the past 7 days Hong Kong's CHP has reported several clusters of influenza or flu-like illness.  The latest, at Castle Peaks Hospital, has been identified as Influenza H3.

 All of which has prompted the CHP to make the following announcement today.

The Centre for Health Protection (CHP) of the Department of Health today (September 21) reported that local seasonal influenza activity is increasing and urged the public, particularly young children, the elderly and chronic disease patients, to observe strict hand, personal and environmental hygiene.

 "Since the end of an extended winter influenza season in May 2016, influenza activity has remained low. Yet, the latest surveillance data show that it has started to rise since late August and may increase further in the following weeks," a spokesman for the CHP said.

The percentage positive for seasonal influenza viruses increased from 7.60 per cent in the week ending August 27 to 14.36 per cent last week among respiratory specimens received by the CHP's Public Health Laboratory Services Branch. Most detections were influenza A(H3N2).
Institutional outbreaks of influenza-like illness (ILI) rose markedly when classes resumed in early September. The number of outbreaks increased from six (affecting 27 persons) in the week ending September 10 to 15 (affecting 109 persons) last week. In the past four weeks, outbreaks mainly occurred in elderly homes (35 per cent) and primary schools (23 per cent).

 The influenza-associated admission rate in public hospitals among children aged under 5 increased from 0.57 cases per 10 000 in the week ending August 27 to 1.17 last week, while that among the elderly aged 65 or above rose from 0.43 to 0.89.

For adults aged 18 or above, from September 23 onwards, the CHP will reactivate enhanced surveillance with hospitals for severe seasonal influenza, i.e. influenza-associated admission to Intensive Care Unit or death, to better monitor the severity of illness. A total of 403 cases (including 205 deaths) were recorded in the last winter season from late January to mid-May.

In children under 18, routine surveillance of severe influenza-associated complications or deaths is ongoing. A total of 29 cases (three deaths) had been detected so far this year, including 27 in the last winter season.

 "We will issue letters to doctors, hospitals, institutions and schools to appeal for heightened vigilance," the spokesman said.

"If students or staff develop fever or respiratory symptoms, schools should strongly advise them not to return to campus and to promptly seek medical advice. Management of schools should observe precautions on campus to prevent possible transmission," the spokesman added.

  Institutions and schools are reminded to follow the Guidelines on Prevention of Communicable Diseases on preventive and control measures as well as management of outbreaks, which should be reported to the CHP for prompt follow-up.
Seasonal influenza vaccination programmes in 2016/17 will be launched in mid-October.

 The public should maintain good personal and environmental hygiene for protection 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;
  • 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 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 for more information: the influenza page and the weekly Flu Express report.
Ends/Wednesday, September 21, 2016

Here in the United States we've already started seeing Scattered Early Reports of Seasonal Flu, particularly in some of the southern states.

While we got very lucky last year, and saw a mild, late arriving, and short-lived flu season, there are no guarantees we'll get that lucky again this year.  In fact, the odds are against it. 

Early reports suggest H3N2 may be the dominant flu strain circulating this winter. H3 viruses tend to be more severe than H1 seasons, particularly for the elderly and very young.

As I wrote earlier this week in #NatlPrep: Giving Preparedness A Shot In The Arm,I elected to get my flu shot late last week.

While the vaccine can’t promise 100% protection, it – along with practicing good flu hygiene (washing hands, covering coughs, & staying home if sick) – remains your best strategy for avoiding the flu and staying healthy this winter. 


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