Polio: What Happens to a Vaccine-Preventable Disease When Vaccination Is Prevented?

Polio is a highly infectious disease that mainly affects children under age five and leads to irreversible paralysis in about one of every 200 cases. The first polio vaccine was developed in 1952 by Jonas Salk. Today, there are two forms of the vaccine: inactivated polio vaccine (IPV) and oral polio vaccine (OPV). OPV can be administered by anyone, including volunteers, and can cost as little as 11 U.S. cents. Although polio used to be a global threat, its prevalence has been reduced by over 99% since formation of the Global Polio Eradication Initiative in 1988. However, despite the existence of vaccines, polio is still endemic in three countries: Afghanistan, Nigeria, and Pakistan. Poor sanitation—including lack of access to toilets and safe drinking water—is often cited as a factor that facilitates the spread of polio because the virus is transmitted through the fecal-oral route. However, another major obstacle to polio eradication is the opposition to vaccination.

Vaccination may be opposed for a variety of reasons, including religious reasons, mistrust, and misconceptions about what the vaccines do. For example, in 2003-2004 in Nigeria, rumors were spread that the polio vaccine was sterilizing children as a form of population control and contained HIV. In Pakistan, similar rumors have surfaced in addition to some claims that the vaccines contain pork (which, for the country’s large Muslim population, is non-halal). In addition, in poor regions of these countries, the lack of basic necessities like water and electricity has caused communities to question government spending on polio vaccines. Other times, vaccination may be prevented by social or political unrest that make it difficult and unsafe for vaccination campaigns to take place. The latter reason has been the case in both Nigeria and the Federally Administered Tribal Areas of Pakistan.

Turmoil caused by the Boko Haram insurgency has impeded polio eradication efforts in the northern states of Nigeria, where polio transmission is ongoing and vaccination campaigns are most needed. Boko Haram has become well known by the international community in recent months following the kidnapping of hundreds of schoolgirls in April this year. The name “Boko Haram” means “Western education is forbidden,” and the group also opposes Western-sponsored polio vaccination campaigns. One notable attack on healthcare workers in Nigeria occurred in February 2013, when nine women were targeted by gunmen for working on a polio vaccination campaign. Nigeria has had five polio cases this year in the northern states of Kano and Yobe, the most recent of which was reported in Kano state in the past week. Aid workers have been implementing a “hit and run” strategy to vaccinate unsafe areas by sending mobile units in and out as quickly as possible.

In Pakistan, polio cases are heavily concentrated in the Federally Administered Tribal Areas (FATA), where militancy and unrest are also prevalent. This June, a Pakistani Taliban commander banned polio vaccines in North Waziristan, a region in FATA responsible for 63% of the country’s cases this year. The Pakistani Taliban and connected militant groups oppose vaccines in part because the U.S. used a polio vaccination campaign as a cover to facilitate the search for Osama bin Laden in 2011. That operation outraged many in the public health community who feared the deception would increase the danger to polio workers (for more information, see http://blogs.plos.org/speakingofmedicine/2011/09/12/failed-vaccine-campaigns-are-a-global-issue/). On July 7, the Afghan Taliban also banned polio vaccinations in a southern province of Afghanistan. As in Nigeria, polio workers have been targeted for carrying out vaccination campaigns. Eleven people were killed in Khyber Agency on March 1, 2014 when a roadside bomb hit vans carrying polio vaccination workers. Later in March, a Pakistani polio worker in Peshawar was kidnapped and killed—supposedly because of her work. Despite the dangers and opposition that polio workers have faced, about 2.5 million Pakistani children were vaccinated in Khyber-Pakhtunkhwa and tribal regions last month as part of a three-month campaign. This initiative was launched by the UAE Pakistan Assistance Programme (UAE PAP) and was effective because it was led by the UAE in cooperation with Pakistan’s army and ministry of health.

Pakistan has had 94 polio cases this year—more than any other country in 2014. According to a Global Polio Eradication Initiative update as of July 15, Afghanistan is next with eight cases, followed by Equatorial Guinea and Nigeria with five each. Somalia has had four cases, Cameroon has had three, Iraq has had two, and Syria and Ethiopia have had one case each. Wild poliovirus discovered in an environmental sample in São Paolo, Brazil was found to be genetically similar to the strain in Equatorial Guinea.

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