Examination of Witnesses (Questions 280
- 299)
MONDAY 15 OCTOBER 2007
PROFESSOR DOUGLAS
YOUNG AND
PROFESSOR GLYN
HEWINSON
Q280 Mr Drew: Is that not the whole
point of what I thought we were trying to do with the badger vaccine
trial, to look at the licensing arrangements, to see if it makes
a difference? Obviously we are testing the badgers because there
is no point in trying the vaccine on them unless we are able to
look at the numbers with TB and the numbers not with TB. To me
it would seem pretty obvious that you have to roll that forward.
There is an argument about whether you do it intensively in the
same area or whether you do a comparison and slightly different
things in the comparison to tweak it to see if this makes any
difference. Again, it is this thing about time, we always seem
to be looking for another reason why we can have another experiment
which can then give us even more definitive evidence rather than
say, "Look, this is costing the taxpayer, let alone farmers,
millions of pounds every year. It is causing grief beyond any
normal expectation." If plan B is the vaccine route, and
we have not yet managed to define that there is a successful let
alone an acceptable plan A, why do we not go for it?
Professor Hewinson: I think that
is what I was saying. Once you have licensed it you can go for
it and then monitor how well it works so that would give you an
extra tool that you can use. You will have to think how best to
use it and monitor how effective that is or otherwise you spend
those resources doing a large field trial which may give you some
evidence in 5 to 10 years time.
Professor Young: What we need
to measure is what happens in cattle.
Q281 Mr Drew: Yes. We are doing that,
are we not?
Professor Young: We are increasing
our knowledge about what is happening in badgers but at the end
of the day, whatever happens in badgers, is that sufficient to
stop the badgers spreading the disease to cattle.
Q282 Mr Drew: We are measuring both,
we are measuring badgers and cattle.
Professor Young: I do not think
we have got big enough. In the badger vaccine trial I do not think
we have a big enough study that we would expect to see a big impact
on cattle. We need to roll it out to a larger study area.
Q283 Mr Drew: That again begs the
question why are we not doing a bigger study. We will come on
to that.
Professor Hewinson: Because it
was set up as a safety trial, not an efficacy trial.
Mr Drew: I am aware of that. These are
nice terms but people are holding a lot of hope out that this
is going to provide some good definitive evidence for the first
time.
Q284 Mrs Moon: Perhaps I am just
a simple townie, I do not understand why we are running out a
trial which says, "Yes, it is safe in the countryside if
we do not know that it works". That seems like nonsense to
me. Given the amount of money that is pouring into this, I do
not understand why we are not looking at the efficacy at the same
time. I would hope you are going to have some indication of the
efficacy. It might not be the full report that you might go on
to do but I would hope that what we do not get is, "Yes,
it is wonderfully safe but we do not know if it works". I
would hope we are at least going to get a result which says, "Yes,
it is safe for the field and it looks as if we have got at least
an 80% but we need to do more research that would confirm that".
Is that what we are going to get to or are going to get to, "We
do not know at all if it works"?
Professor Hewinson: What you will
get to is you will have experimental data which tells you that
the BCG does protect badgers and that is in an experimental situation.
BCG in most animals does reduce TB quite considerably when they
are challenged with the organism and when they are given an experimental
infection. That is what you need to license it. There is evidence
that it works, how well it works in the field is a different question.
You may get some indication in this trial of how well that works,
I am not convinced that you will get statistically robust data
to tell you how well it works, but one of the things which would
come out is, "Yes, we need to increase the size of the trial
to get statistically robust data".
Q285 Mrs Moon: Should we be increasing
the size of the trial now? Would that make the trial have greater
validity? Is that the route that we should, as a Committee, be
pressing on to Defra? Is that a route which would mean that at
the end of however many years, towards 2010/2015, whatever, we
will have something that is a lot more concrete? Would that be
more useful?
Professor Young: That was this
question of having more trial sites which I responded to favourably
because I would like it to have more statistical relevance but
the other way of thinking is what I really want to know is what
will happen in cattle, which is the next stage of it. Maybe we
should try, as quickly as possible, to get our indications that
it is working in badgers, get a licence and then try and roll
that out into a study, and use monitoring I would say where we
would look at cattle breakdown in some larger geographical area
that we would roll out this vaccine into.
Q286 Mrs Moon: How are you going
to look at the success of the vaccine in the field and its impact
on wildlife? How will you know it is working? What about other
wildlife such as deer, are they going to be excluded? Are you
going to be monitoring them at the same time, what is happening
there? A big sigh!
Professor Young: The current vaccine
we are using is where you trap the badgers and inject it and there
it is unlikely other wildlife are not going to pick up that vaccine.
One of the issues that the licensing people want to know is do
the badgers shed the BCG after we have injected them and we do
not think they do but we are looking at that. Where we would like
to move to, because it is a more useable tool, would be one you
would give orally so it would make some oral formulation of BCG
that you could throw about the countryside in the form of bait.
Q287 Mr Drew: Which is what the Irish
are using?
Professor Young: No, the Irish
have got an oral one but they trap them or they snare them and
then deliver it orally but they do not have a bait formulation.
When we get to the stage that we have an oral vaccine that we
could distribute that way then we need to think very carefully
about what other animals would pick that up, including cattle,
and it becomes a bigger issue that way.
Q288 Mrs Moon: If you get into the
dog walker population you would be in real trouble.
Professor Young: Yes, you would
need to be very careful about those things.
Q289 Mrs Moon: Yes.
Professor Hewinson: In terms of
your question about how you might monitor how effective it is,
in the badger population you can look at the immune response to
see if they have become infected or, as the New Zealanders have
done in their vaccine trials and how the Irish are planning to
look at it in their trial issue, kill all the animals at the end,
post-mortem them and see how many had the disease and how many
did not have the disease. That is probably your best way of knowing.
Q290 Mr Drew: Sorry, can you say
that again?
Professor Hewinson: The way that
New Zealand has looked at the effect of the vaccine in their possum
field trial and the way the Irish are planning to look at the
effect of BCG in their badger vaccine trial is to vaccinate over
a number of years and then to kill their whole population that
they have vaccinated and not vaccinated in the whole area and
looked to see how much TB is in their control animals compared
with how much TB is in their vaccinated animals.
Q291 Mrs Moon: Is that what you are
planning to do?
Professor Hewinson: Not at the
moment, no. At the moment we are following the immune responses
of the animals to see how many immune convert and how many do
not so that gives you a good idea of how much protection there
is, or not. The committee will look at this trial at the end to
see whether the indications from the immunology are enough or
whether you do need to do that.
Q292 Mrs Moon: If I can just ask
one final question to get it clear in my head. At the moment you
are going for the trapping and injection route.
Professor Hewinson: That is the
fastest route to get another tool into the field to try and control
TB.
Q293 Mrs Moon: I appreciate that.
In the longer term, if what you put together in terms of the BCG
formula that you are using, if we are thinking about rolling it
out across the country then it is going to have to be in the bait
form, I assume.
Professor Hewinson: Yes.
Q294 Mrs Moon: At the same time you
are working on how you can introduce bait or are you concentrating
on the vaccine and if that proves to work you will then look at
the baiting at a later date or are you going to try baiting at
the same time within this trial?
Professor Hewinson: We are working
in parallel so, yes, we are working with the people in New Zealand
and Ireland on the oral vaccine formulations. We are trying to
work out what would be the best baits for badgers, what would
be the best way they would take up that vaccine.
Q295 Mrs Moon: What is the food source
that they will go for most.
Professor Hewinson: Yes, exactly.
Q296 Mr Drew: Maize!
Professor Hewinson: There are
a number of things. They like ground chicken meat. We are looking
at that in parallel, but if the injectable vaccine does not look
as if it is having an effect then oral vaccination obviously would
not have an effect.
Mrs Moon: Given the lack of experts that
you have talked about, I cannot see that we have enough to run
a vaccine trial across the country.
Mr Drew: I will take that as a comment.
Q297 David Taylor: A moment or two
ago you were referring to work being done in Ireland and New Zealand.
I think there is also work being done in the United States inevitably
and in Ethiopia. How are you liaising with the research that is
happening in those countries to feed it into your own priorities
and work programme?
Professor Hewinson: In both the
cattle and badger vaccine programmes, those collaborators are
written into the grant proposals so they are working very closely
with us. In fact, some of their work is funded by Defra in terms
of badger oral vaccine development, in terms of testing cattle
vaccines and in terms of support for collaboration between countries
in their research programmes.
Q298 David Taylor: How does this
influence the priorities and timetable work of the Vaccines Advisory
Group?
Professor Young: That is quite
often an agenda item and there will be a report on these international
links.
Q299 David Taylor: The research that
has been done in those four countries I have mentioned, are there
other countries who are doing anything to any substantial extent
and where are they getting the resources from to undertake that
research?
Professor Hewinson: I would say
that the main players in terms of the vaccine development for
bovine tuberculosis are New Zealand. They have focused on cattle
and wildlife vaccines, possum vaccines, and from their work this
oral formulation is looking very promising. Initially it was developed
for possums but it is now being testing in Ireland and it is also
being tested in the United States in deer. All those trials look
promising in terms of the oral vaccination formulation they have
produced. It seems to be as good, or almost as good, as injectable
vaccines. Most of the funding from New Zealand is funded by the
Animal Health Board in New Zealand, although Defra funds some
of the cattle vaccine work and is also funding some of the oral
vaccine development work in Ireland. In the Republic of Ireland
most of the funding comes from the Republic of Ireland and in
the US the USDA funds the US work.
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