SEATTLE — Two new cases of polio in Nigeria, in the northeastern state of Borno specifically, have set off a massive vaccination drive to prevent the spread of the disease across Africa.
Over the coming months, the Nigerian health ministry and World Health Organization (WHO) plan to vaccinate about five million children in several rounds across the rest of northeast Nigeria near Lake Chad.
The campaign will extend to parts of Chad, Cameroon and the Central African Republic, according to the WHO. “The overriding priority now is to rapidly immunize all children around the affected area and ensure that no other children succumb to this terrible disease,” Dr. Matshidiso Moeti, WHO Regional Director for Africa, said in a release.
The discovery of a four-year-old girl and 12-month-old boy paralyzed by poliovirus in Borno has dismayed health authorities and been a major setback to global efforts to eradicate polio. Prior to the new cases, Pakistan and Afghanistan were the only other countries that were reporting an ongoing transmission of the virus.
Health officials had been ready to declare Africa polio-free, after no new cases of the disease were detected in the continent since 2014. The WHO recognizes a region as polio-free after three years with no confirmed cases.
But with the latest discoveries, the WHO now believes that polio in Nigeria has been silently circulating.
According to the WHO release, genetic sequencing of the viruses indicates that the recent cases are linked to a wild strain of polio detected in two different towns in Borno in 2011.
The fact that just about one poliovirus infection in 200 results in paralysis further suggests that other people in the area have the disease.
The low-level transmission of polio is not surprising, the WHO has noted. Borno has been a military stronghold of the terrorist group, Boko Haram, which has publicly denounced vaccination campaigns as a Western plot and made much of the state off limits to polio immunizers.
“The security and access to immunization to the population is not guaranteed [in Borno]as it is in other parts of the country,” Dr. Michel Zaffran, the WHO’s director of polio eradication, said in a Facebook Live discussion. “And therefore, the coverage […] is not as high as would be desirable to ensure interruption of transmission.”
According to a statement by Nigeria’s health ministry, the latest detections only came after a military offensive by the Nigerian Army pushed Boko Haram out of several areas in Borno.
Nigeria has had difficulty containing polio in the past.
In 2003, several northern Nigerian states halted polio vaccinations amid rumors that the vaccine was contaminated and would harm children. The rejection of the treatment significantly lowered rates of vaccination.
By 2006, Nigeria had the greatest number of confirmed cases of polio in the world. Although the prevalence of polio in Nigeria decreased over the next six years, the country still accounted for over half of all world cases in 2012, according to the WHO.
In recent years, polio in Nigeria was under control thanks to a renewed commitment by multiple levels of the Nigerian government and religious leaders to eradicate the virus. Evidence by the WHO that the vaccine was safe as well as billions of dollars in aid donations helped spark the response.
But health authorities will face more challenges to contain the latest outbreak.
Several areas of Borno are difficult to access because of security concerns and the threat of raids by Boko Haram. To overcome this, Zaffran said that WHO will provide vaccines to local medical workers from Borno who can more easily travel to hard-to-reach locations and vaccinate children.
Zaffran also told Time that health teams will have to be ready to quickly move into less secure areas when there are openings.
Another obstacle involves migratory people. According to a report by the New York Times, many people who were displaced by violence by Boko Haram are now beginning to return home. Nomadic Fulani people and herders are also constantly crossing borders and searching for water. Such populations that are on the move are especially hard to vaccinate.
In order to treat people that travel around, health officials must reach them as they move in and out of areas. Health camps, which polio vaccination teams have relied on in the past, can serve as temporary clinics and shelters for migrants as they receive the vaccine.
– Sam Turken