Examination of Witness (Questions 240
- 259)
WEDNESDAY 7 NOVEMBER 2001
PROFESSOR ROY
ANDERSON
David Taylor
240. Professor Anderson, it will be a surprise
to many, your comment that contiguous culling saved animal lives,
which seems, to me, unproven and possibly even a little provocative.
Did you hear the Chairman refer, earlier on, in the session with
Professor King, to yesterday's Hansard, 146W, which showed over
7,500 mainly Dangerous Contacts, and a few Slaughter on Suspicion
cases were referred to, had laboratory tests of which just five
yielded positive results? Were you able to input into your model,
as the outbreak continued, the fact that so many of these, virtually
all, contiguous cases, in fact, had no clinical sign of the disease
at that stage; and would you expect, with this admitted hindsight,
that there will be further refined models which might indeed move
away from mass contiguous culling as the best reaction?
(Professor Anderson) Yes; two important questions.
Can I deal with the second one last, because it is a much more
difficult one to deal with. You heard Professor King and Dr Grenfell
and Professor Woolhouse comment about the 17 per cent and 50 per
cent figures; and, to me, that says it all. It says that most
of the transmission is local, by whatever route, and the route
is uncertain. If you have not acted on that local transmission
you then get spread to a further contiguous ring. And then most
of Britain, with the high-density livestock regions at the front,
would have been susceptible to the spread of this virus. And,
as I think I said, very publicly, on a `Newsnight' programme,
in the early stages of this epidemic, given the density of livestock
holdings in the UK, a complete disaster was possible at that time,
and it required speedy and draconian action to prevent that happening.
Now, moving to the future, the future is more complicated. The
medical vaccine development areas tend to be a little bit more
advanced than some of the veterinary fields, because commercially
there is more money in it for the pharmaceutical companies, or
vaccine-producing companies; the production of veterinary vaccines
is a bit of a non-profitable area. And, one of the real difficulties
with foot and mouth, all of us would like to see, where there
is a good vaccine, every animal, at birth, immunised. Then, given
that the vaccine has a reasonable duration of efficacy, you would
like to see that repeated with each new birth cohort each year,
and then the consumer would bear the cost, the cost of that vaccine,
and that is the rational and logical way to go. But the questions
here, and my own department did a review of the vaccine data for
the foot and mouth, because there was a lot of confusion at the
early stages about, how long would the vaccine provide protection,
what efficacy would it give in different species, did it work
properly with this strain of virus, and the harsh answer is, (a)
it takes X days to create the protection, so you have got a further
time delay of three to five days, minimum, in some cases you might
have a delay of seven days, before immunising that contiguous
ring actually gives you protection. Then the question, how many
doses of vaccine have you got available; if you dealt with Cumbria
alone, you are talking about tens of millions of doses, almost,
to create herd immunity—it was not available. The vaccine
is stored as a concentrated antigen which then needs a lengthy
process of preparation into dilutions and vaccine doses, and that
was not available; there was an emergency vaccine available within
the European Union, but I think about 1.5 million doses, but do
not take that as gospel, the number needs to be checked. So in
the early stages it was not a practical option. But in the future,
clearly, a great deal of scientific attention should be paid to
this problem, and also one needs to think of production, which
commercial company might be induced to produce such a vaccine,
given that on any vaccine there is a very low profit margin; but
the European Union has got to address that question broadly.
Mr Martlew
241. I am a little worried, the way the debate
has gone today, because we have been mixing foot and mouth with
BSE, and can I congratulate you on answering a very good question
that nobody asked, about the numbers of possible BSE cattle in
the future. But the reality is, of course, they are very different,
our concern over BSE is because it can be transmitted to humans;
there is no concern whatsoever, is there, Professor, that foot
and mouth can be transferred to humans, so it is totally separate?
(Professor Anderson) Yes; correct.
242. And, therefore, it is an animal welfare
disease, so in many cases people would say we were tackling an
economic disease for the agricultural industry. So what you are
saying is that the contiguous cull saved lives; that was only
if we carried on a policy of becoming foot and mouth free, in
actual fact, was it not?
(Professor Anderson) Yes.
243. And that is a policy that really has not
been examined. Did you look at the options of not carrying out
a cull, losing our export trade and treating the animal welfare
problems that it would have created?
(Professor Anderson) It is an important question,
but we did not, for a very good reason, it is not within our expertise.
The role of the different scientific groups was to provide as
good a scienctific analysis as was possible on the timescale,
putting the economics, the cost/benefit, in. If you had done a
cost/benefit analysis of vaccine versus contiguous cull prior
to this year, and you had the interval 1967 to 2001, my guess
is, although I do not know the precise answer, that the cost/benefit
analysis might have fallen against vaccination, in other words,
deal with very infrequent disasters, costly as they are, they
are infrequent. I think the game and the environment have changed
significantly now, post this epidemic, and therefore it needs
good agricultural economists, or good economists, to come in to
look at the cost of various options, in light of our experiences
during this epidemic.
244. So we are actually responding to the way
we dealt with it before, are we not, that we must get rid of this
disease from the UK?
(Professor Anderson) Europe.
245. And the way to do that, we are all focused
totally on which was the best way to do that, and you think the
approach that we have taken was the best way, but nobody actually
looked at the wider picture of `what if we decide not to do this,
it is an animal welfare problem, with regard to sheep it has very
little effect on sheep, we will lose our exports, but that is
an option'; but you are telling me that you did not look at that
option, and, as far as you are aware, nobody else looked at that
option?
(Professor Anderson) It is a question in the review
of what happened, and I think it is very important to bring the
economic aspect in. I think it is also important that this has
got to be decided within Europe, this is not a UK problem, in
fact, it is a western, developed-world problem, and it is a problem
to do with where the import/export of livestock occur. And it
would be sensible, in light of our experiences, to look very broadly
at these issues, absolutely right.
Chairman
246. Professor Anderson, we have talked a lot
about vaccination strategies, and, of course, there are various
strategies, it is not simply a vaccination option, there are a
number of them. In your modelling, are you able to build in the
intervention of particular forms of vaccination, at certain stages
of the disease, and to come up with an idea of the efficacy of
it?
(Professor Anderson) Yes, we are, and in the first
paper—we considered vaccination, by the way, from day one,
post the consideration of the time delays of the index premise
removal, for the simple reason that the group has a lot of experience
in designing mass vaccination programmes for humans, the problems
are somewhat similar in terms of concept. And in the paper published
in Science, in April, there is a consideration of a variety of
approaches to immunisation and comparative analyses of their effect
versus culling. Dr Grenfell, more recently—it is easier
to do these things with hindsight, it is more difficult to do
them on a very fast timescale, we had two weeks to do this—is
doing a more detailed analysis of a subtle variation of looking
region by region and mini outbreak by mini outbreak, how effective
immunisation would be versus culling; and the unpublished results
of that, to date, as Dr Grenfell mentioned, are, broadly speaking,
because of the properties of the current vaccine, and he has taken
optimistic assumptions about those properties, that, still, there
are many question-marks surrounding the effectiveness of it. That
is unfortunate, and what is required, as I think Professor King
said, is a careful look at how we can use the modern technologies
of vaccine development for many different strains of the virus,
in medical terms these are called multi-valent vaccines, and just
recently there have been enormous scientific strides in producing
multi-valent vaccines for pneumococcal and other diseases; that
technology needs to be applied in the veterinary area, we need
to have a better vaccine.
247. So a significant part of the debate then
about vaccination, and particularly the people who claim that
vaccination would have offered the complete answer, as it were,
in terms of the scientific, perhaps availability, but certainly
its readiness, then, quite frankly, that is an argument which
is relevant? There never was a plan B, is what I am trying to
say, was there?
(Professor Anderson) There was a plan B. Vaccination
was considered, as shown in the minutes of the OST Science Group
meeting, virtually at every meeting; scientific questions were
raised, answers were sought, it was on the table from day one,
and it was predicted to be less effective.
248. If you had been present, you may well have
been present, if the Prime Ministers says, "Well, Professor
Anderson, I'm under terrible pressure here to vaccinate, I've
got St James's Palace at one end and farmers down in Devon at
the other end," that was quite a good shot in the dark, that,
I think, "But I have to tell you that, if you think you are
going to find a much easier way out by vaccination, it just is
not true," that would have been the nature of the advice
you would have given on this?
(Professor Anderson) The scientific advice was exactly
that. It is based on three factors; it is important to get these
correct. One, the properties of the individual vaccine; two, the
logistics, do you have the manufacturing capability, do you have
the vaccine available; and, three, a very important epidemiological
consideration, which is, if, instead of culling the ring, I immunised
the ring, as Professor King mentioned, already you have got 17
per cent transmission there, if you deliver the vaccine to an
already infected animal, the experimental evidence suggests that
it does not prevent fulminating infection in that animal, and
therefore the virus spreads to the subsequent ring. So it was
a very reluctant decision, because I think everybody would have
liked to have used different routes, if there had been an effective
other route.
Diana Organ
249. You have laid before us the option which
was used, the cull and the contiguous cull, the option of maybe
not using vaccination, or whatever; what about the other option,
because you said, on Newsnight, "We wanted to avert
a complete disaster"? I would suggest to you that in those
rural areas that were hit by foot and mouth it was a complete
disaster, and particularly to their tourist industry, if nothing
else. What about if we had done nothing, because we are not talking
about, as Eric was saying, human health here, we are talking about
animal health, what about if we had done nothing?
(Professor Anderson) I refer you to page 545 of the
Nature paper in October, which gives some risk maps, based on
livestock densities for the UK, a very detailed analysis of that;
there are scales of disaster, this is a higher order scale of
disaster than what actually did happen. And I could not agree
with you more, totally devastating. I live in an agricultural
community in Gloucestershire; totally devastating, but it could
have been far, far, far worse.
250. On the basis that you are saying it could
have been far, far worse, because the question has to be that
we have always started from the premise that this disease came
from the beginning of Heddon-on-the-Wall going to Essex; but there
are some people around that say, "Oh, no, no, no; we've had
little bits of this knocking around for a long time, and that
in sheep it's very difficult to tell the difference between orf
and foot and mouth," how do we know, from the beginning of
your modelling, that you are not looking at the beginning of an
upright curve, that actually is the sort of tail end of something
that has been going on a lot longer?
(Professor Anderson) I have had a lot of comments
like that from farmers, anecdotal evidence, that, of course, it
was around, even the suggestion that Christl Donnelly published
her paper in year 2000 about foot and mouth and speedy action
because she already knew it was there: complete rubbish, in my
view, to be honest. Foot and mouth, if present, even in sheep
where it is clinically difficult to diagnose, given our stocking
densities and movement patterns, it would have exploded, as it
did, in cattle, and even perhaps in pigs, and it would have been
very transparent. Now determining the precise point of entry prior
to 20 February, of course, the starting-point of any epidemic
is always very difficult, whether it is HIV, FMD or BSE, and you
are never going to know with precision, it probably was at least
ten to 20 days prior to 20 February, but I cannot be more certain
than that.
251. Thank you for dispelling the urban myth
that it has been around for at least a year before.
(Professor Anderson) I think the screening and testing
side of this is important, in medical epidemiology you use serological
testing; today there are extraordinarily precise methods. If I
had a bit of saliva from you all in this room, I could tell your
entire infectious disease history!
252. Do you want us to spit in the cups? From
here, that is a little tricky.
(Professor Anderson) On a bit of blotting-paper. And
I think these technologies, hopefully, will come in very strongly
into the veterinary fields; and everything lies in quick, accurate
diagnosis. And, in our current fears about other problems, that
is equally important.
Mr Martlew
253. Just a point, going back to vaccination,
obviously, the earlier witnesses gave the same information about
vaccination, but, in reality, in Cumbria, it was recommended by
the scientists; now the scientists now say, "Well, it wouldn't
have worked anyhow." But the reality is, it was recommended
by the scientists and it was turned down by the politicians. So
how can you say that the scientific advice was not to vaccinate
when in Cumbria it was, of course?
(Professor Anderson) The scientific question came,
and it was from DEFRA, and it was a very important concern that
was raised, here we have the husbandry problem that in April to
May cattle are turned out on fresh pastures to boost milk yield,
etc., etc.; is this a real danger for foot and mouth, number one,
and number two what options are available to minimise that risk.
One was, keep them in the cattle sheds for a longer period, which
was adopted; two was immunise the turnout cattle, because they
are very valuable. So we were asked to look at immunisation of
the cattle and to address two questions, would it minimise risk
of spread, one; two, how many animal lives would it save. And
we provided a set of scientific scenarios, as best as we could
at that time, concerning those issues. There was never a clear
scientific recommendation, it is not my place to do that, it is
OST's to do that to COBRA, David King's; we just looked at the
scientific options.
254. But the recommendation was to vaccinate?
(Professor Anderson) The recommendation was that it
could save animal lives, but not many, and that there was an associated
risk with it.
255. But, sorry, that was what Professor King
said?
(Professor Anderson) Professor King said, he posed
the question how many animal lives would you save, to us, and
it would have saved animal lives, but there were considerable
risks attached to it, which he did mention, about jumping outside,
because the vaccine was not very efficacious.
256. But the recommendation from the scientists
and the Government was to vaccinate?
(Professor Anderson) It is best that you put that
to OST. My role is to do the scientific work.
Chairman
257. When you were discussing this, when we
talk about vaccination, the first argument, broadly, against it
was that our whole disease-free status would be at risk; then
the argument was that farmers would not have it. The next time
it came round the argument was that the consumers would not have
it. As a scientist, did you wonder whether politicians were finding
bad reasons for things they believed by instinct, or how do you
analyse a political response to your recommendations?
(Professor Anderson) The scientific advice that went,
which is in the minutes of the meetings, was that immunisation,
even with all its imperfections, given the properties of the vaccine,
could save, in cattle turnout situations, some animal lives, but
only if the compliance, in other words, the uptake of the vaccine,
by the farms that needed to be vaccinated, was moderate to high.
Then the question comes, which is best directed to the National
Farmers' Union and the other landowning associations, would the
uptake of vaccine have been high; that is a policy question to
which I am not aware of the answer, but my impression was that
the Government followed, and this is only an impression, very
carefully the scientific advice. So it was not for political spin
purposes, it was on the basis of how best to quickly deal with
this FMD spread problem.
258. Can I conclude by looking at another, a
related issue, but one which sometimes gets a bit overlooked;
two issues, in fact. We are now, of course, doing all the serological
testing in order to declare disease-free, or virus-free, as Mr
Scudamore would say, and what we are discovering is that, here
and there, there is some old disease. Now at the beginning we
were all told that if animals got foot and mouth disease it was
an absolutely ghastly thing and you could not possibly let them
live through it because it was all too nasty. It looks like sheep
can get this and sort of shake it off, does it not? If you find
old disease in sheep in the Pennines now, for example, does it
matter?
(Professor Anderson) I think it does matter, it matters
obviously in terms of the foot and mouth fear, it is under the
current legislation or rules for the European Union. But we only
sub-sample the population. Say you have got N thousand sheep spread
over a large area, you take some sub-sample of them, typically
designed to detect a 1 per cent prevalence; the fact that you
get some positives, which are old infection, does not necessarily
mean that you do not also have some active infections, because
it could be slowly spreading through that particular region.
259. So, at the moment, when they do find some
old infection, they cull, so that is the correct thing to do?
(Professor Anderson) In my view, yes.
|
