Polio: Causes and Effects, Part I
We saw in our first  blog on polio that infection with this virus was common, but paralytic polio was rare. In our second  article we reviewed the history of polio and the significant number of cases of paralysis from other causes which were blamed on polio. In the third  article we looked at one of the explanations for the rise of paralytic polio in advanced countries and the collapse of this explanation as polio increased in developing countries.
With polio, is there one cause, the virus, and one effect, paralysis? Obviously not, as the results of infection with the polio virus range from absolutely nothing to death. In this series we are going to review some of the factors which, combined with the presence of the virus, can move the situation from no symptoms and no problems, to paralysis.
A characteristic of infection with polio is the length of time it takes to clear the virus from the body and create immunity to polio.
…the interval between initiation of infection and appearance of CNS signs may be as long as several weeks, which accounts for the great variation in the incubation period of the disease. 
CNS means inflammation of the central nervous system. Someone can be carrying around a happily multiplying polio virus in the nose, throat and gut system, and other non-neural areas of the body, for a period of weeks without having any symptoms to indicate that the virus is there. “Non-symptomatic response” to polio virus exposure, results in eventual clearing of the virus from the system, permanent immunity to that strain of polio, and is the normal bodily response to the polio virus.
However, if something occurs during the several weeks of polio virus carriage which opens up access to the central nervous system to the virus, then the polio moves from asymptomatic to paralytic. There is a list of provokers which cause polio to invade the CNS. Today we are going to consider one cause which we can credit to the medical profession.
Provocation polio due to vaccines or other injections: the third item on the chart of types of acute flaccid paralysis is “vaccine-associated paralytic poliomyelitis.”  Yes, vaccines can cause paralytic polio. In fact injections of many different drugs such as anesthetics, antibiotics, etc, can cause paralytic polio.
A study which clearly demonstrates this phenomena and which changed vaccination practices in the U.S. is here :
This investigation corroborates the published findings of other investigators that there is a relationship between recent inoculation with diphtheria toxoid, tetanus toxoid or pertussis vaccine (DPT) and the development of paralytic poliomyelitis. This is indicated by the fact that a significantly larger percentage of children was paralyzed in the injected limb when the last injection had been received not more than a month preceding onset of poliomyelitis than when received from a month to a year before.
Other injections can also provoke paralysis from the virus.
…enhanced risk of paralytic manifestations that follows intramuscular injection, and it occurs when inflammation in muscle coincides with poliovirus infection; entry of poliovirus to nerve endings in the muscle is facilitated, and paralysis occurs 4—30 days later. 
The oral polio vaccine is also associated with paralytic poliomyelitis. The role of intramuscular injections in the Romania polio outbreak resulted in an extremely high number of cases of vaccine associated polio:
The strength of the association between intramuscular injections and vaccine-associated paralysis was similar for the vaccine recipients and the children who acquired the disease by contact, as was the dose-response effect. For cases in vaccine recipients, the timing of intramuscular injections with respect to the receipt of OPV was critical; injections administered after the receipt of OPV, but not before or at the same time as OPV, were associated with elevated risk. In addition, our finding are similar to observations in the late 1940s and 1950s that intramuscular injections have a tendency to “provoke” paralysis in the injected limbs of persons infected with wild-type poliovirus. This association was particularly noticeable in the United Kingdom, where DTP was injected into the arm and there was a reversal in the ratio of arm involvement to leg involvement among children with paralytic poliomyelitis. (emphasis added) 
While this information was readily available in the literature. children in Romania suffered unnecessary paralysis from 1970 until nearly 1995, (around 25 years) because scientists were seemingly incapable of reading their own literature and spotting a known and obvious explanation for the problem.
The historical increase in polio in western countries, as we saw in our last article, was blamed on improved sanitation, one of many factors which change when developing countries modernize. Another overlooked factor, despite the extensive documentation in the scientific literature, is the arrival of injections with western medicine. For example, Samoan children ended up with paralysis from injections against yaws:
The 1936 report by Lambert of a severe epidemic of paralytic polimyelitis among Samoan children inoculated with neoarsphenamine for yaws provides a good example not only of one way in which “civilization” may contribute to the increase of paralytic poliomyelitis, but perhaps also one of the earliest incidents suggesting the role of inoculations at a time when a virulent virus is widespread. The Samoans believe that the neoarsphenamine injections were responsible for the paralysis, while Lambert and his associates thought it was pure accident, since the disease was typical of poliomyelitis. 
In the U.S. vaccinations were introduced very gradually from 1900 to 1940, when the pace picked up.  With each increase in the use of vaccination (and other injected medications) came increased opportunities for vaccine provoked polio.
Articles in the medical literature indicate that provocation paralysis continues to occur, from the combination of OPV and subsequent intramuscular injections and from the use of injections in areas where the polio virus is still circulating. The inability of doctors and scientists to read and comprehend their own scientific literature continues to cause cases of paralysis.
Examples of provocation polio:
Provocation of poliomyelitis occurred in 66% of children and usually followed intragluteal injections associated with treatment of non-specific fevers…The risk factors identified in our study are lack of immunization and administration of intramuscular injections during the pre-paralytic phase. [ 10]
and an outbreak in 1999-2000 shows that the beat of unnecessary paralysis moves on and on.
With little difference in the vaccination status of cases and controls, the only clear risk factor for type 3 poliomyelitis in this study was having at least one injection in the month prior to paralysis onset. 
Injections are an immensely popular form of medical treatment in developing countries and delivered not just by trained personnel but by traditional healers and by family members. As we outlined in our article Medical Double Standards in the Third World, carelessness with needles means that millions of reusable needles are available to people with no clear idea of how to use them safely or appropriately. As shown above, even medical personnel seem to be unclear on the dangers of giving injections in the month following a dose of the oral polio vaccine, or when poliomyelitis is circulating in the community. Vaccine provoked poliomyelitis has not ended and may not end for many years to come. After all, letting the general population know that injections are dangerous might keep people from getting their good shots:
In planning to reduce the number of unnecessary injections it is important to avoid negative effects on people’s perceptions of vaccinations and contraceptive injections. 
Misinformation about the potential danger of vaccinations is a worldwide problem.
For more information on provocation polio: Mechanism of Injury-Provoked Poliomyelitis, Matthias Gromeier and Eckard Wimmer. Journal of Virology, June 1998, p. 5056-5060. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC110068/pdf/jv005056.pdf
 Polio 2010. Inside Vaccines. May 26, 2010. http://insidevaccines.com/wordpress/2010/05/26/polio-2010/
 Polio and Acute Flaccid Paralysis. Inside Vaccines. June 2, 2010. http://insidevaccines.com/wordpress/2010/06/02/polio-and-acute-flaccid-paralysis/
 Polio and Sanitation. Inside Vaccines. July 1, 2010. http://insidevaccines.com/wordpress/2010/07/01/polio-and-sanitation/
 Epidemiology of Poliomyelitis and Allied Diseases – 1963. Dorothy M. Horstmann. The Journal of Biology and Medicine, 1963, 36, 5-26. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2604573/pdf/yjbm00599-0011.pdf
 Differential Diagnosis of Acute Flaccid Paralysis and Its Role in Poliomyelitis Surveillance, Arthur Marx, Jonathan D. Glass, and Roland W. Sutter. Epidemiologic Reviews, Vol. 22, No. 2, 2000 http://epirev.oxfordjournals.org/cgi/reprint/22/2/298.pdf
 The Relation Between Recent Injections and Paralytic Poliomyelitis in Children. Morris Greenberg, Harold Abramson, Helen M. Cooper and Helen E. Solomon. American Journal of Public Health, 1952, 42, 142-152. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1525737/pdf/amjphnation00407-0031.pdf
 Intramuscular Injections Within 30 Days of Immunization with Oral Poliovirus Vaccine – A Risk Factor for Vaccine-Associated Paralytic Poliomyelitis. Peter M. Strebel, Nicholae Ion-Nedelcu, Andrew L. Baughman, Roland W. Sutter, and Stephen I. Cochi. New England Journal of Medicine, 1995, 332, 8, 500-506. http://www.nejm.org/doi/pdf/10.1056/NEJM199502233320804
 Paralytic Consequences of Poliomyelitis Infection in Different Parts of the World and in Different Population Groups, Albert B. Sabin, American Journal of Public Health, Vol. 41, Oct. 1951. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1525657/pdf/amjphnation00428-0010.pdf
Historic Dates and Events Related to Vaccines and Immunization. Accessed on September 12, 2010. http://www.immunize.org/timeline/
 Poliomyelitis: 20 years–the Pondicherry experience. Mahadevan S, Ananthakrishnan S, Srinivasan S, Nalini P, Puri RK, Badrinath S, Rao RS. The Journal of Tropical Medicine and Hygiene. 1989 Dec;92(6):416-21. http://www.ncbi.nlm.nih.gov/pubmed/2558226
 Outbreak of poliomyelitis due to type 3 poliovirus, northern India, 1999–2000: injections a major contributing factor. Kathryn A Kohler, W Gary Hlady, Kaushik Banerjee and Roland W Sutter, International Journal of Epidemiology, 2003, 32, 272-277. http://ije.oxfordjournals.org/content/32/2/272.full.pdf+html
 Anthropological Perspectives on Injections: A Review. A. V. Reeler. Bulletin of the World Health Organization, 2000, 78, 135-143. http://www.who.int/bulletin/archives/78%281%29135.pdf