Recent research, conducted in India, has suggested that the
Polio virus, endemic in three countries (Nigeria, Pakistan and Afghanistan),
can be more efficiently eradicated by using a combination based on the widely
used Oral vaccine supplemented with the injected form. The research therefore
recommends the introduction of at least one dose of the injected vaccine in
addition to the regular vaccination schedule.
The Research
This research was “carried out by researches from the WHO,
the US Centers for Disease Control and Prevention, Imperial College London, the
Enterovirus Research
Centre in India and Panacea Biotech Ltd”. This is important to recognise as it
represents an international collaboration and so this suggests that the
research is credible. This is because all parties involved would have to
produce consistent results and respect the end result. Hence by involvement of
national organisations and the WHO this means that all researchers would have
had to follow protocols to ensure comparative ability to produce reliable
results. Thus this suggests that these protocols were checked and affirmed and
analysed to produce valid results.
Furthermore, the trial was randomised and so this ensures that genetic
variability, for example in natural slight immunity is evenly distributed over
the two groups. This also prevents scientists from being influenced by bias to
include only the strongest individuals in the trial for example. Adding to
this, 954 children were involved and so due to this large sample, the range of
results is more likely to be representative of the entire population thus
ensuring that the data is useful. This is because it ensures that similar
results can be expected if the vaccine was extended further. It also involved
three distinct age groups: 6-11 months, children aged 5 and children aged 10.
Through use of three groups it ensured that differences in the development of
immunity could be accounted for. Hence, this meant that in the future, these
results could be used most effectively to target a specific age group and
therefore achieve maximum efficiency. The distinction between the groups was
also important as it ensured that the control group could be matched more
closely to the group receiving treatment to ensure that any response produced
by one group was not magnified or diminished because of other factors
associated with age. This meant that the results would be repeatable and hence
reliable.
These
children had already being vaccinated with the oral polio vaccine thus ensuring
protection. However, the trial compared whether giving an additional dose of
Salk IPV (the injected vaccine) would be more effective than an additional dose
of the oral vaccine. Thus three groups were established: a group receiving the
Salk IPV; a group receiving another dose of the oral vaccine to assess whether
worthwhile gains in immunity were achieved by using the IPV over the oral
vaccine; and a group receiving no additional vaccine to more easily quantify
the efficacy of either vaccine (since without this third group the gain from
the Salk IPV would only be relative to the oral vaccine and so the gains
couldn’t be assessed i.e. if the Salk IPV addition meant that 5 more children
remained immune after a period than in the oral vaccine then this may be small
and not worthwhile yet if the oral vaccine meant that 1 more child remained
immune as opposed to no vaccination, then the 5 child gain would be much more
significant). After 4 weeks the children received a dose of the oral polio
vaccine, containing dead or weakened forms of the virus. The amount of polio
virus in their faeces was then monitored to quantify the immunity of the child.
The lower the amount of poliovirus in the faeces, the greater the immunity and
hence the lower the risk of transferring the virus.
Two
types were studied, type 1 poliovirus and type 3 poliovirus. In the 6-11 month
old group it was found that booster injections of the vaccine “significantly
reduced the proportion of infants with type 3 poliovirus in their faeces
compared to no vaccine, but did not significantly alter the proportion of
infants with type 1 poliovirus in their faeces”. In the 5 year old group a similar result was
seen yet the immunity to type 1 poliovirus also increased with injections.
Finally, in the 10 year old group a similar result was seen to the 5 year old
group. However, with the 10 year olds, a booster of the oral vaccine had a
similar effect. This was not the case in the younger groups. Hence this could
suggest that immunity gradually decreases with time and so, because the 10 year
old children responded in a similar way to the oral and injected vaccines, the
increase in immunity may have simply been due to a lower general level of
immunity anyway. In contrast the younger groups produced results which
suggested an additional dose of injected vaccine was more effective than the
oral dose. Thus, this infers that an additional layer of immunity was added due
to immunity in a different area of the body. This is shown in the basic diagrams.
Assuming 30 units is the maximum limit that can be achieved with an oral
booster, in younger children that have recently being vaccinated both initial
levels are at 30 (graph 1). An injection booster can therefore raise this further (graph 2). In a
10 year old where the immunity has decline to, for example, 10 units (graph 3), a booster
using either method can have an effect as the oral vaccine is not limited (graph 4).
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| Graph 1 |
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| Graph 2 |
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| Graph 3 |
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| Graph 4 |
Cost vs. Effectiveness
This has been called a “historic” finding by the WHO yet
although the injected method of vaccine may be useful, in the past it has been
limited due to its higher cost and higher risk. For example, the benefit of the
injected vaccine is that it increases the immunity within the bloodstream which
is more useful as this supplies all areas with blood, hence immunising the
blood massively restricts the capability of the virus to multiply and hence
this increases general immunity. In contrast, the oral vaccine mainly immunises
the digestive tract. This is essential yet is arguably not as important as
immunising the blood as there is a greater risk that the virus could ‘bypass’
an immunised digestive system, yet with the blood, because it works everywhere
and is a step beyond digestion, it is more encompassing of infection. However,
the cost of needles, careful transportation methods to avoid damage to these
needles, sterilisation costs and maintaining sterilisation through hygienic
methods, is high. This means that in unstable countries that are economically
unstable, reliance on other nations is not surprising, hence this means that
the overall cost to more developed nations is higher. Alternatively, oral
vaccines can be packages with plastic and sealed it can then be transported to
health care centres in mass numbers without a fear of damage. Thus the cost is
much lower. Furthermore, oral vaccines involve no contact with anything except for
the vaccine. On the other hand, injected vaccines involve needles and so this
can introduce infection which is a particularly significant issue in these
underdeveloped countries where hygiene is not prioritised as much. Thus, the
involvement of injected vaccines can place patients at risk of contracting
other, more prevalent diseases.
Furthermore, in 1988, there were 350,000 cases of polio in
more than 125 countries. This has fallen today by over 99% and is now only
prevalent in three countries. Hence, mass development of prepared needles and
new protocols on transportation and access may be considered ‘too much’ for
such a limited disease. This is because, as the oral vaccine has dominated the
battle against polio, injected vaccines have declined and hence the
infrastructure to suddenly produce more injected based vaccines may involve
high set-up costs. Thus if the relatively small scale of the disease may not
justify this. Nevertheless, Professor Nicholas Grassly states “If you have
limited access, you want the biggest return”. This may be the reason why Polio
is still prevalent despite mass eradication schemes and international efforts:
a lack of access to the most vulnerable areas followed by insufficient vaccine
effectiveness when access is allowed. Therefore a more effective combination of
the oral and injected vaccines might allow a more efficient eradication of the
disease in limited access areas. Furthermore, it is unlikely that in the
long-term these set-up costs will be significant. This is because, these
immediate costs would be balanced by continuous savings on healthcare for
victims of the polio virus. Adding to this, if injected vaccines hasten the
decline of the disease, the overall amount of vaccine produced (oral and
injected) will decline over time hence cutting the cost of producing the
vaccine. Consequently, I don’t believe that the monetary argument is
appropriate (to deny fragile countries access to medications, I believe, is
ethically wrong) or significant. Practical Problems
Therefore, the only other important consideration about
whether this trial can be considered “historic” is whether it can practically
be used. This is an issue as some countries use vaccination programmes as a
political weapon. For example, in 2012, the Taliban banned the vaccine in the
North and South Waziristan regions of Pakistan unless the US agreed to
negotiate. This meant that the vaccine program risked opposing the government
and hence causing an international conflict. Also access to countries to supply
vaccines is limited. This is because, with a weak healthcare system, many
vaccines are given to community doctors. Thus there can be no standards testing
which means that vaccines may be viewed suspiciously by authorities.
Added to this are various misconceptions over vaccines which
some attribute to religion. Admittedly, there are some fringe groups that do
oppose vaccination however I don’t believe this can be considered valid for two
main reasons. Firstly, these religious groups that are in opposition to
vaccines can and are spread widely throughout the word. Thus, the fact that
only three countries still suffer from Polio would infer (if we were to use the
argument that religion can stop vaccination) that these countries have a
greater proportion of these sceptical religions. This is not the case. This is
clearly seen in religious statistics (50.4% of Nigeria’s citizens are
Christian) yet can also be inferred when we consider that religious ideologies
often diffuse from a point and the fact that Nigeria is so far away from Pakistan
and Afghanistan weakens my confidence that they share a strong religious
opposition to vaccines. Also, many established religions decide on modern
issues by looking at various ethical arguments as well as religious arguments.
As a result, I will consider two ethical schools of thought:
·
Consequentialism
This would appear to support vaccination as
vaccines minimise the pain of disease and hence maximise the duration of the
pleasure of life. Furthermore, as more people are vaccinated, the risk to unvaccinated
people decreases as they are less likely to come into contact with an infected
person. This is called herd immunity and means that the extent of ‘pleasure’
created by vaccination is large. Alternatively, we cannot be certain that a
vaccine would be of individual benefit (some may not come into contact with the
disease anyway). Also the benefit of a vaccine may not show until much later,
hence the pleasure is remote. Even so, I believe that the fact that vaccines
minimise pain means that vaccines are acceptable on hedonic calculus (a measure
of pleasure vs. pain).
·
Kant’s ethics and deontology
Kant believed that if you choose to perform an
action then you accept that it should become a universal maxim, i.e. if you
kill someone you accept that everyone can kill whoever they want. Vaccines
therefore may be accepted by Kant as by accepting vaccination it is perfectly
acceptable to state that everyone should be able to have a vaccination. On the
other hand, deontology argues that the intention of an action is more important
than its consequence. Thus, if the US government continued to supply vaccines
to Pakistan in 2012 to undermine the Taliban, this may be considered
unacceptable as its intention is to cause harm however slight. Nevertheless, if
we take this situation from another perspective then it could still be seen as
acceptable. This is because if not vaccinating people makes them vulnerable and
dependent on the state and unable to make rational and free decisions, then
Kant may argue that not vaccinating causes people to become a ‘means to an end’
without free choices. Thus we have a duty to prevent this – a duty to
vaccinate.
Consequently, it is unlikely that religions would be opposed
to vaccines due to the benefit that they offer.
Another area of difficulty with introducing injection based
vaccines is that it would need an outside authority to supply and administer
the vaccine. In contrast, in order for Polio to be eradication, countries must
be self-sufficient and willing to focus on the disease to eradicate it. Hence
this would require a localised effort which would be much harder to achieve
with an injected vaccine as opposed to an oral vaccine. This is perhaps the
most limiting factor in implementing the research as due to the Ebola crisis,
Nigeria’s healthcare system is debilitated and so this means that vaccination
programs would be considered to be a far lower priority. This therefore
encourages long-term dependency on other countries and would distract from a
community based vaccination scheme that would allow a vaccine to be ‘rolled
out’ and made accessible to everyone.
My Verdict
However, to conclude, I am optimistic that this research
will lead to a more effective battle against Polio and will continue to cause
the decline of the disease which has stabilised now in Nigeria at 70-80
infections every year since 2009. I am confident about this as, recently,
TechNet-21 (the Technical Network for Strengthening Immunization Services)
launched a resource to allow immunisation professionals to compare immunisation
equipment. Also, the resource will enforce equipment that has passed through
the “Performance, Quality, and Safety (PQS) programme” advocated by the WHO.
Thus this demonstrates the growing coordination and research into immunisation
projects and so will establish a greater focus on Polio which is already
encouragingly close to eradication.
Sources
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