A health worker immunising a child in Kano, northwest Nigeria, in April 2017. | Photo Credit: PIUS UTOMI EKPEI
On August 21 this year, Nigeria crossed an important milestone in the eradication of polio when it successfully completed three successive years without a single case of wild poliovirus. A country is said to have eradicated polio when no fresh case of wild poliovirus is reported for three successive years.
The last case of type 1 wild poliovirus in Nigeria was reported in August 2016 in Borno State, in the country’s insurgency-hit northeast. The official announcement by the World Health Organization (WHO) is expected by early next year.
With Nigeria almost winning the war against the wild poliovirus, the endgame is getting closer. Today, wild poliovirus is endemic only in two countries — Pakistan and Afghanistan. Global eradication will depend on stopping the disease in these two countries. But as long as polio exists in any part of the world, children are at threat everywhere.
Just as it appeared to be easy to snuff out the virus in these two Asian countries, there has been a spike this year. As on September 11 this year, there have been 16 and 62 wild poliovirus cases reported in Afghanistan and Pakistan respectively. Compared to 2018, the number of cases in Afghanistan reduced while it increased manifold in Pakistan.
After being removed from the WHO’s list of ‘polio endemic countries’ in September 2015, Nigeria came close to eliminating polio the very next year. However, it faced a setback in July-August 2016 when three fresh cases were reported.
The wild virus strain that caused the fresh cases was found to be linked to the virus detected in 2011 in Borno, indicating that the strain was still present in the environment. This did not come as a surprise as health-care workers had not been able to access as much as 60% of settlements in Borno due to the decade-long insurgency in northeast Nigeria.
As a result, about 5,00,000 children in the State were deprived of health services by 2016.
Like the Democratic Republic of Congo during the latest outbreak of Ebola, Nigeria had to rely on security personnel to escort health workers to Borno. But certain areas were out of bounds for health-care workers and access was limited to only military personnel. Nigeria came up with a unique strategy to reach out to children by training the military personnel to double up as vaccinators.
These strategies have borne fruits. Health workers, accompanied by security personnel, were able to immunise 80% of children with three doses of the vaccine containing only type 1 and type 3 polio viruses. Military personnel by themselves were able to reach 26%.
However, the success of the two strategies notwithstanding, about 60,000 children are yet to be vaccinated in the insurgent-held areas, according to a July 2019 paper; the true status of wild poliovirus in these children remains unknown.
And even as wild poliovirus appears to be tamed in Nigeria, as on August 28, 2019, the weakened type 2 virus used in oral polio vaccine had turned virulent and caused 16 cases of paralysis, down from 34 last year. Though vaccine-derived polio cases will not come in the way of Nigeria being certified as ‘polio-free’ by the WHO, multiple outbreaks of such kind are concerning, particularly the emergence of new strains in areas where oral vaccine containing only type 2 was used.
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