Paralytic poliomyelitis

Fig. 16.1 Reported incidence of paralytic poliomyelitis in England and Wales during the 1950s and 1960s. After introduction of vaccination programmes the incidence of disease dropped from an endemic incidence of ca. 5000 cases per year to fewer than 10.

No medical or therapeutic procedure comes without some risk to the patient. All possible steps are taken to ensure safely, quahty and efficacy of vaccines and immunological products (Chapter 15). The risks associated with immunization procedures must be constantly reviewed and balanced against the risks of, and associated with, contracting the disease, hi this respect, smallpox vaccination in the UK was abandoned in the mid 1970s as the risks associated with vaccination then exceeded the predicted number of deaths that would follow importation of the disease. Shortly after this, in 1980, The World Health Assembly pronounced the world to be free of smallpox. Similarly, the incidence of paralytic poliomyelitis in the USA and UK in 1996 was low but the majority of cases related to vaccine use. As the worldwide elimination of poliomyelitis approaches, there is much debate as to the value of the vaccine outside of an endemic area. 

Faecal excretion of vaeeine virus will oeeur and may last for up to 6 weeks. Such released virus will spread to elose eontaets and infect/(re)immunize them. Since the introduction of OPV, notifications of paralytic poliomyelitis in the UK have dropped speetacularly. From 1985-95, 19 of the 28 notified cases of paralytic poliomyelitis were associated with vaeeine strains (14 reeipients, 5 contacts). Vaccine-associated poliomyelitis may occur through reversion of the attenuated strains to the virulent wild-... 

Poliomyelitis is a highly contagious disease that is often asymptomatic however, approximately 1 in every 100 to 1000 cases will develop a rapidly progressive paralytic disease. Polio is caused by poliovirus which has three serotypes type 1 is most frequently associated with paralytic disease. Poliovirus replicates in the oropharynx and intestinal tract and is excreted in oral secretions and feces, which can infect others. As a result, more than 90% of unvaccinated individuals will become infected with poliovirus following household exposure to wild-type poliovirus. Since the introduction of the first poliovirus vaccine, there has been a significant reduction in the number of polio cases. Today, polio caused by wild-type poliovirus has been eradicated from the Western Hemisphere with the goal of eradicating it from the world.11... 

The first inactivated poliovirus vaccine was introduced in the 1950s in an injectable formulation, and replaced in the 1960s by a live oral poliovirus vaccine. The oral poliovirus vaccine not only elicits systemic immunogenicity but also a localized immune response in the intestinal tract. Unfortunately, the oral poliovirus vaccine has the risk of vaccine-associated paralytic poliomyelitis occurring in approximately 1 case of every 2.4 million doses distributed. The risk with the first dose of oral poliovirus vaccine is 1 case in 750,000 doses.11... 

The last reported case of indigenous wild-type poliovirus in the United States was in 1979 subsequent cases were all vaccine-associated. In 1997, a transition period to the inactivated poliovirus vaccine was begun to reduce the risk of vac-cine-associated paralytic poliomyelitis. By January 2000, the oral vaccine was no longer recommended for routine use. Currently, the inactivated poliovirus vaccine is recommended for routine use in the United States. The oral poliovirus vaccine is still widely used in some countries where poliovirus eradication has been more difficult. 

Signs and Symptoms Disease is biphasic. Initial symptoms are flu-like and include fever, headache, pain behind the eyes, and a vague feeling of bodily discomfort (malaise). Initial phase does not appear to involve the central nervous system. However, 4-10 days after apparent recover, there is a return of fever with meningoencephalitis or symptoms resembling paralytic poliomyelitis. Convalescence may be prolonged. 

Inoculation of these mice with poliovirus resulted in viral replication in the central nervous system and in the development of a disease analogous to paralytic poliomyelitis. 

Faber, H. K., and Gebhardt, L. D. (1938), Localizations of the virus of poliomyelitis. In the central nervous system during the pre-paralytic period, after intranasal inoculation, J. Exp. Med., 57, 933-954. 

The US 2000 childhood immunization schedule, proposed by the Advisory Committee of Immunization Practices (ACIP), the American Academy of Pediatrics, and the American Academy of Family Physicians, recommended an all-IPV schedule for routine use in the USA, aimed at the elimination of the rare vaccine-associated paralytic poliomyelitis (1). Since 1 January 2000, all children have received four doses of IPV at ages 2 months, 4 months, 6-18 months, and 4-6 years. 

There has been a retrospective cohort study of cases of acute flaccid paralysis reported to the Ministry of Health in Brazil between 1989 and 1995 (24,25). For the first dose of OPV the estimated risk was one case of vaccine-associated paralytic poliomyelitis per 2.39 million doses for total doses of OVP the risk was one case in 13.03 milhon doses. Most of the cases of vaccine-associated... 

Children of parents who do not accept the recommended number of vaccine injections. These children may receive OPV only for the third nr fourth do.se ur both. In such cases, the health care provider should administer OPV unly after discussing the risk uf OPV-associuted paralytic poliomyelitis with parents or caregivers. 

Weibel, R.E. Benor, D.E. Reporting vaccine-associated paralytic poliomyelitis Concordance between the CDC and the National Vaccine Injury Compensation Program. Am. J. Public Health 1996, May, 86 (5), 734-737. 

The routine use of OPV in the United States has been discontinued because OPV is rarely associated with vaccine-associated paralytic poliomyelitis (VAPP) in vaccinees (1 in 6.2 nulhon doses) or... 

Centers for Disease Control and Prevention. Prolonged poliovirus excretion in an immunodeflcient person with vaccine-associated paralytic poliomyelitis. MMWR 1997 46 641-643. 

An analogous example in the civilian context could be made in the case of polio immunizations, where a 1 in 2.4 million chance exists that an oral polio virus vaccine will actually cause the disease. The risk posed by the vaccine is extremely small, but it is real, and yet poliomyelitis hasn t been seen in the Western Hemisphere since 1991. On an individual basis, a case could be made that the chances of acquiring polio, unless one travels abroad or has contact with people from endemic regions, is even less than that of acquiring vaccine-associated paralytic poliomyelitis. But there is no question that continued polio vaccinations are required in the United States, and indeed a global eradication campaign is underway to completely eliminate the virus. 

Acute paralytic poliomyelitis is still endemic in some countries and vaccine-associated poliomyelitis continues to occur (125). After many years of stability, some patients do deteriorate (126). This post-polio syndrome may be characterized by the development of progressive weakness associated with respiratory symptoms among those ventilated during their acute illness (127). Respiratory failure results from thoracic restriction as well as muscle weakness and bulbar involvement (128). Tracheostomy can be avoided with continuous NIV and aggressive mechanical in-exsufflation (128). Retrospective studies of NIV have reported survival rates >90% at five years, making this group the one with the highest benefit (76,129). 

Kidd D, Howard RS, Williams AJ, et al. Late functional deterioration following paralytic poliomyelitis. Q J Med 1997 90 189-196. 

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