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Global polio eradication requires domestic, international support

NEW YORK — During his keynote address at the 2014 Infectious Diseases in Children Symposium, Walter A. Orenstein, MD, praised the significant progress in global eradication of polio, but noted that reservoirs of the disease remain, indicating a need for increased efforts worldwide.

From 2009 to 2013, the number of confirmed cases of wild poliovirus type 1 decreased from 482 to 416, while confirmed cases of wild poliovirus type 3 decreased from 1, 122 to zero. In 2009, there were 1,256 confirmed cases of wild poliovirus in endemic countries, compared with 272 in 2014.

Walter A. Orenstein

India and the WHO Southeast Asian Region have recently been declared polio-free, the number of confirmed cases has been reduced by 99.9% compared with when eradication efforts began in 1988 and geographic spread is limited, according to Orenstein.

Though significant progress has been made, incidence has increased in recent years. There were 223 cases of wild poliovirus reported in 8 countries in 2012 and 416 cases reported in 13 countries in 2013, according to data published in the Journal of Infectious Diseases.

To achieve global eradication of polio, the Polio Eradication Strategy calls for routine immunization, national immunization days when all children aged younger than 5 years are vaccinated, followed by careful surveillance and mop-up campaigns.

Disease surveillance, routine coverage and coverage monitoring via finger marking and house marking are essential to polio eradication, according to Orenstein.

Barriers of global polio eradication include insecurity, political commitment and immunization system quality, surveillance, travel regulation enforcement, financial support, partnerships and advocacy.

“The most significant problem is human behavioral science — if people are killing vaccinators because of mistrust, how do you administer a vaccine to children in need of protection against polio?” Orenstein said. “There are efforts to work with Islamic scholars and religious authorities because the majority of polio is now focused in Islamic areas. There are efforts to work with security specialists and others to try and overcome this.”

Even though risk for poliovirus in developed countries is low, infection and transmission is possible, especially in areas of under-immunized children, Orenstein said.

Diagnosing polio can be difficult, Orenstein noted, as the patient may not have a travel history to a polio endemic or epidemic country; additionally, infection can be subclinical and may not present as a typical paralytic illness.

“Suspect polio in someone with a clinically compatible case as we are reliant on your suspicion,” Orenstein said. “If you have a clinically compatible case, call your health department immediately. Begin to collect data and stool samples. Serology is not very helpful usually in polio, but it is something to consider to do. Remember that because there is so much silent transmission you may not get any travel history. Travel history can help but it should not rule out suspicion if you have a clinically compatible case.”

Orenstein reiterated that the US immunization schedule calls for 4 doses of inactivated polio vaccine to be administered at 2, 4, 6 and 18 months of age with a booster dose at 4 to 6 years.

To prevent infection and transmission domestically and globally, developed countries should:

• Ensure immunization of those travelling to polio-affected areas;
• Test for polioviruses among those with acute flaccid paralysis;
• Advocate for introduction of inactivated polio vaccine in developing countries; and
• Provide financial support for the overall polio initiative.

“The most important issue is that as long as there is polio anywhere, there is risk for polio everywhere,” Orenstein said. “I think we all have a role in trying to finalize eradication to make polio the second disease to ever be eradicated, a gift from our generation to every future generation.”

For more information:

Orenstein WA. “Polio eradication: The endgame strategy.” Presented at: IDC NY 2014; November 22-23, 2014; New York.

Disclosure: Orenstein reports no relevant financial disclosures.