Authorities in northern Nigeria’s Kano State have confirmed the detection of four new variants of the poliovirus, raising fears of a possible resurgence of the disease nearly five years after the country was declared free of wild polio.
The development was announced by the Director General of the Kano State Primary Health Care Management Board (KSPHCMB), Professor Salisu Ahmad, during a town hall meeting to mark World Polio Day on Wednesday.
Ahmad, speaking through the board’s Director of Disease Control, said the new cases highlight the risks of complacency in routine immunisation and warned that the progress achieved in eradicating polio could be reversed if vaccination efforts decline.
Between 2013 and 2015, Kano was the epicentre of polio transmission in Nigeria before intensive vaccination and surveillance campaigns eliminated the virus, Ahmad said. “The fight is not yet over,” he added, noting that one of the recently detected cases is still undergoing laboratory confirmation.
Kano State Immunisation Officer, Hajia Saadatu Ibrahim, said two of the new variants were found in children from rural communities, while the other two were detected in contaminated water samples collected from urban areas.
“Environmental sanitation alone cannot stop vaccine-preventable diseases,” Ibrahim said. “We must continue to ensure that every child is vaccinated.”
She recalled that in 1988 there were about 350,000 global cases of polio, but sustained immunisation campaigns reduced the number dramatically, leading to eradication in most parts of the world. Nigeria, declared free of wild poliovirus by the World Health Organization in August 2020, was among the last countries to eliminate the disease.
Despite that milestone, the country continues to face outbreaks of circulating vaccine-derived poliovirus type 2 (cVDPV2), a rare strain that can re-emerge in under-immunised communities when the weakened vaccine virus mutates.
Kano, Borno and Sokoto states have reported sporadic detections of such strains in recent years, largely linked to low vaccination coverage and environmental contamination.
Health officials say the newly discovered variants in Kano underscore the need for sustained surveillance, public awareness and renewed immunisation campaigns to prevent a resurgence of the virus.