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Emerging infections: what have we learnt from SARS?
A briefing document prepared for the Royal Society by David Bradley
(sciencebase.com).
On 13th January 2004, the Royal Society held a scientific meeting entitled "Emerging
infections: what have we learnt from SARS?". This briefing document was prepared
subsequently to summarize key issues.
Infectious threats
We are facing more and more emerging infections partly because of international
travel and rising population densities. Severe acute respiratory syndrome (SARS) in
the winter of 2002-2003 was just a single example that has taught the international
medical community, researchers, and policy makers lessons we must learn if we are
to fight new, emergent infectious agents.
Our hunter-gatherer ancestors were not afflicted with the likes of measles, mumps,
and chicken pox. These diseases emerged as people moved more from place to place
and populations rose. Environmental change too means the world has become the
perfect culture medium for new pathogens.
We have, of course, benefited from two decades of disease research stimulated by
HIV but we simply cannot predict the next new pathogen and must improve our
understanding of spreading diseases if we are to face the next threat. Issues of
preparedness, medical ethics, and civil liberties must be addressed urgently before
the successor to SARS emerges.
Footnote to the meeting
Outbreaks of avian H5N1 disease have been reported in a number of countries
including Vietnam, Thailand, Laos, Cambodia, China, and Indonesia. Human cases
have also been reported in Thailand, but the concern is whether human disease has
been missed elsewhere. This poses the most recent threat to human health and is
one with significant implications for animal production and economies. The longterm, global implications are only just being considered.
Session 1:
The myth of a germ-free Nirvana
Thirty years ago various experts pronounced that we had conquered infectious
disease; we could thank better hygiene, sterilized food, vaccines, and antibiotics.
But, in recent years there has been renewed anxiety about infectious diseases, said
epidemiologist Tony McMichael of the Australia National University, Canberra.
We have been confronted with the emergence of legionnaire's disease, lyme disease,
HIV/AIDS, human "mad cow" disease, ebola and hanta viruses, SARS, and many
other new diseases. Old adversaries, such as tuberculosis, dengue fever, cholera,
and malaria have re-emerged. Cholera is a case in point. A bacterium once confined
mainly to South Asia, cholera kills thousands from Asia to Europe and from Africa to
North and Latin America.
Pathogens are spreading more freely. McMichael blamed increased personal mobility,
greater international trade and ever more densely populated cities. Greater poverty,
changes in sexual practices, and intravenous drug use too, coupled with intensive
food production and some modern medical procedures have created many new
openings for evolving microbes.
Environmental changes have affected how humans come into contact with microbes
while social changes, at the individual and community level ensure human networks,
technology choices, politics, and the distribution of disadvantage all create new
opportunities for infection.
McMichael argued that new circumstances lead to unusual contact between people
and pathogens. Millions of years ago our descent from the trees exposed us to the
savannah's disease-bearing insects. The advent of agriculture and civilization
brought us into closer contact with animal diseases than ever before. War and
invasions helped nations swap these diseases, and European expansion spread them
to the New World.
McMichael proposed that we are living through a fourth transition - a global
transition. Demographic, environmental, behavioural, technological, and other
changes in human ecology created an environment well suited for the emergence of
new diseases. Injudicious modern medicine is to blame for drug resistance in
opportunistic microbes. Climate change and changes in river ecosystems are also
influencing infectious disease emergence and spread.
Many factors influence the emergence of infectious diseases so what is the relative
importance of environmental and social factors, asked McMichael. Having failed to
achieve the germ-free Nirvana, we must recognize the increasingly globalised
microbial world that will continue to produce infectious surprises. Rather than use
the militaristic hyperbole of a war on microbes, we must approach the topic within an
ecological framework. This will help us anticipate the effects of environmental and
social change and act accordingly.
Viruses bridge the species gap
The list of emergent viruses continues to grow. In the early 1990s, there was HIV,
ebola, lassa, and others, almost all having jumped from their natural host species to
humans. More recently, hepatitis C, Sin Nombre, West Nile, and of course SARS
emerged. The common factor, said Dr Eddie Holmes of the University of Oxford, is
that they use RNA rather than DNA to carry their genetic code.
Holmes believes that the genetics of our immune systems and viral genetics should
be an equally important research focus. To infect a new species, an emerging virus
has to overcome the new host's immune system and to replicate in its cells, the
success of which depend on both viral and host genetics.
But, Holmes asked, why do such pathogens emerge and what controls the
emergence? Ecological change, as emphasized in Tony McMichael's talk, is the
governing factor - change in human proximity and change in host-species population
density. The key to understanding lies in the fact that RNA viruses mutate a million
times more rapidly than organisms with DNA. This endows them with great
adaptability. On the other hand, a high mutation rate constrains viral evolution by
capping the viral genome's size, which limits adaptability. Higher mutation rates,
after all, mean more chance of error in the viral genes. This "error-threshold",
explained Holmes, means that if a virus has to evolve a lot to jump between species
then it is more likely to fail. We eat a multitude of plant viruses everyday but no one
has yet fallen prey to turnip mosaic virus.
The coronaviruses such as SARS, are different. They have a much bigger genome
than other RNA viruses, which means that SARS and its relatives should evolve more
slowly but their larger genome gives them greater adaptability. A better
understanding of the constraints to RNA virus evolution will allow us to make better
predictions about the emergence of new viruses and help us find improved
therapeutic procedures. Rather than thinking about what RNA viruses can do, we
should concentrate on their limitations.
Is influenza the model that could help us tackle emerging viruses?
Despite intense investigation and the development of vaccine, influenza virus
remains a major threat to public health, said Professor Robin Bush of the University
of California, Irvine. But, do influenza's lessons apply to SARS?
Influenza and SARS are both RNA viruses with many similarities and many major
differences. But, the emergence of new strains of influenza throughout human
history can help us understand SARS.
Killer strains of influenza type A are thought to begin in the intestines of waterfowl,
such as ducks. The intestine harbours the viral components that, under the right
conditions, allow the virus to jump to another species, such as a chicken, and then to
people. The leap from symptom-free ducks to the Spanish influenza epidemic of
1918 remains a mystery. Where exactly did this killer come from and why did it
become so virulent?
Research on genetic material extracted from frozen samples has taken us
tantalizingly close to an answer. We have no genetic records of the strains just prior
to their emergence in people so stepping back to the source is currently impossible.
We must answer why these viruses that have infected only birds for decades
suddenly become infectious to humans? Bush suggested that if we continue to keep
company with our animals and provide them with over-crowded living conditions
then the frequency of emerging epidemics will inevitably increase.
Clues may lie in the places where these viruses appear to originate - the farms and
markets of Southeast Asia, for instance. We must understand the factors involved in
an emerging virus appearing and learn the lessons of diseases such as influenza if
we hope to come quickly to grips with SARS and its ilk.
Session 2:
Confronting a new disease
An unusual type of pneumonia emerged in Guangdong in November 2002, said
Professor Malik Peiris of the Department of Microbiology, Faculty of Medicine,
University of Hong Kong. It caused a significant outbreak in the provincial capital
Guangzhou in January 2003 and left the authorities and hospitals in nearby Hong
Kong with a serious cause for concern. After all, how could any hospital spot a case
of this new atypical pneumonia when around 100 patients each month enter hospital
intensive care wards with severe pneumonia?
Information from clinicians in Guangdong suggested that one unusual feature of the
disease was its propensity to give rise to clusters of cases with pneumonia,
particularly in health care workers. By February and March, outbreaks of pneumonia
were reported from Hanoi and Hong Kong, and medical scientists recognized they
were dealing with an entirely new disease, subsequently called Severe Acute
Respiratory Syndrome, SARS.
The World Health Organization announced that we were facing a major disease
threat and significant numbers of cases were observed in Singapore, Canada and
with individual cases also been reported in Germany. Peiris was among those who
recognized the SARS coronavirus.
The SARS virus was detectable in the respiratory tract, faeces and urine of sufferers
indicating that infection was not confined to the respiratory tract. In contrast with
other respiratory viral infections, SARS CoV was relatively stable in the environment
and in faeces. Respiratory droplets were likely to be a primary source of
transmission, but detection of high concentrations of virus in faeces and its
environmental stability suggested that faecal contamination may be relevant in
explaining large community outbreaks such as that in Amoy Gardens, Hong Kong.
One question that plagued doctors during the outbreak was how to identify patients
with the new disease. SARS remains an enigmatic disease, said Peiris. Symptoms
look very much like pneumonia. The disease differs in many respects from other
respiratory viral infections. Infection seems to be associated with the severe
pneumonic spectrum of the illness and asymptomatic infection seems uncommon. In
contrast to other respiratory viral infections, the viral load of SARS CoV in the upper
respiratory tract and faeces is low in the first few days of illness and peaks around
day 10 of illness. This may explain why transmission is less common early in the
disease.
A virus similar to SARS CoV has been identified in palm civets, a tree-dwelling
mongoose eaten as a delicacy in China, and other small mammals in wild game
animal markets in Guangdong. These popular markets, Peiris explained, may be the
interfaces where species to species transmission occurs. People working in these
markets and handling these animals often show antibodies to the virus in their blood.
SARS was a pandemic whose control required a coordinated global response, said
Peiris. The World Health Organization provided leadership in this regard by
coordinating a series of virtual research networks who shared information on the
causes, diagnosis, disease spread, and clinical management. He pointed out that
SARS is but one emerging virus and that medical science should not focus purely on
this disease. At the time of the meeting, there was already major concern about an
outbreak among people in Vietnam of a strain of bird influenza known as H5N1.
Proof positive
Dutch virologist Professor Albert Osterhaus of Erasmus University, Rotterdam, The
Netherlands, outlined the scientific proof that led to a novel coronavirus being
identified as the primary cause of SARS. The laboratory network for SARS that was
established by the World Health Organization was quite instrumental in allowing
scientists to make this discovery, said Osterhaus.
At first, this unusual pneumonia baffled scientists. The SARS coronavirus had already
been implicated and Osterhaus and his colleagues began performing clinical and
experimental test to determine the virus' precise role in causing SARS.
As part of the network trying to prove whether SARS-CoV was the primary cause,
they had access to clinical and post-mortem specimens from 436 SARS patients from
six countries. They began testing these samples for infection with SARS-CoV and
also for human Metapneumovirus, a well-known childhood infection. Its presence in
so many of the SARS cases seemed to suggest it had a primary role in the disease.
Indeed, both the newly discovered coronavirus and the well-known
metapneumovirus were common factors in SARS.
To prove one way or another which virus was causing SARS, the researchers had to
prove three things. First, they had to show that the suspect is present in all known
cases. Secondly, they have to isolate it from samples and grow it in the laboratory.
And, finally, isolated cultures must be capable of causing the disease in newly
infected individuals. The first two are relatively straightforward, it is the latter that
involves the most difficult step.
The researchers had to infect related species with SARS-CoV in an attempt to
replicate the symptoms of SARS. Infected animals were found to exude SARS-CoV
from the nose, mouth, and pharynx just two days after infection. Two of the four
animals tested also had the same lung damage seen in SARS patients. Those
infected with just the metapneuomovirus did not display SARS symptoms. It became
clear that the coronavirus was the likely primary cause of SARS itself.
Indeed, reported Osterhaus, SARS-CoV infection was diagnosed in about three
quarters of patients who had SARS, while metapneumovirus was ultimately
diagnosed only in about 12% of patients. This Osterhaus said, suggested that SARSCoV was the most likely cause of SARS. Producing the proof was a tour de force,
taking a mere three weeks.
The team demonstrated that three different species other than humans could be
infected with the coronavirus and displayed SARS symptoms. This, Osterhaus,
suggested provides researchers with model systems that will allow them to study the
disease's early stages and to test vaccination and antiviral therapy.
Spotting SARS
The onset of illness in SARS can take anything up to 12 days after a person first
comes into contact with the SARS coronavirus, explained Dr Maria Zambon Head of
the Respiratory Virus Unit of the UK's Health Protection Agency. Symptoms can
persist for many days with most patients recovering but it being fatal in a large
proportion of elderly people.
Robust tests and confirmatory checks are needed. The SARS virus can be detected in
either the illness phase or by detecting footprints of the virus (antibodies) in the
recovery phase, but ensuring the right test works at the right time will assist in an
emergency by providing an accurate estimate of how many people have been
affected or infected.
When SARS first emerged, medical researchers hunted for the virus in lung
secretions. But it was soon found that the test results depended on the timing
sample collection relative to the onset of illness, and that other samples including
stool and blood samples might also be useful. This provides doctors with a dilemma how to tell whether or not a patient suffering symptoms resembling SARS is infected
with that or another virus with similar symptoms.
A robust test, said Zambon, will not only help doctors bring an epidemic under
control, but would allow them to estimate the disease's true burden. Albert
Osterhaus, Malik Peiris and colleagues in proving SARS coronavirus to be the primary
cause of the disease in April 2003 provided the basis for diagnostic tests.
Molecular tests have to be able to work fast, finding the telltale genetic fingerprints
of the virus within 12 hours of sample collection to provide doctors with confirmation
of a case. A rapid test is no simple task and raises quality control issues, such as
ensuring good confirmation strategies and communication so that doctors
understand that they have to cope with a margin of error when a negative result
may be falsely negative.
To ensure the most robust and accurate tests are developed, requires a strong
research infrastructure, Zambon emphasized. What you do in normal conditions
determines what you do in an emergency. If you do not have a strong R&D
capability, there will be no capacity to deal with an emergency, such as having to
develop new tests quickly to meet an unanticipated threat, such as SARS.
Session 3: Understanding transmission and control
A very different disease
The SARS epidemic of 2002-2003 was rather unusual, began Professor Roy Anderson
FRS of the Department of Infectious Disease Epidemiology, at Imperial College
London. For instance, its transmission efficiency was low by comparison with viruses
such as Influenza A, it had a high case fatality rate especially amongst the elderly,
and there was a high incidence of infection among health workers.
In regions badly affected by SARS there was much suffering, many deaths, serious
disruption to social and work activities, and considerable economic losses. The
isolation and quarantining of hundreds of thousands of people became essential to
bring the disease under control as too were the tight restrictions on travel in some
countries. The World Health Organization also played a vital role in co-ordinating the
international response and helping to bring the disease quickly under control. We
were very lucky this time round, he said. Draconian public health measures are
relatively simple to implement in China and other neighbouring regions where this
particular disease originated, but how would the people of North America and
Western Europe cope with such restrictions on their liberties as mass quarantining?
The cause of SARS was narrowed down to a single coronavirus and diagnostic tests
of varying precision have been developed to help us detect it. Epidemiological
research must now be carried out to help us understand how the disease spreads,
especially given what is actually a very low transmissibility of the virus, compared
with influenza. Data capture and information capture systems were put in place
somewhat late during the epidemic. In future outbreaks this area needs to be
improved so that researchers can gather knowledge about the disease's
epidemiology. During the SARS epidemic data capture systems were more effective
in some regions and entirely ineffective in others. An international, centralised
database would also allow doctors to record the effects of different medicines on the
disease and so provide useful information for other doctors an in the longer-term
epidemiologists.
We were extremely lucky with the SARS epidemic, said Anderson. SARS caused a
around 800 or so deaths, influenza type A kills 30000 people in the USA every year.
In the next global epidemic, we may not be so lucky in terms of biology or where the
disease emerges. He suggested that we must keep SARS in perspective but not
become complacent and assume that "we have been successful once, we will be
again".
The emergence of SARS
Professor Nan Shan ZHONG of the Guangzhou Respiratory Disease Research Institute
suggested in his talk that he would probably raise more questions than he would
make conclusions. The first case of SARS in China was recorded on 25th November
2002, and he saw his first definite case in December. The subsequent outbreak of
the disease caught the world's health systems unprepared. The worst Chinese
epidemic was in Beijing with 2500 cases, while Guangdong province, where SARS
first emerged, had some 1500 cases. The result was serious impact on social
stability, particularly in China, and ultimately on the global economy.
From both the clinical epidemiological and virological points of view, SARS originated
in the Guangdong province of China. Data showed that there may have been
interspecies transmission between wild animals and humans, explained ZHONG, and
a national campaign to kill rats as one possible source of infection was instigated by
the government. As ZHONG pointed out, while rats harbour many diseases it is other
animals, in particular the palm civet, which has been demonstrated to be the host of
the emergent virus. The virus was found to be highly concentrated in the civets'
faeces and the first cases in 2002 occurred among animal traders. ZHONG believes it
imperative these animals are culled and their use in cuisine be stopped.
ZHONG suggests that the health authorities must remain alert for the possible
resurgence of SARS during the winter of 2003-2004 and into the spring. Indeed, the
Provincial Department of Health in Guangdong has formulated a pre-warning policy
based on early identification based on antibody lab tests. With early reporting, early
isolation must be enforced to allow the health services to manage a resurgence.
Professionals have now been trained to identify the disease quickly and accurately
and a report network has been established throughout mainland China to ensure a
rapid response to new SARS cases. ZHONG told the meeting that in the previous
three weeks three new cases of SARS had emerged.
Should the disease re-emerge, corticosteroid and non-invasive ventilation should be
reiterated as the treatment of choice for patients with critical SARS. Traditional
Chinese medicine (TCM) may also have use in early adjunctive therapy. An
inactivated SARS vaccine is now in clinical trials and early results suggest it is safe
and efficacious and may be available in an emergency.
Fighting SARS in China
Victory over the first SARS epidemic resulted from the efforts of the medical and
scientific communities and the political commitment of the authorities in China with
strong international support; the causative agent having been identified within two
weeks of the outbreak, said Professor CHEN Zhu, Vice President of the Chinese
Academy of Sciences (CAS). Two weeks later, the SARS genome was unravelled.
Three programmes have now been implemented under the Chinese taskforce research into causes and effects, diagnosis, treatment and prevention, and drug and
vaccine development.
The initial SARS infections, which were seen among restaurant researchers in
particular, were rather weak, and reminiscent of the state of play at the time of the
meeting in the advent of a SARS second coming. It was then the infamous "SuperSpreader" event in Guangzhou Second Hospital, which evoked the epidemics in
Guangzhou, the second phase, and then the Hotel M event that ultimately led to the
massive scale of the SARS epidemic, the third phase to Northern China and other
countries/regions in the world. Comparisons of the genome at each phase together
with information about the relation between human SARS and the disease in the
animal carriers, palm civets, is providing important clues about controlling SARS and
vaccine development.
With regard to diagnosis, treatment, and protection, CHEN added that Guangzhou's
Prof. ZHONG Nan Shan is something of a hero in China for having first identified
SARS as a new pathogen; he and his collaborators developed effective treatments
using corticosteroids, antiviral drugs and non-invasive positive pressure ventilation,
as well as integrating it with Traditional Chinese Medicine.
Diagnostic tools and kits have been developed in response to the first epidemic and
are now revealing themselves to be critical in controlling the recent appearance of
SARS cases in 2004. Physical protective equipment for personal and hospital use are
also being rapidly developed, added CHEN. The Chinese government has issued new
security guidelines to help it cope with another outbreak. The scientific conservation
of samples of the SARS coronavirus for further researchers is another important
measure that CHEN mentioned briefly.
Beijing researchers had reported at the time of the meeting the effectiveness of
inactivated SARS viral particle in laboratory tests, but says CHEN , many questions
remain to be answered before a safe and effective vaccine will be ready.
The lessons of SARS have led to open reporting, especially in China, which means
"next time", the international health and research communities will be better
equipped to respond.
The victims of SARS
Robert Maunder's hospital, the Mount Sinai Hospital in Toronto, was on the frontline
during the SARS epidemic. One aspect of such an epidemic that does not always
immediately come to mind is the psychological impact on health workers.
The outbreak of SARS in 2003 provided a system-wide stress upon healthcare
workers in the Toronto region, said Maunder, reminding us of when public-health
messages were common and quarantine widely used. To understand the
psychological impact on hospital staff and the wider community, we should recall the
eighteenth century when hospitals were considered places to die rather than centres
of healing.
The disease hit Toronto in two waves, said Maunder. The first wave had a major
impact on Mount Sinai Hospital allowing the researchers to survey healthcare
workers at three hospitals in late May. The effect of stringent controls put in place
meant no visitors and non-essential staff ordered to stay home. The public
perception of hospitals was severely affected, hospitals were seen as places with
disease, and healthcare workers were seen as victims and carriers of disease.
Maunder's team has studied data from two sources of information. First,
observations by he and his colleagues of administrators and mental health
professionals providing support during the SARS epidemic in March and April, and a
survey of about 1600 healthcare workers at three Toronto hospitals in May and June.
The results provide a picture of the factors which lead the SARS outbreak to be
experienced as a psychological trauma.
Maunder described how more than 35% of those surveyed reported severe stress
symptoms, including intrusive thoughts and feelings and avoidance and blunted
feelings. The degree of risk of traumatic stress was related to degree and duration of
exposure to SARS patients as well as other factors. These included isolation from
family and colleagues, and the wider community as well as job stress, and problems
with family life. Rules prevented colleagues shaking hands or eating in the hospital
cafeteria compounded the problems leading to poor sleep, anxiety, and
preoccupation with signs of illness among many healthcare workers.
There is a psychological cost to controlling a disease like SARS, said Maunder. This
must be considered when planning the public-health response and invaluable
psychological support provided during the early stages of an outbreak.
New hosts for new diseases
Biologist Dr Diana Bell of the University of East Anglia, Norwich, immediately drew
three conclusions about the nature of emerging diseases like SARS.
First, she suggested that the search for diseases of animal origin should be
extended, not only geographically, but also to small carnivores other than the
masked palm civet from which SARS emerged. Secondly, there are major ecological
shifts favouring the emergence of zoonotic diseases, in South East Asia. Thirdly, new
collaboration between conservation biologists and vertebrate ecologists would help in
finding and controlling such diseases.
The search for disease has focused on the animal markets of Southern China, but
many of the animals traded there are illegally imported. The animal reservoir for
SARS and other viruses could extend far outside China. Moreover, China's
neighbours in the Indochina hotspot of biodiversity - Cambodia, Laos, Thailand - also
exploit wild animals in the restaurant trades, traditional medicine, perfumes, skins
for clothing, and as pets. The limelight has shone on three small carnivore species:
the masked palm civet, Chinese ferret badger, and raccoon dog. Many other
endangered species are also exploited.
Bell suggested that putative hosts must be screened across all routes from capture
to marketplace and beyond. This would allow researchers to pinpoint at what point
the animals first show signs of infection.
Wildlife trade is not restricted to South East Asia. African civets are eaten as bush
meat and should be screened. Moreover, the problem is very much a global one.
Huge numbers of wild animals are imported into the USA each year, including 49
million live amphibians and 2 million live reptiles. The wildlife trade, Bell said, is not
only a threat to biodiversity but seriously threatens human health.
To combat this trade, it is important to hit supply and demand, said Bell. Better law
enforcement and community participation as well as education could be key to
reducing the demand for wild meat.
Session 4: Planning and preparedness
An international disease response
SARS appeared in a world that is plagued by many emerging and re-emerging
diseases that occur on every continent not just the developing world, stated Dr David
Heymann, WHO's Executive Director of Communicable Diseases. The current global
map of outbreaks current is challenging. For instance, at the time of the meeting
there were outbreaks of a high-mortality respiratory syndrome in Afghanistan, acute
diarrhoea in Mozambique/Burundi, H5N1 influenza A, meningitis, measles, acute
respiratory syndrome in China, and cholera in Zambia.
There is great concern, said Heymann, that one day there may be deliberate use of
microbiological agents to cause serious harm. Today, the agents that cause concern
are bacterial, fungal and viral agents, and rickettsial agents that cause typhoid and
fevers.
Our concerns are not new; there have been concern about infectious diseases for
centuries, if not millennia. Efforts during the 19th and 20th centuries to control the
spread of infection culminated in 1969 with the little-known International Health
Regulations, which provide the framework for disease surveillance and response.
They are endorsed by WHO member nations and the aim is to prevent the spread of
disease with minimal interference to world traffic.
Recently, WHO has begun to network with research groups creating everything from
formal collaborative links between laboratories around the world and informal
internet discussion groups. Information is constantly being brought in through these
routes to WHO. Such active information exchange is in stark contrast to the passive
system where in 1969 and where disease reporting was not even compulsory.
Information allows WHO to decide whether a reported disease outbreak is of urgent
international health importance. If it is not, the nation will be asked to contain it. If it
is, then a collaborative risk assessment is undertaken. This amounts, said Heymann,
to a new and active approach to disease.
The SARS epidemic illustrated this new coordinated global response to disease,
relying on the world's best laboratory scientists, clinicians, and epidemiologists to
investigate and provide guidelines for care and containment. An extensive
knowledge-base concerning SARS is now in the public domain, which will provide
vital information for dealing with this and other diseases.
Preparing the UK to fight disease
Activities during the last year or so in the UK mirror the international efforts to deal
with the first major emerging disease of the twenty-first century, SARS, said Dr
David Harper of the Department of Health. Health systems have been severely
tested but unprecedented international collaboration instigated by the WHO has
provided a unique opportunity to control this disease and to begin to understand its
causes and effects.
In the UK, said Harper, there was a very large response even though the UK suffered
only a small number of probable cases. The Department of Health led the UK
response from a policy and political perspective. At the same time the Health
Protection Agency, created in April 2003, was suddenly plunged into an emergency
situation. The success was in large part due to the necessary close working of the
key players in the health protection community.
Harper suggested that there were several issues that emerged from the SARS
outbreak of particular concern to the UK but that provide broader lessons for other
countries. Specifically, we cannot be complacent. Recent cases have highlighted that
SARS has not "gone away" and contingency planning to deal with this and other
diseases must be ready.
He suggested that the framework produced for handling the likes of SARS is dynamic
so that it can quickly be adapted to other diseases. The UK will benefit from the
effort that went into the SARS planning to continue to improve other areas of health
protection. The practicalities of implementing health exit screening, which was not
required in the UK during the SARS outbreak, have been considered. Harper added
that the likely efficacy of this and other control measures are being assessed
internationally. The legal base for public health action is kept under review, informed
by expert medical and scientific advice where necessary.
The experience of SARS in 2003 has effectively informed the UK and provided an
early warning that has reinforced the need for the Department of Health, the Health
Protection Agency and the NHS to ready the framework for an integrated, escalating
response to a future re-emergence of SARS or another disease.
Avoiding ethical hazards
The Baroness Onora O'Neill, Principal of Newnham College, Cambridge considered
whether informed consent procedures provide appropriate standards for public health
measures of the sort that might be needed to address SARS and other emerging
diseases.
Medical ethics over the last quarter century had focussed almost entirely on clinical
ethics, and within that on the importance of informed consent by individual patients
for ethically acceptable health care. Supposedly informed consent should be specific
rather than generic, and processes of consenting should be explicit rather than
implied. Data protection legislation had placed parallel demands on the use of
personal data. Information itself was perceived as a personal possession, to be used
only where specific, explicit consent had been given, or it had been irreversibly
anonymised. Such requirements could undermine public health measures, since data
linkage (which precludes irreversible anonymisation) is needed for epidemiological
studies and secondary data analyses, yet obtaining informed consent is not always
feasible.
Consent cannot provide the basis for all medical ethics, said Baroness O'Neill. It was
well-known that informed consent cannot be given by patients whose competence is
variable, erratic, or missing, or by children. Even where competent consent is given
to some intervention, it does not transfer either to the logical implications or to the
expected consequences of that intervention. For example, a patient may consent to
the removal of unspecified tissue, yet deny consenting to the removal of an organ.
Their consent might be thought to cover the removal of organs, which consist of
tissue; but this inference was fallacious.
Population studies of the sort required to gain knowledge of diseases such as SARS
could not proceed if individual consent for the use of samples and information were
required of each patient. More generally, public goods, such as protection from
infection, cannot be tailored to individual choice. Baroness O'Neill concluded with a
quotation from Cicero: "Salus populi suprema lex", "The safety of the people is the
highest law".