The Failure of Global Polio Eradication by Jeffrey Dach MD
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My wife loaned me an old copy of Jane Goodall's 1971 book,"In the Shadow of Man, about wild chimpanzees of the Gombe National Park. It was fascinating reading. However, I was saddened by an apparent polio outbreak in the chimpanzees which took place around 1966.(1) Left image oral polio vaccine applied to sugar cubes courtesy of wikimedia.
One day, a beloved chimpanzee appeared in camp dragging a lifeless limb. Jane assumed it was polio, since an outbreak had been reported in a nearby village. They looked on hopelessly as one after another of the chimps were stricken with paralysis, eventually affecting about half dozen. They then tried giving the chimps oral polio vaccine as a preventive measure. In spite of their efforts, two of the chimps had to be euthanized with the camp pistol.
There are many unanswered questions. For example, we don't know if the causative agent was a poliovirus, coxsackie or some other entero-virus. If a polio virus was present, we assume it came from humans, yet we don't know if it was wild type polio, or vaccine derived polio (VAPP.)(1) Perhaps the acute flaccid paralysis was caused by exposure to neurotoxic pesticide at the camp?
In Zaire in 1964, there was a similar outbreak of flaccid paralysis in chimpanzees. Observers were not sure if the etiology was a neuro-virus such as polio transmitted by humans, or exposure to neuro-toxic agricultural chemical sprays.(18) (limb paresis polio chimpanzees 1964 Kortlandt Pan African News)
Polio Vaccine Experimentation in Africa
In the preceding decade in the 1950's, there had been local vaccine experimentation with live polio virus by Hilary Koprowski in both primates and villagers in the Belgian Congo.(20-23) So, surely, there was plenty of opportunity for a virulent vaccine derived polio virus to escape and circulate in the human population.(44) Although Koprowski's publications contained glowing reports, his vaccine was never approved for human use.
Polio Vaccine Derived Paralytic Polio in Nigeria
In the 2011 Journal of Infectious Disease, Dr Wassilak from the CDC reported 336 cases of paralytic polio in Nigeria caused by the oral polio vaccine itself, which had mutated back to a virulent form. Similar cases of vaccine derived virus paralytic polio have been reported in the Belgian Congo (41-44) (see: Outbreak of vaccine-derived poliovirus in Nigeria.)
Vaccine Derived Polio in an Amish Community
This Jane Goodall chimpanzee polio outbreak reminded me of a 2005 report of an outbreak of Vaccine Derived Polio in an unvaccinated Amish community in Minnesota.(34-35)(13) Thankfully, in this human population, there was no paralysis, merely documentation of virus shedding in the stools. Molecular biology tools using reverse-transcriptase polymerase chain reaction (RT-PCR) assays, showed the virus was derived from an oral polio vaccine which had circulated in an unvaccinated community.(34-35)(13)
The Oral Polio Vaccine by Albert Sabin
I was a kid in third grade in 1958 when the whole school was lined up in the hallway. Each one of us was given a sugar cube impregnated with oral polio vaccine. This was the Polio Vaccine developed by Albert Sabin, a live attenuated virus which causes infection in the gut, but is not neuro-virulent. The recipient develops immunity to the live attenuated virus, which is also protective for the wild type polio virus.
Houston, We Have a Problem
It was soon recognized that this harmless oral polio vaccine would occasionally revert back into a neurovirulent strain, causing paralytic polio in the recipient, as well as contacts exposed to shedding virus. Here is a quote from Dr. Hull:"Mutated Vaccine Derived Polio Virus that are neurovirulent in animal models can be isolated from the stools of children within days of vaccination"(10)
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