Eradication Programs
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(Picture from http://www.pbs.org/)

Following the widespread use of poliovirus vaccine in the mid-1950s, the incidence of poliomyelitis declined rapidly in many industrialized countries. In the United States, the number of cases of paralytic poliomyelitis reported annually declined from >20,000 cases in 1952 to <100 cases in the mid-1960s. The last documented indigenous transmission of wild poliovirus in the United States was in1979. In 1985, the member countries of the Pan American Health Organization adopted the goal of eliminating poliomyelitis from the Western Hemisphere by 1990. The strategy to achieve this goal included increasing vaccination coverage; enhancing surveillance for suspected cases (i.e.,surveillance for acute flaccid paralysis); and using supplemental immunization strategies such as national immunization days (NIDs), house-to-house vaccination, and containment activities. Since 1991, when the last wild-virus-associated indigenous case was reported from Peru, no additional cases of poliomyelitis have been confirmed despite intensive surveillance. In September 1994, an international commission certified the Western hemisphere to be free of indigenous wild poliovirus. The commission based its judgment on detailed reports from national certification commissions that had been convened in every country in the region. In 1988, the World Health Assembly (the governing body of the World Health Organization) adopted the goal of global eradication of poliomyelitis by the year 2000. Substantial progress toward meeting this objective has already been achieved in many WHO regions, including East Asia, the Middle East, Southern and Eastern Africa,and Europe. By the end of 1998, almost all polio-endemic countries had conducted NIDs. The number of reported cases of paralytic polio, as well as the number of countries reporting cases, has decreased significantly since the global eradication program began. In 1997, over half of all polio was reported from the Indian subcontinent (the S.E. Asian region of WHO). Polio is still endemic in parts of the Eastern Mediterranean and Africa. While 30 countries worldwide are still considered polio-endemic, intense activities are currently targeted towards interrupting virus transmission in ten remaining priority countries facing particular challenges: 

The final battle to wipe out polio will be fought in these ten global priority countries, where virus transmission has to be stopped as soon as possible in order to reach the global target. Millions of health workers and volunteers, as well as the global polio eradication partnership - led by Rotary International, WHO, UNICEF, and an increasing number of other international partners - are now focusing all their energies towards supporting the efforts of remaining priority countries to eradicate polio.(Pictures from http://www.cdc.gov/)

Why should eradication be successful?
a.  There are no animal reservoirs
b.  The virus is not airborne
c.  There are only three serotypes
d.  Poliovirus entry into cells is very inefficient
e.  There are presently 2 effective vaccines
f.  One of the vaccines (OPV) can be given orally and is inexpensive
g.  Wild type viruses have been eliminated in much of the developed world 

Keys to successful vaccination program in endemic countries:
a.  Public health infrastructure
b.  Community health education
c.  Proper vaccine storage
d.  Vaccine provided at a convenient time and place
e.  Popular support, active participation of community leaders and the community itself 

How should worldwide vaccination proceed?
Vaccinations done in endemic countries with OPV until wild poliovirus circulation is minimal. Afterwards, IPV vaccinations should be used worldwide. Exterminating OPV will minimize the risk of generating harmful poliovirus by mutation and recombination. The use of IPV will lead to an increase in the costs necessary to continue the eradication program. IPV vaccination can be stopped when it is certain that wild poliovirus, OPV, and mutant or recombinant strains are no longer circulating. In addition, measures must have been taken to exclude virus escape from laboratories and vaccine factories. A combination of efforts should be applied, including AFP surveillance, serological tests, and tests of sewage and feces samples to acertain the level of circulating poliovirus. 

Research Topics Important to the Eradication Initiative:

·Characterizing RNA sequences that determine transmissibility and determining the possibility that such sequences develop by genetic drift or recombination. 

·Developing serological tests that are able to detect infected persons in IPV-vaccinated populations. 

The facts that both OPV and IPV induce high levels of immunity and that OPV is relatively inexpensive to develop and distribute,have hampered efforts to create novel vaccines. OPV is highly effective at eliminating wild type poliovirus, and IPV is effective at eliminating vaccine virus reversions that can lead to VAPP. 


AFR = African Region, AMR = American Region, EMR = Eastern Mediterranean Region, EUR = European Region, SEA = South-East Asian Region,
WPR = Western Pacific Region. Click here for specfic countries in each region as defined by the World Health Organization.
(Statistics taken from WHO:http://www.who.int/ )

(Picture taken from http://www.cdc.gov/epo/mmwr/preview/mmwrhtml/00053047.htm)

Additional Links Relevant to Eradication Programs:

1.For Current List of Year 2000 Global National Immunication Days.

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