Polio eradication methods, lessons from Nigeria<\/p>\n
Andrio Adiwibowo, Jakarta<\/p>\n
During the past several weeks, Indonesia has been shocked by
\nthe return of the polio virus to Java. The small initial outbreak
\nthat was centered in the Sukabumi region in West Java has been
\nreported to have spread to areas nearby. Many researchers are
\nconsiderably concerned about the reoccurrence of polio in
\nIndonesia, on top of the other numerous deadly diseases that the
\ncountry is hit with almost every year, including dengue fever,
\navian flu, and SARS. For a little more than a decade, Indonesia
\nhad thought it had eradicated polio successfully.<\/p>\n
How did this illness, caused by the poliovirus, reoccur in
\nIndonesia again? This issue has challenged researchers to address
\nthe following questions. First, is it possible that within
\nseveral decades the virus has mutated and into a new type of
\nvirus, which has high resistance against the available cures or
\nperhaps the old virus type has been replaced by a wild polio
\nvirus that has not been detected yet?<\/p>\n
Meanwhile, certain local communities living in rural areas are
\nnot as concerned with sanitation issues as their city
\ncounterparts, or do not have access to proper hygienic
\nfacilities, and this could promote the rapid spread of the virus.
\nVillage people tend to defecate in the waterways, while they also
\nuse the same canals or rivers for household purposes; including
\nwater for drinking and washing. Human feces can contain millions
\nof viruses. It is also possible that the human resistance and
\nantibody systems in the present generation are less strong than
\nin previous generations. As a result, people become more
\nvulnerable to the virus.<\/p>\n
The prevention -- the polio vaccination -- plays a vital role
\nin promoting the success of polio eradication. However, we should
\nbe concerned about the possibility that a failure to vaccinate or
\neven a vaccine failure has taken place. There could also be
\nproblems with how the vaccine was administered to patients --
\nwere they given the right dose or not?<\/p>\n
The presence of a mutated virus or one of an undefined new
\ntype such as a wild poliovirus strain is one of the significant
\nobstacles to polio eradication around the world. Many researchers
\nhave found new wild polioviruses across the Africa and Asian
\ncontinents. For example, a new wild virus that has significantly
\ndifferent genetic material than the common Asian polio virus has
\nbeen found in a particular area in the Mekong River near Vietnam
\nand Cambodia.<\/p>\n
Recently, it was assumed that the polio outbreaks in Indonesia
\nwere caused by a wild virus that originated from the African
\ncountry of Nigeria. That country, along with India and Pakistan,
\nis known to be a poliovirus reservoir. Last year, a strain of the
\nvirus was found firstly in Kano State, Northern Nigeria. The
\ninfection spread rapidly into neighboring countries, such as
\nBurkina Faso, Chad, Ghana, and Togo.<\/p>\n
The return of polio in Nigeria surprised the global health
\nauthorities, who had earlier categorized the eradication campaign
\nthere as remarkably successful. According to the latest research,
\nthe most common cause for the persistence of polio disease in
\ndeveloping countries has been the failure of routine immunization
\nprograms to provide the correct dose of the poliovirus vaccine to
\na high proportion of the countries' infants; not the presence of
\nany new wild polio virus. This vaccination error was identified
\nin Nigeria. The leaders of public health facilities in the
\ncountry had failed to provide children the right dosage, which is
\n10 doses of the vaccine per infant.<\/p>\n
However, a more worrisome pattern of disease can be attributed
\nmore to vaccine failure than a failure to vaccinate. The Oral
\nPolioviruses Vaccine (OPV) has been found to provide less
\neffective prevention than the Inactivated Poliovirus Vaccine
\n(IPV). Today, national leaders of public health have no
\nopportunity to make an informed choice between the OPV and the
\ninactivated poliovirus vaccine (IPV). In fact, they tend to use
\nthe OPV exclusively. Unfortunately, the routine use of OPV could
\nmean patients risk the vaccine-associated paralytic poliomyelitis
\n(VAPP) disease.<\/p>\n
While it is believed that discontinuing OPV activities could
\nlessen the threat of VAPP, any delay in the changeover to the IPV
\ncould still yield negative outcomes. Halting an OPV program will
\nincrease the risk of vaccine-derived polioviruses (cVDPV)
\nemerging that acquire wild virus-like properties and may cause
\nfurther outbreaks of polio.<\/p>\n
The IPV is currently the best vaccine to supersede the OPV.
\nHowever, at the moment the IPV option is restricted to developed
\ncountries. The price of the drug, which is too costly for most
\nThird World nations, and their local officials' lack of large-
\nscale field experience in administering the vaccine -- are the
\ntwo major barriers to its use.<\/p>\n
Polio eradication strategies should emphasize scientific
\ninvestigations that focus more on the virus inventory, isolation,
\nand identification in order to find new wild polioviruses.
\nFurthermore, this research must be accompanied by extensive
\nstudies that yield effective and affordable vaccines.<\/p>\n
The world demands a vaccine that can moderate the threats of
\nVaccine-Associated Paralytic Poliomyelitis and Vaccine-Derived
\nPolioviruses, and IPV is certainly the answer. However, with the
\nthreat of new mutations, the administration of IPV alone will not
\nbe sufficient to the achieve global eradication of wild
\npoliovirus transmissions, especially in developing countries.<\/p>\n
The first step is to improve the manufacturing capacities in
\nthe developing world so that these countries can produce the IPV
\nat a low cost. The next aggressive approach is a policy shift to
\npromote the use of IPV as the exclusive vaccine during national
\nimmunization campaigns.<\/p>\n
Hopefully, the decision-makers in public health here can learn
\na valuable experience from Nigeria and make the right decision
\nresulting in a sustainable polio eradication plan.<\/p>\n
The writer is a researcher in the Public Health and Virology
\nDepartment at the University of Indonesia, Jakarta. He can be
\nreached on andrio7897@yahoo.com.<\/p>",
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