INTERNATIONAL
Not yet out of the woods
Don’t expect a bird flu vaccine to be
available any time soon
A Thai expert writes reference numbers on an egg for tests at
a laboratory in Bangkok on February 1. —
AFP |
Happily, the avian (bird) flu situation
seems to have improved a bit over the past two months, so it has
not been such a big item in the news. However, health officials
around the world are still extremely worried that a virulent
new strain could develop that could spread easily from human
to human. That, they say, could result in tens of millions of death
worldwide.
If such an outbreak
does occur, there is a strong likelihood it would begin in
our part of the world, perhaps right here in Thailand. The close
proximity between chickens, ducks, farm animals and humans
makes this an ideal laboratory for the current bird flu virus to
mutate.
While some kind of
bird flu epidemic seems almost inevitable, researchers
are working frantically to develop weapons to keep it under
control. One project of particular interest has just begun in the
US. There, scientists have started human trials of an experimental
avian flu vaccine.
Last
Wednesday, 150 healthy volunteers received injections of the vaccine
and another 300 are scheduled to receive theirs shortly. Interestingly,
the vaccine is based on a genetically engineered copy of
a virus sample isolated from a Vietnamese patient last year.
It
is important to realise that this is only what is known as a “phase
1 trial”. It is therefore not designed to determine if the vaccine
works, but to only see if it is safe — i.e., that it does not cause
any dangerous reactions or side effects. Thus, it could be
quite some time until we know if this vaccine can actually prevent
the disease.
Then
there is the equally time-consuming matter of producing enough
of it to reach those in need. Unfortunately, this vaccine is being
manufactured using the same old-fashioned process that has been
in use for decades. It requires specially grown eggs that need months
of incubation. Since each egg produces only a single dose
of vaccine, it could be well over a year before significant supplies
of the vaccine get in the distribution system.
To
speed things up, the US government recently awarded $97 million
to drug-maker Sanofi Pasteur — the same company involved in the
experimental bird flu vaccine — to develop a new production method
in which the vaccine could be grown in laboratory dishes. If this
technology works — a big question mark — it could cut production
time in half.
Unfortunately,
even if a vaccine is produced that is effective for the current
strain (H5N1), there is no guarantee that it would work against
a new and different strain. Vaccines normally have to be tailored
to a particular virus and for that reason we really can’t stockpile
them.
That
is why preventative measures are so important. After her stint
as public health minister, Thailand’s new agriculture minister,
Sudarat Keyuraphan certainly knows this and we should be watching
very closely to see what kind of a system she puts in place to keep
our agricultural sector healthy.
It
will be interesting to see if she allows the use of a bird flu vaccine
for chickens and ducks. Chinese scientists recently announced that
they had produced two such vaccines that offered up to ten months
of protection. Few details have been made public, however. Watch
to see if more information is forthcoming
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out
of the woods
out of danger
virulent
extremely dangerous or harmful and quick to have an effect
strain
a particular type of plant, animal, virus or bacteria
outbreak
a sudden start of something unpleasant, especially a disease
or violence
likelihood
the chance of something happening; how likely something is
to happen
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roximity
nearness
mutate
to change into a new genetic form
epidemic
a large number of cases of a particular disease happening
at the same time and in the same area
inevitable
that which is certain to happen
frantically
done quickly with a lot of activity
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genetically-engineered
deliberately changed at the level of the genes
isolated
(of a single substance, cell, etc.) separated from all others
side-effects
extra and usually bad effects from a drug other than the effects
intended
time-consuming
taking a lot of time
incubation
the process of keeping cells, bacteria, etc. at a suitable
temperature so that they develop
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dose
an amount of a drug that is taken once
tailored
made for a particular purpose
stockpile
to collect and keep a large supply of something
stint
a period of time spent doing a job
forthcoming
made available
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