FIP Congress 2006
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Better use of seasonal influenza vaccines would
prevent unnecessary deaths and would have the effect of increasing
global vaccine production capacity in preparation for a pandemic.
Graeme Smith (on the staff of The Journal) reports from a
session organised by the Military and Emergency Pharmacy section
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 The World Congress of Pharmacy and Pharmaceutical Sciences,
the 66th International FIP Congress, was organised by the International
Pharmaceutical Federation in association with the Federal
Council of Pharmacy of Brazil.
It took place in Salvador da Bahia from August 26 to 31, 2006
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Better use of seasonal flu vaccines is essential for
pandemic preparedness
If seasonal influenza vaccines were used better, it would reduce death
and disease and, in a natural way, would bring up production capacity
for influenza vaccines, which is currently lacking in pandemic preparedness,
said Bram Palache, global scientific communications
and public affairs director at Solvay Pharmaceuticals, the Netherlands.
Quoting
the World
Health Organization, he said: “You can’t ask for production
during an emergency if there is no production capacity during peacetime.”
He told the session that it is generally assumed that, at the onset of
an influenza pandemic, there would be no vaccines available to immunise
and protect the population and that governments would have to rely on
stockpiled antiviral agents.
However, recent research efforts suggested
that there are possible strategies to be less empty-handed at the onset
of a pandemic than assumed so far.
Mathematical models and animal studies indicate that a pre-pandemic
stockpiled influenza vaccines may offer adequate levels of immunity
and protection
to dampen the consequences of an avian influenza pandemic.
Dr Palache said that no one know if a pandemic will occur, but ignoring
the problem will not make it go away. There is an urgent need to be
prepared because of the disastrous consequences, should a pandemic
happen. Pandemic paradox
Dr Palache described described what he called the pandemic paradox.
Worldwide, seasonal influenza is preventable but, generally, is not being
prevented.
Currently, available influenza vaccines are underused, he said, resulting
in around half a million unnecessary deaths each year. The vaccine
for seasonal flu fails to reach many elderly people and other people
at risk who suffer from chronic diseases. However, fear of future deaths
during an avian influenza pandemic is driving people’s interest
and the need for countries to be prepared.
The paradox lies in the fact that, because countries are not using
the available seasonal vaccines, industry’s capacity to produce vaccines
is being held in check. Once the WHO declares a pandemic and releases
seed vaccines, governments will want to have vaccines that can be administered
to be available as quickly as possible. But the industrial capacity to
do this effectively simply does not exist.
The industry, said Dr Palache, currently produces vaccines in response
to the demands of the market and not necessarily its needs. It is clear
that shortfalls in vaccines can lead to a public health crisis but, on
the other hand, production of more vaccines than are demanded means an
economic loss. So, if currently available seasonal vaccines were used
more appropriately, demand for them would increase and, therefore, production
capacity would increase.
There is no point in increasing capacity to
produce vaccines that are not used. Therefore, the industry’s capability
to produce vaccines in a pandemic depends largely on how seasonal influenza
vaccines are used now, Dr Palache declared.
He went on to tell the meeting that the current manufacturing capacity
of trivalent flu vaccines stands at 300 million doses in 10 months, with
a production lead time of two to four months. In unprimed populations,
a single dose of such a vaccine would not be sufficient to provide adequate
protection. Recent research has suggested that at least two doses of
four times the normal strength would be required. Therefore the need
for a high-dose pandemic vaccine compromises global production capacity,
said Dr Palache.
By lowering the effective dose required,
more doses of vaccine could be produced using existing production capacity.
So the challenge for the industry and for research
organisations, in order to fulfil global pandemic vaccination objectives,
is urgently to develop effective low-dose vaccines. That research is
currently being carried out all over the world, with 70 per cent of it
happening in Europe.
He outlined global vaccine supply estimates based on different pandemic
vaccination strategies. With capacity the way it is, the available global
trivalent vaccine production capacity is 300 million 15µg doses.
In a pandemic situation, where one 15µg monovalent dose may be
required, 900 million people could be vaccinated, but if two doses were
required (ie, a booster) the supply is effectively halved and only 450
million people could be vaccinated. If the dose could be reduced to 7.5µg
and a booster were required, 900 million people could be protected.
Dr Palache said that Glaxo had recently presented data which showed that
two doses of 3.8µg could be effective as a pandemic strategy. If
this could be translated to all vaccine manufacturing companies worldwide,
then overall production could amount to 1.69 billion doses using existing
manufacturing capacity. Such a move could not be made today, he said,
but the fact that it might be possible is a major step forward in preparations
for a pandemic. He stressed the need for careful planning.
He went on to describe some preparedness scenarios. One was to stockpile
H5N1 vaccines, but there were supply issues here and possible mismatches
with any pandemic strain. Some countries may make advance purchase agreements
and reserve vaccine production capacity, he said; in such a case, after
one year it would be unlikely that there would be any vaccines available
for other parties so, again, careful planning is essential. Primary goal
The primary goal of a pandemic influenza vaccine must be to prevent
death and not necessarily to prevent infection. He referred to a mathematical
model which suggested that available vaccines, even if poorly matched
to circulating strains, could significantly slow disease spread.
Animal
studies have confirmed that mathematical model. So, it could be concluded
that a strategy of stockpiling pandemic vaccines for administration
to groups at high risk does indeed offer promise.
Concluding, Dr Palache said that the emergence of a pandemic of H5N1
or any other influenza cannot be ruled out and so preparedness on a
global, regional and national scale is justified. Pandemic vaccines
are the most
realistic tools to minimise the potentially devastating effects. The
stockpiling, therefore, of prototype pandemic vaccines may be a justifiable
and prudent cautionary measure that should be seriously considered. |
The
Pharmaceutical Journal