Replies to LegCo questions
LCQ20: Prevent and control influenza outbreaks
Following is a question by the Hon Frederick Fung and a written reply by the
Secretary for Food and Health, Dr York Chow, in the Legislative Council today
(December 14):
Question:
It has been reported that the health authorities in the United States earlier
expressed concern about a new H3N2 influenza (flu) virus mutated from H1N1 human
swine flu virus, pointing that this flu variant, which combines the genes from
the viruses of ordinary human flu, H5N1 avian flu and H1N1 human swine flu, can
be transmitted among humans, and there is a possibility of a major outbreak. In
this connection, will the Government inform this Council:
(a) whether the authorities have approached the overseas health authorities
concerned and the World Health Organisation to seek the latest information about
the aforesaid new flu virus; if they have, of the details (including the
characteristics of the aforesaid new flu virus, mode of transmission and
spreading rate, symptoms as compared with those of ordinary flu, possible
complications, methods of treatment, as well as comparison with the human swine
flu epidemic which broke out and spread in Mexico in 2009, etc.); and
(b) of the mechanism currently in place for comprehensively monitoring the
possible appearance of any new flu variant; whether the authorities have any
measure (e.g. any plan to specify the aforesaid new flu as a statutory
notifiable disease, etc.) in place at present to cope with the possible major
outbreak of the aforesaid new flu; and whether they have formulated any
contingency plan for the purposes of perfecting the mechanism for the prevention
and control of flu, disseminating information, flexibly deploying and purchasing
medical resources, organising and coordinating the work of various government
departments in combating epidemics, strengthening public health education and
immunisation, etc.; if they have, of the details?
Reply:
President,
Following the establishment of the Centre for Health Protection (CHP) in 2004,
the Government has established a comprehensive surveillance system that monitors
influenza activity in the community. The system includes laboratory surveillance
and sentinel surveillance networks which cover childcare centres, kindergartens,
residential care homes for the elderly, Hospital Authority out-patient clinics,
clinics of private practitioners and Chinese medicine practitioners. Moreover,
the authorities have been working closely with local universities to gather
expertise and experience from various specialties in order to formulate
strategies and measures for the prevention and control of influenza.
In monitoring the latest global situation of influenza, the Government has also
been collaborating closely with health authorities such as the World Health
Organisation (WHO), the Ministry of Health of China and the Centers for Disease
Control and Prevention (CDC) of the United States (US). In the regional context,
the Government has established a direct communication mechanism with the
relevant authorities of Guangdong Province and Macao. This ensures that the
three places can expeditiously and effectively exchange important information
about influenza outbreaks, and contingency measures can be taken to reduce the
chance of outbreaks.
As far as seasonal influenza is concerned, it should be noted that serious
influenza infections can occur even in healthy individuals, and that influenza
vaccines are safe and effective. Therefore, the authorities encourage all
members of the public to consult their family doctors to receive seasonal
influenza vaccination for personal protection. On the other hand, the Scientific
Committee on Vaccine Preventable Diseases under CHP will take into account a
variety of scientific factors, including the local disease burden and
international experience, before recommending priority target groups for
seasonal influenza vaccination. Priority target groups recommended for seasonal
influenza vaccination in the 2011/12 season include children aged between 6
months and less than 6 years, persons aged 50 years or above, pregnant women,
pig farmers and pig-slaughtering industry personnel etc.
My reply to the two parts of the question is as follows:
(a) The Government has been closely monitoring developments concerning a
swine-origin triple reassortant influenza A (H3N2) (S-OtrH3N2) virus in the US.
CHP has written to WHO and CDC in order to understand and follow up on the
latest developments concerning the virus in the US.
According to information provided by WHO and CDC, there have been 11 recorded
cases of the reassortant virus in the US since July this year. All infected
patients have recovered and the majority of cases involved relatively mild
illness. Seven of the cases (including two in Indiana, three in Pennsylvania and
two in Maine) involved direct or indirect exposure to swine. Epidemiological
investigations conducted by the US authorities so far revealed that the four
latest cases recently reported had no direct exposure to swine before the onset
of symptoms - among the cases, three cases reported in Iowa involved children
studying in the same childcare facility and investigation is underway to
ascertain whether other children in the same childcare facility and their family
members had exposure to swine; one other case was reported in West Virginia and
further investigation of contacts and potential sources of infection are
ongoing. According to the epidemiological investigations on these four cases,
limited human-to-human transmission may have occurred but there is no evidence
of sustained human-to-human transmission of the virus. According to advice of
the CDC, the virus is susceptible to oseltamivir (Tamiflu) and zanamivir (Relenza).
As the virus is different to the influenza A (H3N2) virus common to humans, the
existing seasonal influenza vaccine can only provide limited cross-protection
against the virus to adults and cannot provide protection to children.
Generally speaking, swine influenza, including the aforementioned swine
influenza A (swine flu), is a respiratory disease of pigs caused by type A
influenza virus. Swine flu viruses commonly cause influenza outbreaks among
pigs, and do not normally infect humans. There have been sporadic human
infections with swine flu and the majority of such cases involved direct
exposure to swine. Symptoms are similar to those of human seasonal influenza.
Influenza A (H1N1) 2009, which broke out in Mexico and spread in 2009, was an
exceptional case. There was sustained human-to-human transmission and spread
rapidly across the globe. This is different to the swine-origin triple
reassortant influenza A (H3N2) (S-OtrH3N2) mentioned in the question.
The Government will continue to closely monitor the situation and update the
public on any new developments concerning the virus. A relevant press release
was issued on November 29, 2011.
(b) The Government has been closely monitoring influenza activity in the local
community and has established a comprehensive disease surveillance system
through collaboration with the Hospital Authority and private hospitals, general
practitioners and institutions on sentinel surveillance; investigation of
institutional outbreaks; hospital admissions data monitoring and media
monitoring. Results of influenza surveillance are uploaded weekly on the CHP
website for public information.
In addition, the Government has a sensitive laboratory surveillance system for
influenza virus. The Public Health Laboratory Services Branch under CHP conducts
characterisation of all influenza viruses detected, including antigenic and
genetic analysis.
In 1999, the Department of Health recorded a case of a child infected with a
swine-origin influenza A (H3N2) virus. The child recovered and was discharged
after two days of hospitalisation. To date, no human infections with this
swine-origin triple reassortant influenza A (H3N2) (S-OtrH3N2) virus in the US
have been detected in Hong Kong.
The Centre for Food Safety has also been assisting the University of Hong Kong
in conducting research and surveillance on influenza activity in pigs at the
slaughterhouse. Recent surveillance results revealed that a swine influenza H3N2
virus that had picked up genes of the influenza A (H1N1) 2009 virus, detected at
the Sheung Shui Slaughterhouse, was different from the swine-origin triple
reassortant influenza A (H3N2) (S-OtrH3N2) virus in the US.
Under the Prevention and Control of Disease Ordinance (Cap. 599), at present
type A influenza viruses (H2, H5, H7 and H9) are notifiable infectious diseases.
The Government will continue to closely monitor the development of influenza
globally and locally, and strengthen its liaison with WHO, Mainland and overseas
health authorities. We will also pay particular attention to whether there is a
genetic mutation of the virus and whether viral virulence and transmissibility
have increased. If necessary, we will make amendments to the legislation to
include other viruses as statutorily notifiable diseases.
In addition, the Government has adopted a multi-pronged approach to prevent and
control influenza outbreaks. We have formulated the Framework of Government's
Preparedness Plan for Influenza Pandemic, which set outs in detail the command
structure, preparation and control measures for influenza pandemic in Hong Kong.
The Plan includes a number of preventive and control measures in case of novel
influenza and influenza pandemic, such as stepping up surveillance and rapid
diagnosis, maintaining medical services, promoting basic protection measures
like personal and environmental hygiene, risk communication etc.
To ensure that relevant Government departments are well prepared for major
infectious disease outbreaks, CHP regularly conducts exercises and drills on the
preparedness plan, so as to test our preparedness and responsiveness for
infectious disease outbreaks in Hong Kong. The Government will also continue to
maintain a stockpile of some 20 million doses of antivirals to meet the needs in
case of an influenza pandemic.
Ends/Wednesday, December 14, 2011
Issued at HKT 12:30
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