Press Release

CHP appeals for influenza vaccination before travel in Christmas in view of increasing influenza activity overseas

5 December 2014

The Centre for Health Protection (CHP) of the Department of Health today (December 5) appealed to the public to stay vigilant against seasonal influenza and get vaccinated early before travel during the upcoming Christmas period, as recent surveillance data published by health authorities of various travel destinations that are popular among Hong Kong people showed continual increases in their influenza activity.

In Japan, the rate of influenza-like illness (ILI) reported in sentinel sites has been increasing since the week ending October 19, and it rose to 1.90 last week, exceeding the level of 1.00 which indicates the start of the influenza season. The weekly number of positive influenza virus detections in public health institutes increased from a range of nine to 13 detections from October 20 to November 9 to the range of 23 to 33 from November 10 to 30. Over 90 per cent of positive influenza virus detections are influenza A(H3N2).

The United States also recorded an increase in influenza activity in recent weeks. The percentage of specimens tested positive for influenza viruses in laboratory surveillance increased from 3.3 per cent in the week ending October 4 to 12.6 per cent in that ending November 22. Out-patient surveillance revealed that 2.0 per cent of patient visits were due to ILI in the week ending November 22, compared with 1.6 per cent in the preceding week. The US also noted that over 90 per cent of positive influenza virus detections were influenza A with H3N2 being the major subtype.

In Canada, the overall influenza activity has increased since the week ending November 22. In that same week, 16 outbreaks of influenza A were reported in long-term care facilities, rising from two to three outbreaks per week in the two weeks before. The percentage positive for influenza viruses has increased from 2 per cent in the week ending November 1 to 8.6 per cent in that ending November 22. To date, 97 per cent of influenza detections have been influenza A with H3N2 as the most common subtype. Both laboratory and hospitalisation data showed that the majority of cases are the elderly aged over 65.

"As overseas influenza activity is increasing, travellers to these areas should get vaccinated early as the protective immune response takes about two to four weeks to develop. Pregnant women, the elderly, young children and persons with underlying illnesses are strongly advised to get vaccinated promptly as influenza can cause serious complications in high-risk groups. Given that influenza vaccine is safe and effective, and that serious influenza infections can occur even in healthy individuals, seasonal influenza vaccination is recommended for all persons aged 6 months or above, except those with known contraindications," a spokesman for the CHP said.

"Locally, the CHP has all along been closely monitoring overseas and local influenza activity. While the latest local surveillance data show that the overall influenza activity is still low so far, it is expected that the winter influenza season will arrive in the coming one to two months based on the observed seasonality of influenza in the past. In view of recent local cold weather, we urge members of the public to maintain personal and environmental hygiene at all times to prevent seasonal influenza," the spokesman added.

The CHP will continue its routine surveillance of severe paediatric influenza-associated complications or deaths among paediatric patients aged above 1 month and below 18 years. As of December 4, 27 cases (including four deaths) were reported this year, while 13 cases (no deaths) and 17 cases (two deaths) were filed in 2013 and 2012 respectively.

As of November 30, about 132 000 and 166 000 doses of seasonal influenza vaccines have been administered to target groups respectively under the Government Vaccination Programme and the Vaccination Subsidy Scheme 2014/15.

"We call on the health-care sector and the community at large for joint efforts to improve the local influenza vaccination coverage. Members of the public should consult their family doctors on vaccination for personal protection," the spokesman said.

Members of the public are reminded to take heed of the following preventive measures against influenza and other respiratory illnesses:

• Build up good body immunity by having a proper diet, regular exercise and adequate rest, reducing stress and avoiding smoking;
• Maintain good personal and environmental hygiene;
• Wash hands after sneezing, coughing or cleaning the nose;
• Maintain good ventilation;
• Avoid visiting crowded places with poor ventilation; and
• Wear surgical masks and seek medical advice promptly if symptoms of respiratory tract infections or fever develop.

The public may visit the CHP's influenza page (This link will open in a new windowwww.chp.gov.hk/en/view_content/14843.html) for more information on influenza and its prevention.