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Tuesday, 25 March 2003, 10h00
Palais des
Nations
World Health Organization
Dr David Heymann, Executive Director, Communicable
Diseases
Dr Klaus Stohr, Scientist, CSR
Dr Julie Hall,
Medical Officer, CSR
Mr Dick Thompson, Communications
Officer
Dr David Heymann: Thank you again for coming to this
press briefing. We are now 10 days into an outbreak of what we
believe is a previously unrecognized disease in humans. We have
cases that have spread out of Hong Kong and Viet Nam, throughout the
world, and we have a laboratory group which has identified two
different viruses in patient specimens. A paramyxo virus and a
corona virus. At the same time, we’ve done epidemiological studies
which, to date, and that means to this very minute, have shown us
that most if not all cases can be identified in a chain of
transmission from the patient back somehow to a family member or to
a contact directly with a hospital worker or with a hotel in Hong
Kong.
So studies on the side of epidemiology are also going
well and as of now we still maintain that travel is not to be
interrupted throughout the world at this point in time. But as you
know there’s much, much information coming out of Hong Kong and
there’s been a rapid increase in the number of cases this week and
we are in regular contact with Hong Kong and with our Regional
Office in Manila and we will be reconsidering today our travel
recommendations as we do every day.
Today we will be with a group of industrialized
countries that have cases as well as the countries in which the
majority of cases are occurring in Asia. So we’re at the end of a
10-day period which has seen a remarkable working together of
scientists, epidemiologists and countries in the world to better
understand and stop the spread of what we believe is a previously
unrecognized infectious agent. Thank you.
Dr Klaus Stohr: Eight days ago, WHO established a
network of 11 laboratories in 9 countries. We invited these
laboratories to participate in this collaborative effort to help
identify the causative agent of this disease and to develop rapidly
a diagnostic test. Now 8 days later, these 11 laboratories in these
9 countries have found already two very strong contenders, two
viruses which are consistently isolated from many patients from very
many different countries.
The research is ongoing. It is not normal that one
disease is caused by two viruses. We will have to strengthen the
activities, particularly as far as electron microscopy is concerned,
as well as genetic analysis. These data did not become available
without an unprecedented, an unprecedented level of collaboration
between all these network members in all the 11 laboratories in 9
countries.
Dr Julie Hall: As has been previously mentioned, this
has been an unprecedented collaboration between various
organizations and WHO. WHO is working very closely with all its
partners in the Global Outbreak Alert and Response Network. We’ve
been able to produce guidance based on clinical and epidemiological
evidence. That guidance is posted on our web site on the SARS page
for all to see. We’ve established a logistic basis throughout the
world and worked in close collaboration with bi-lateral arrangements
from a variety of different countries to ensure that supplies are in
place. As Klaus has mentioned, there’s been an international
collaborative effort in terms of research in laboratories and at the
back there are various sheets which you may or may not have already
picked up which identify the organizations that are working within
the laboratory collaboration. We also have three field teams in
place.
In Hanoi there are 9 people who have been there since
the 14th of March. Their key focus has been on infection control and
where infection control has been put in place and has been practised
effectively, we have seen a dramatic reduction in inter-hospital and
community transfer of this agent. They have also been working hard
in terms of clinical management and we now have a large data set of
information about this syndrome which will help us to understand its
clinical cause and possible effective treatments for it. It’s been
shown that good supportive care has been effective and we are now in
a position in Viet Nam where, now that we have developed a discharge
policy, a number of patients are likely to be discharged from
hospital in the very near future.
In Hong Kong we have a five-person team that has been
focusing on epidemiological research and has provided a lot of data
in terms of how this infectious agent has been transferred and
transmitted between people and what infection control measures are
required. A five-person team arrived on Sunday in China. They have a
remit to review the epidemiological data that’s been collected by
the Chinese authorities and also to help support the microbiology
and virology investigations into this outbreak. So there has been an
unprecedented collaborative effort and all the institutions that are
working in the various forms, whether it be in the field teams, in
the clinical network or in the laboratory network; the details of
all of those are on the sheets at the back if people want to look at
those.
Q. When I look at the latest figures from the WHO, it
is really worrying because it seems to me that only in Hong Kong,
the figures kept increasing and we have now 10 deaths. What are the
factors that make Hong Kong so special? It seems the situation is
not under control.
A. Dr David Heymann: Our teams are also concerned
about the situation in Hong Kong because of its spread in many
different hospitals and our team there is working with the
government in Hong Kong, not only to better understand what’s going
on in Hong Kong as far as the epidemiology or the transmission of
the disease, but also in trying to stop the spread of the disease.
There are people who are infection control experts working in the
government and with the government to try to make sure that we can
stop this outbreak. I just need to remind you though that at present
there is no evidence that there is any transmission other than close
contact with patients, either sitting next to patients or being in
close contact with patients. But this adds to the urgency in Hong
Kong to make sure that this remains true in the studies that are
found because now, as you know, there are cases in schools, there
are cases other places and we need to make sure that if there are
other cases in schools, they aren’t cases that are randomly
occurring but are cases which sat next to students who were sick.
And the same goes for airplanes, if there are airplanes that
transmitted someone who’s sick, we would want to be sure that it was
people sitting next to that person and not the ventilation system in
the aeroplane which was spreading the disease. We have no evidence
of the latter right now but this is why studies are so important and
why we reinforced our team to work with the very excellent teams in
Hong Kong to find out what’s going on for sure.
Q. A couple of questions. I assume you are supportive
of the mass quarantine that Singapore authorities have announced
that they are starting today. Singapore today began ordering
hundreds of people to stay at home and it’s being described as the
world’s largest quarantine. They are making use of the Infectious
Diseases Act which is the first time they’ve ever used it. So (a)
are you in favour of measures like that? and (b) my second question
is, when you were talking about the travel advisory, you seemed to
stress there’s no new advice for the present. But are you expecting
this might change after the meeting with industrialized countries
today?
A. Dr David Heymann: The first is that WHO puts out
recommendations on travel but it’s countries who make the final
decision based on their legislation and their national laws. That’s
why we’re meeting with countries today because other countries have
the same concerns as Singapore does. And we’re trying to work with
them to better understand the basis for their concerns. The
recommendations of WHO are always evidence-based. That means that
when we get evidence that suggests that we should be changing a
policy, we move to change that policy. We’ve been meeting on a
regular basis by telephone with many countries. Today we will bring
all those countries together to discuss travel recommendations. And
I will say what I would say every day, that we leave it open that if
there is new evidence with which we can make a better policy or a
different policy, we will do that and we will not hesitate to do it.
So, our recommendations will be evidence-based and we do not make a
recommendation if there’s no evidence to support that. This many
times occurs in national contexts because there are rules or laws
which require them to judge on the side of safety rather than on the
side of non-safety, if you understand what I’m saying. So, yes
there’s always a chance that WHO will change its recommendations and
we will keep you posted if that should occur. Thank you.
Q. With Singapore, I presume that you are in favour of
measures taken, such as those in Singapore – mass quarantine?
A. Dr David Heymann: Governments take a decision based
on the conditions locally. If for some reason Singapore feels that
they will not be able to trace all cases because there’s such great
mobility in their populations that they must make restrictions on
them, then that’s what they’ve decided to do. Our recommendation is
that there be no restrictions at present. But that’s a global
recommendation. And again, that’s being reconsidered on a daily
basis and will be re-considered today at 2.30 pm in our conference
call.
Q. The question about the two viruses having been, or
two families of viruses having been associated with this disease or
with this outbreak. You said it was not normal. if I’m not mistaken.
Could you give us an idea of whether or not it’s possible for a
single disease to be caused by two viruses or does it mean, or is it
more likely that at least one of the samples might not be related to
SARS?
A. Dr Klaus Stohr: Speaking as a scientist, we are
looking at a very interesting and a fascinating situation. Looking
from the point of infectious disease control, we are a bit puzzled
because we are not only dealing apparently with one pathogen but
with two. The reason why we believe that both pathogens should be
given equal attention is that there is consistent finding of both
pathogens in individual patients or of either of the pathogens in
other patients. What we are seeing actually are three hypotheses.
The first hypothesis is that one of the viruses, for instance the
corona virus, causes the disease, and that might be a new corona
virus. The second hypothesis is that the paramyxo viruses cause the
disease and if that was the case, it’s certainly also a new paramyxo
virus. The third hypothesis is, very obvious, is that these two
pathogens have to come together to cause this very severe outbreak.
One of the viruses, for instance the corona virus, is known to live
in immune cells, cells which are important for the defence, for the
body defence against infection. So what one could hypothesize is
that this corona virus destroys or at least diminishes the immunity
in the patient so that the second virus has practically an open door
to go in and to sicken the patient beyond what this virus would be
able to do normally.
Dr David Heymann: Let me just add to that: so, you
know, the hypotheses, there could be a fourth. It is possible that
both are common viruses: one found in all the patients, even though
it's not causing disease, and the other will be the disease causing
agent, so they could both be found but not be related in any way,
just there by chance. So it's a very complicated issue that's being
sorted out.
Q. In China, is the team in Beijing getting new
figures on how many cases we have in China? Also, can they go to
Guangdong or will they just remain in Beijing doing that kind of
laboratory service?
A. Dr David Heymann: Yesterday the team in China had a
question from the Government, and that was "why is WHO not putting
on its web site the 305 cases that we reported?" The answer was
because we only started recording cases from 1 February, and we
don't know how many cases China had from 1 February on. That made
the Chinese believe that they needed to go back and look at their
data, and they've promised us they would do that and give us more
information. Today that information has not come out yet. Our team
has met with officials from Guangdong and from Beijing but the
information is not yet available, but we have reason to believe that
it will be made available and that there is very much interest in
Beijing by the internatinoal press on these issues as well as by the
press from outside Beijing.
Q. Is the team going to Guangdong?
A.Dr David Heymann: The team has not yet been invited
to go to Guangdong and we don't know whether that invitation will be
coming. Certainly our wish would be that the Government will permit
us to work with them in all aspects of this outbreak.
Q. Do you think it's advisable for the team to go to
Guangdong to help investigate what's going on? Did WHO request
specifically that they should go to Guangdong?
A. Dr David Heymann: WHO has requested the Government
to let the team work with them as best it possibly can, and we would
hope that that would include working in Guangdong as well as working
in Beijing.
Q. I have two questions. My first is that there is a
lot of hypothesising about the first case of the outbreak, a lot of
media reported that it was the Chinese businessman who came back
from China who went to Hanoi who was the one who was dead in Hong
Kong. Do you have any information about the first case? Secondly,
can you clarify the route of transmission. Is it possible to have
transmission by air?
A. Dr Julie Hall: We have quite a lot of information
about the gentleman, what we are calling the "Hanoi index case", the
Chinese American businessman who went to Hanoi, became unwell and
was then transferred to hospital in Hong Kong. He was transferred in
isolation and treated in isolation as well once he got to Hong Kong.
The team in Hanoi are currently following up his travels prior to
arriving in Hanoi. It seems that he travelled quite extensively
prior to becoming unwell and prior to arrival in Viet Nam. Further
details on that are currently being sought by our team so that we
can follow his travels in the 2-3 weeks prior to him becoming unwell
in a little more detail. Obviously, when somebody becomes unwell in
one country, lives in another country, and is then transferred for
care in a third country, it does take a while for all this detailed
information to be put together.
Dr David Heymann: To date, in looking at every case
that occurs, it has not been possible to say that there was not
close contact with another patient, be it a family member of a
hospital worker, a hospital worker, or one of the initial cases. Now
that information comes in on a daily basis. If, and the minute we
find, that there are cases which cannot be traced to close contact
with another patient or another person at risk, we will then be very
concerned that this might have become airborne. Airborne meaning
that you would be at risk sitting where you are. The way it is today
that we believe from the evidence we have, the only person at risk
in this room would be Dr Stohr, who's sitting next to me. But if we
find that you are at risk, we will immediately have to consider a
whole series of new measures to recommend and the studies will have
to intensify to find out how it's circulating wider than just by
person to person contact.
Q. From what I understand from the end of last week,
you were becoming more confident that you had this under control.
But the data this week seems to show the opposite. How confident are
you that you've got it under control? How concerned are you that it
could be getting worse instead of better?
A. Dr David Heymann: When we made the global alert 10
days ago, our goal was to stop outbreaks occurring in other
countries than Hong Kong and Viet Nam because of imported cases. We
knew that Canada had had imported cases and had had local
transmission within Canada. If you look at the global alert, it has
brought in reports of disease from many different countries - 13 I
believe is the latest count - and there has been no additional
outbreaks set up in those countries. So the global containment
exercise has been successful to date. The exercise of containing the
disease in Viet Nam appears to have been successful, there has been
a slowdown in new cases, hospital infection control has been
strengthened in hospitals, and it appears that that outbreak has
been contained in Viet Nam. In Singapore, where there were imported
cases, there appears to now have been a closing in on contacts of
patients, and we believe that the situation in Singapore is being
controlled. In Hong Kong there is a very difficult situation and a
different situation in that 10 hospitals are now involved. It is a
very important exercise to contain the disease in these 10
hospitals. We also know that people have been in schools who have
become sick, so there is where the efforts must be now intensified
in addition to better understanding what is going on in China. So we
have two countries in which we are very concerned now - Hong Kong -
and in finding out more about what is going on in China because
those are the two countries where we have less information and we
are less sure that containment activities are being successful.
Q. For the incubation period of the disease, WHO said
that it was 2-5 days or 2-7 days. In Hong Kong, however, the doctor
was in close contact with the patient 11 or 12 days before. So
people are now concerned whether we should play safe and extend the
incubation period so that the virus won't spread even further. Do
you have any information and recommendation on this?
A. Dr Klaus Stohr: Thank you. The incubation period is
the period between the infection, when the patient gets in contact
possibly with the pathogen, and when the first clinical signs occur.
Now that is a very important period of time because it tells us
presumably that during this period of time the person can start
spreading the virus. The incubation period in Hanoi, from the data
which has been collected during the first two weeks of the outbreak,
the average incubation period is 4.5 days. The minimum incubation
period is 2 days. The maximum incubation period is 7 days. Very
similar data were forthcoming from Singapore, with a minimum 2 days,
maximum 7 days. We are talking about a biological phenomenon and we
cannot rule out that there have been slightly shorter or slightly
longer incubation periods. However, we have also to realize that not
every contact of a doctor with a patient must necessarily lead to an
infection so even if there has already been contact between the
doctor and the patient over a period of time perhaps the infection
took only place 4 or 5 days after the contact began and the doctor
started incubating. We are looking at a new disease. We are looking
at possibly two different viruses so we really have to cautious in
drawing generic and absolute conclusions. The data that we have are
relatively firm 2 days to 7 days and we have to take more data and
analyse it, and these data are going to be collected particularly
from Hong Kong and particularly in Hanoi, but there will be
analytical information perhaps like you describe but that has to be
verified.
Q. Now we have 10 days of the global alert, can we say
what of the number of cases known, what the mortality percentage
is?
A. Dr Julie Hall: It has remained pretty static over
the last 10 days, it's around about 4% of mortality rate. So it's
quite low and we haven't seen any change in that mortality rate over
the 10 days.
Q. In that case is it really such a horrible scurge
that's menacing the world, because normally influenza has that kind
of mortality rate doesn't it?
A. Dr David Heymann: I would differ I would say that
this is not a low mortality rate, we want zero mortality rate. This
is a 4% mortality in a disease for which we do not yet know the
cause. So it's a very serious issue in having a 4% morality of a
disease for which we don't yet know the cause and which is spreading
throughout the world. 4% is a level of mortality that could be
equivalent to other viral infections in many parts of the world.
It's equivalent of what might be occurring with West Nile, it's
probably more than what is happening with West Nile in North
America. Dr Klaus Stohr: The low mortality rate is perhaps also
being contributed to the enormous clinical efforts taken with those
patients. In one hospital in Hong Kong there are more than 150
patients, almost 30 of whom are in intensive care. Quite a few of
them are on ventilators, they would die without mechanical
ventilation. The health system is burdened almost to the limit in
quite a few of the hospitals and we have of course to look at the
case mortality rate and morbidity but also at the burden on the
public health system which is enormous. Dr David Heymann: And just
to put one more thing in perspective. Suppose that there were two
diseases occurring at the same time, SARS and a disease which causes
the same symptoms but is less severe. It my be that this second less
severe background disease, caused by another virus, would case a
different case fatality rate. We can only begin to distinguish
genuine SARS cases from other less severe diseases having similar
initial symptoms when we have a diagnostic test. So we're still far
from understanding everything.
Q. A technical question - if you do decide to change
your travel advisory, will you let us know by email?
A. Mr Dick Thompson: On the web rather than email. A
transcript of this press conference will be on the web this
afternoon. Thank you.
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