Naked Science Forum
Life Sciences => Physiology & Medicine => Topic started by: thedoc on 27/01/2014 12:19:25
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Polio might not have been seen in Britain since the 198's, but despite worldwide efforts the potentially fatal disease is still endemic in three countries. Kate Lamble caught up with the Director of Immunisation at the Department of Health, Professor David Sailsbury as he visited St Johns college in Cambridge to speak about the global effort to eradicate the disease.
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One should point out that since 2011, there have been less than 1000 cases a year (http://en.wikipedia.org/wiki/Poliomyelitis_eradication#2013), and the number of countries listed as "endemic" is decreasing every year. This is compared to 35,000 reported, and estimated 350,000 cases in 1988. There are a few countries listed as "importation" including a large outbreak (185 cases) in Somalia last year.
I have no doubt that if eradication efforts were decreased, that there would be a rapid resurgence of the disease. Even if the disease was eradicated in all but one country, it would periodically escape.
I wonder, however, if the USA and Europe is somewhat isolated due to generally good hygiene.
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USA and Europe ... generally good hygiene.
I don't think that hygiene has improved much since the 1950s, but Polio was endemic in "western" countries in the 1950s.
What has changed is near-universal vaccination of children.
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Should we try to eradicate a single disease at a time, or go after several?
I was looking up statistics for Hepatitis A, which also has a vaccine now, and is generally an acute-only infection, causing about 100,000 deaths a year, and I believe humans are the only reservoir.
Is tetanus zoonotic? It also causes about 100,000 deaths a year, mainly in 3rd world nations.
Or, perhaps one should try to vaccinate the world with the common childhood vaccinates that we use here. Measles, Mumps, Rubella, Polio, Hep A, Hep B, tetanus, etc.
Perhaps one of the differences with Polio is the long-term health problems associated with the disease, so one not only sees those acutely infected, but also those who had been infected by the disease in the past.
While the goal of global eradication of Polio is good, there are many other diseases that cause significant morbidity and mortality around the world.
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Is tetanus zoonotic?
The Tetanus bacterium can live in soil, and in animal digestive systems, in anaerobic conditions.
The vaccination is not against the bacterium itself, but against the toxin it produces (Tetanus is related to the botulism bacterium).
So it seems that a vaccination campaign with the current anti-toxin won't eliminate the bacterium in nature.
See: http://en.wikipedia.org/wiki/Clostridium_tetani
A major scourge on humanity at present is malaria, but it has proved particularly difficult to produce a vaccine against it.
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$5.5 Billion to prevent 1000 annual cases of Polio is a lot of money. However, if the vaccination campaign was to stop, no doubt there would be a resurgence of the disease, and perhaps also hit unvaccinated adults in countries that had previously eradicated the disease.
However, how much money would be saved in North America and Europe to not ever have to vaccinate for the disease ever again?
After Wild-Type Poliovirus is eradicated, how long will it take to eradicate circulating vaccine-derived poliovirus? Is it a problem, or will it even be a priority? 5 years after OPV was discontinued in the USA, there was apparently one case of vaccine derived polio (https://en.wikipedia.org/wiki/Poliomyelitis_eradication#2005), presumably due to a circulating vaccine derived virus that was self-sustaining in the community.
Should more communities start transitioning from OPV to IPV? Or at least a combination of IPV first, followed by OPV later.