J R Soc Med 2003;96:374-378
doi:10.1258/jrsm.96.8.374
© 2003 Royal Society of Medicine
The SARS epidemic in Hong Kong: what lessons have we learned?
Lee Shiu Hung MD FFCM
Chinese University of Hong Kong, Hong Kong, China
Correspondence to: Emeritus Professor Lee Shiu Hung, Centre for Health
Education and Health Promotion, Flat 2D, Union Court, 18 Fu Kin Street, Tai
Wai, Shatin, New Territories, Hong Kong, China E-mail:
shlee{at}cuhk.edu.hk
 |
INTRODUCTION
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Severe acute respiratory syndrome (SARS) reached Hong Kong in
March
2003.
1 From 11 March
up to 6 June, a total of 1750 cases
had been identified
(
Figure 1), and during the same
period 286
people died of the disease. Before the advent of SARS in Hong
Kong,
the nearby Guangdong Province in Mainland China had experienced
an intense
outbreak of the atypical pneumonia later termed SARS.
This outbreak started in
November 2002 and reached its peak
in February 2003; up to 5 June 2003,
Guangdong had recorded
1511 cases and 57 deaths. Later in April 2003, SARS
cases were
reported in other provinces and cities of Mainland China including
Beijing,
Shanxi, Neimonggol, Tianjin and Hebei. Up to 5 June 2003, Mainland
China
had a total of 5329 cases with 336 reported
deaths.
2
From March onwards, SARS was detected in other countries and areas in the
Asia-Pacific region. By the beginning of June, Singapore had had 205 cases
with 28 deaths, Vietnam 63 cases with 5 deaths and Taiwan 686 cases with 81
deaths.
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METHODS
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The content of this paper was gathered from personal observations
when
attending conferences, seminars and video meetings on SARS,
from academic
staff in the University of Hong Kong, the Chinese
University of Hong Kong and
the medical school in Guangdong,
from clinicians in the Hospital Authority,
and from public health
professionals in the Department of Health who were
either directly
involved in the laboratory investigation, diagnosis and
management
of SARS patients or engaged in efforts to control the disease.
Other
sources were press reports, personal interviews and websites
on SARS
provided by the health and hospital authorities, the
US Centers for Disease
Control and Prevention, the World Health
Organization (WHO) and the Centre for
Disease Control in Mainland
China.
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EPIDEMIOLOGY
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The SARS epidemic in Hong Kong has gone through three phases.
The first was
an explosive outbreak in a teaching hospital,
affecting a large number of
hospital staff and medical students.
This phase took place in March 2003. The
second phase was an
outbreak in the community as a result of the spread of
infection
from the hospital to the
community.
3 This
reached its peak in
early April 2003 when the disease affected a housing
estate
known as Amoy Gardens; a total of 329 residents in that estate
came
down with the disease and 33 died. The third phase began
in early May, with
continuing occurrence of the disease in eight
hospitals and more than 170
housing estates throughout the city
but with the daily number of new cases
declining from double
to single digits in mid-June (the time of writing).
The first phase started when a professor from Guangzhou, who had been
treating patients with atypical pneumonia in a Guangzhou hospital in Mainland
China, visited Hong Kong in February 2003. He stayed at the Metropole Hotel in
Kowloon on 21 February. The professor was already unwell when he travelled to
Hong Kong and on 22 February he was admitted to the Kwong Wah Hospital in
Kowloon. Later he died. From this first index case, 7 other people whose rooms
had been on the same floor of the hotel contracted SARS, including 3 visitors
from Singapore, 1 visitor from Vietnam, 2 visitors from Canada and 1 local
person. Seemingly it was these 7 individuals who, having acquired the
infection from the index case, transmitted SARS to Canada, Vietnam, Singapore,
and elsewhere in Hong Kong. The local person was admitted to a teaching
hospital, the Prince of Wales Hospital, at Shatin on 4 March 2003. From this
patient the disease spread through that hospital, ultimately affecting over
100 medical and nursing personnel.
Amoy Gardens
Phase 2 began in early April with the spread of SARS into the community.
This was the time when daily new cases reached their peak. The severe outbreak
in Amoy Gardens, a housing estate in Kowloon, began at this time. The index
patient in this outbreak was a 33-year-old man who lived in Shenzhen and
visited his brother in Amoy Gardens regularly. His chronic renal disease was
being treated at the Prince of Wales Hospital. SARS symptoms developed on 14
March 2003. On that day and 19 March he visited his brother who owned a flat
in Block E of the estate. He had diarrhoea and used the toilet there. His
brother, his sister-in-law and 2 nurses who attended to him at Prince of Wales
Hospital subsequently developed SARS. By 15 April 2003, there had been 321
SARS cases in Amoy Gardens, with an obvious concentration in Block E
(41%).
A thorough local investigation, conducted by the Department of Health in
collaboration with eight other government agencies, then indicated that
environmental factors had played an important part in this outbreak. Each
block at Amoy Gardens has 8 vertical soil stacks collecting effluent from the
equivalent section on all floors. The soil stack is connected to the water
closets, the basins, the bathtubs and the bathroom floor drains. Each of these
sanitary fixtures is fitted with a U-shaped water trap to prevent foul smells
and insects getting into the toilets from the soil stack. Clearly, for this to
work, the U-traps must contain water. However, because most households were in
the habit of cleaning the bathroom floor by mopping rather than flushing with
water, the U-traps connected to most floor drains were probably dry and not
functioning properly (Figure
2).
Laboratory studies indicate that many patients with SARS excrete
coronavirus in their
stools.5 As many as
two-thirds of the patients in the Amoy Gardens outbreak had diarrhoea, so a
very substantial virus load would have been discharged into the sewerage in
Block E. Probably the index patient infected only a small group of Block E
residents, with the remainder acquiring the disease via sewage,
person-to-person contact and shared communal facilities such as lifts and
staircases. These residents subsequently transmitted the disease to others
both within and outside Block E through person-to-person contact and
environmental contamination.
The bathroom floor drains with dried-up U-traps provided a pathway through
which residents came into contact with small droplets containing viruses from
the contaminated sewage. These droplets entered the bathroom floor drain
through negative pressure generated by exhaust fans when the bathroom was
being used with the door closed. Water vapour generated during a shower, and
the moist conditions of the bathroom, could also have facilitated the
formation of water droplets. The likelihood of exposure was enhanced by the
small dimensions of the bathroom units (about 3.5 square metres).
Virus-contaminated droplets could readily have been deposited on floor mats,
towels, toiletries and other bathroom equipment.
The possibility of disease transmission by other routes—airborne,
water-borne, infected dust aerosols—has been examined but there is
neither epidemiological nor laboratory support for such mechanisms. A team of
environmental experts from the WHO, visiting Amoy Gardens by invitation,
agreed with the results of the investigation and also declared the buildings,
now cleansed and disinfected, safe for
habitation.6
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PREVENTION AND CONTROL
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The prevention and control measures undertaken in Hong Kong
include: (1)
preventive education and publicity; (2) tracing
the source of infection; (3)
introducing five major control
measures (compulsory isolation and surveillance
of contacts,
stopping school and university education sessions, exchange
of
epidemiological information between Hong Kong and Mainland
China, temperature
checking of travellers at points of entry
and exit, district-wide cleansing
campaigns); (4) strengthening
collaboration and communication with Mainland
China and the
WHO; and (5) developing a quick diagnostic test for SARS.
When the first few cases of SARS were identified, the Department of Health
of the Hong Kong Special Administrative Region Government passed legislation
to make SARS a notifiable infectious disease. Patients with SARS were isolated
in the hospitals, and family or close contacts were kept under surveillance,
initially at home but later in isolation centres where they were observed for
10 days.
The public health workers undertook the investigations of the source of
infection and the tracing of contacts, and promoted application of control
measures including the wearing of masks, strict adherence to personal hygiene,
and disinfection and cleansing of affected households and housing estates.
Incoming and outgoing travellers were screened for fever exceeding 38°C
and were required to complete a health declaration form. Apart from their
intrinsic value, these measures served to alert the public to the high
infectivity of SARS and the need for preventive measures.
In the middle of May 2003, when the epidemic began to slow down, the
Government announced further measures. Three committees headed by senior
government officials were established—one responsible for the overall
cleansing campaigns and environmental improvements in the housing estates; a
second for drawing up programmes to revitalize the economy of the city,
including tourism, trade and employment; and the third to devise ways to
promote community involvement and partnership in improving the physical,
social and economic environments of the city. Additional funds were approved
to support research on diagnosis, treatment, and vaccine development for SARS.
A Centre for Disease Control and Prevention would be developed to strengthen
surveillance, research, training and collaboration with other health
authorities regionally and internationally.
At the end of May, the Hong Kong Government of the Special Administrative
Region appointed a committee of nine experts from the USA, the UK, Australia,
Mainland China and Hong Kong to make recommendations on future prevention and
control of the disease. I am a member of this team.
Canada
It is pertinent to refer briefly to the SARS outbreak in Canada, the
country most severely affected outside
Asia.7 As mentioned
earlier, 2 visitors from Canada were infected at the Metropole Hotel, in
Kowloon. Returning to Toronto they developed symptoms and later gave rise to a
cluster of 16 other cases including 4 family members, 2 close contacts and 10
healthcare workers. When the outbreak in Toronto began in March 2003, the WHO
issued a warning notice to travellers intending to visit the city—a
notice later withdrawn after representations from the Canadian Health
Ministry. When no further cases were reported, the outbreak seemed to have
been brought under control. However, in mid-May there were further cases. In
view of the evidence that more than one generation of cases had occurred, the
WHO restored Toronto to the list of infected areas. By 14 June over 90
probable cases had been reported in this resurgence. This Canadian experience
highlights the importance of continuing vigilance even when cases begin to
decline.
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SHORTCOMINGS
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The SARS outbreak reached epidemic proportions so quickly and
explosively
that the health and hospital authorities were unprepared.
Initially there was
an acute shortage of masks and protective
clothing for the medical and health
personnel, who were hard
hit by the disease. Lack of epidemiological
information about
the disease hampered the prompt application of effective
control
measures. Because of inadequate communication, panic developed
in the
community and weakened cooperation and support from the
public. Some contacts
did not respond when the Department of
Health asked them to attend for
surveillance and quarantine.
There were difficulties in designating hospitals
for the isolation
and treatment of SARS patients, because Hong Kong has no
infectious-disease
hospital as such. Since the wards of the general hospitals
were
not designed for patients with infectious disease, infection
of
healthcare staff became a serious issue. By June 2003, 386
medical, nursing
and other healthcare workers in the hospitals
and clinics had developed SARS
and 8 of them (4 doctors, 1 nurse
and 3 healthcare assistants) had died. Some
hospital wards had
to be closed temporarily, and general patients were
transferred
to other medical institutions to make way for the SARS patients.
In
the absence of a specific isolation centre for infectious disease,
contacts
were accommodated in holiday and recreation centres
outside the city. Not
being designed for the purpose, these
were far from ideal. There was much
evidence of distress among
front-line healthcare workers and members of the
public, many
of whom were anxious, fearful and depressed. The SARS epidemic
damaged
not only health but also tourism, international travel and trade,
social
and business activity, and educational programmes.
Several features of the epidemic rendered control measures difficult in
Hong Kong. Initially the cause was unknown, and lack of information on the
mode of transmission hampered efforts at control. Because of the large number
of cases, patients were admitted into various general hospitals unequipped to
handle highly infectious diseases and numerous medical and nursing staff
became infected. The lack of isolation facilities allowed infection of
patients admitted to the same wards for other reasons. Many patients when
admitted to hospital did not have the typical signs of SARS (fever, cough,
evidence of chest infection), thus worsening the difficulties of
cross-infection control. At one point there was discussion whether a single
specially equipped hospital with 600-1000 beds should be designated to cater
solely for patients with SARS or with fever on admission. Another issue was
whether there should be permanent and proper quarantine facilities for
isolation of contacts. Surveillance of contacts at home was not considered
effective.
A further controversy arose over the International Health Regulations
(IHR). These specify three diseases—namely, cholera, plague and yellow
fever—about which the WHO must be notified by the health authorities
concerned. The city must then declare itself ‘infected’ with that
disease until after twice the incubation period from the last case reported.
At the beginning of the SARS epidemic there was doubt whether Hong Kong should
declare itself infected with SARS. Although the existing IHR did not include
SARS, the WHO had issued a warning notice advising travellers not to visit
Hong Kong because of the SARS epidemic—an advisory that drastically
reduced the number of international visitors. In May 2003, when the epidemic
began to show signs of decline, the WHO set out three conditions for
withdrawal of the advisory—no case of SARS spreading to other cities
outside Hong Kong; number of new cases less than 5 daily for three days; and
number of patients in the hospitals less than 60. At the end of May, the WHO
deemed these conditions fulfilled and lifted its advisory on international
travellers, though Hong Kong remained on the list of infected
areas.5
In some circles the WHO is perceived to have over-reacted to the
epidemic,8 causing
unnecessary panic on the international scene and putting unjustified barriers
in the way of persons from ‘infected’ areas wishing to attend such
events as business exhibitions or international sports activities. It is
noteworthy that, in May 2003, the World Health Assembly passed a resolution to
revise the IHR. This was an appropriate decision since the emergence of new
and highly infectious diseases has made the existing regulations out of
date.
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LESSONS LEARNED
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The lessons learned by Hong Kong can be summarized as follows:
- SARS differed from previous epidemic infectious diseases in its explosive
spread, which caught the health and hospital authorities by surprise and
ill-prepared.
- Inadequate epidemiological information about the disease hampered the
prompt application of effective control measures. Insufficient communication
with the public led to panic and thus weakened public cooperation and
support.
- Because there were no specified infectious disease hospitals, there were
difficulties in designating hospitals for the isolation and treatment of SARS
patients.
- The SARS epidemic in Hong Kong not only affected the health of the people
but also had social, economic, and humanitarian repercussions. It unveiled
deficiencies in the public health arena and in coordination between the
Department of Health and the Hospital Authority—reflected in lack of
action between 22 February, when the index patient was admitted to Kwong Wah
Hospital, and 4 March when the local contact arrived at the Prince of Wales
Hospital. In that interval, the alarm could have been raised and front-line
staff could have prepared themselves.
- There was also deficient communication between the Secretary (Ministry)
level responsible for health policy and the management level responsible for
operation of the hospitals. Management inertia at various levels hampered
decision-making and delayed implementation of effective measures.
- The SARS epidemic also shed light on basic failings of the existing
healthcare system in Hong Kong—overcrowded wards; poor ventilation in
some hospitals; lack of isolation facilities; inadequate intensive care
facilities; staff already working under heavy pressure; difficulty in
isolating and cohorting patients with suspected or possible SARS, particularly
at the point of admission and immediately thereafter.
- The effect of the outbreak on intensive care and nursing personnel was
disproportionately high. This worsened the pressures on other branches,
particularly during the recovery phase when normal services had to be
resumed.
- Healthcare workers were put at special risk by certain procedures including
use of nebulizers, endotracheal suction and intubation, cardiopulmonary
resuscitation, nasogastric feeding, and the use of high flow rates of
oxygen.9 The high
risk presented by these procedures has implications for medical practice and
organization of hospital care in the future.
- There is a need to strengthen the exchange of epidemiological information
on infectious diseases, especially the emergence of new infections, between
the health authorities in Mainland China and Hong Kong. The establishment of a
Centre for Disease Control and Prevention in Hong Kong should meet this
need.
Hong Kong will continue to face the challenges of infectious disease,
because of increasing environmental pollution, population movements, the
influx of refugees and immigrants, the emergence of new infections and the
changing lifestyle and behaviour of the
population.10 There
is a great need to set up a Centre for Disease Control and Prevention in Hong
Kong so as to strengthen surveillance and exchange of epidemiological
information with other health authorities, to undertake research and
development on new vaccines and to train medical and scientific personnel on
prevention, treatment and control of infectious diseases. On the plus side,
the epidemic created an unprecedented sense of unity among all
sectors—Government, non-governmental organizations, medical and nursing
personnel—in the struggle to contain the epidemic. Various foundations
were set up by non-governmental organizations and by public-spirited citizens
to provide financial support to victims of SARS and their families. The
devotion and self-sacrifice of medical and healthcare staff drew praise and
appreciation from all sides, and strengthened the city's resolve to cope
better with the challenges of infectious diseases in future. In this way, Hong
Kong can be said to have turned the threats of the SARS epidemic into
opportunities.
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REFERENCES
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- Department of Health, Hong Kong. Severe Acute Respiratory
Syndrome (SARS) Statistics, March-May 2003.
[http://www.info.gov.hk/dh/]
- Severe Acute Respiratory Syndrome (SARS) Statistics, Mainland
China, up to 17 May 2003
[http://www.chinacdc.net.cn/default.asp]
- Donnelly CA, Ghani AC, Leung GM, et al. Epidemiological
determinants of spread of causal agent of severe acute respiratory syndrome in
Hong Kong. Lancet 2003;
361: 1761-6[CrossRef][Medline]
- Department of Health, Hong Kong. Outbreak of Severe
Acute Respiratory Syndrome (SARS) at Amoy Gardens, Kowloon Bay, Hong Kong.
Main Findings of the Investigation, 17 April 2003. Hong Kong:
DoH, 2003
- Peiris M, Lai ST, Poon LM, et al. Coronavirus as a
possible cause of severe acute respiratory syndrome.
Lancet 2003;
361:1319
-25[CrossRef][Medline]
- WHO Regional Office for the Western Pacific. WHO Environmental
Health Team Reports on Amoy Gardens
[http://www.who.int/en/]
- WHO Update 78—Situation in Toronto, 11 June 2003
[http://www.who.int/csr/don/2003_06_11a/en]
- SARS: a WHO-induced panic? Far Eastern Econ
Rev 22 May 2003
- Tomlinson B, Cockram C. SARS: experience at Prince of Wales
Hospital, Hong Kong. Lancet 2003;
361: 1486-7[CrossRef][Medline]
- Lee SH. Prevention and Control of Communicable Diseases
in Hong Kong. Hong Kong: Government Printer,1994
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INTRODUCTION
METHODS
