WHO alerts to new strains of vaccine-derived polio in southern Nigeria, Lagos

The World Health Organisation (WHO) has alerted to a recent emergence and spread of new strains of vaccine-derived poliovirus type 2 (cVDPV2) in southern Nigeria and, especially Lagos.
WHO disclosed that there is evidence of missed transmission in Nigeria and Somalia, which suggests that the situation continues to deteriorate.
It said the detection of cVDPV2 strains underscores the importance of maintaining high level of routine polio vaccination at all levels to minimise the risk and consequences of poliovirus circulation.
A statement by the Twenty-first International Health Regulations (IHR) Emergency Committee Regarding the International Spread of Poliovirus, released yesterday, noted that the spread of vaccine-derived polio in southern Nigeria was in spite of mass immunisation with Monovalent Oral Poliovirus Type 2 (mOPV2).
Director General of WHO had convened the committee on May 14, 2019 at its headquarters in Geneva, Switzerland with members, advisers which invited member states attended via teleconference, supported by WHO’s secretariat.
The Committee said: “Insufficient coverage with Inactivated Polio Vaccine (IPV) exacerbates the growing vulnerability on the continent to cVDPV2 transmission.
“Early detection of any international spread from the five currently infected countries and prioritized use of mOPV2 is essential to mitigate further depletion of the limited mOPV2 supply.
“Repeatedly, cases have occurred in border districts (in Nigeria, close to Benin, in Democratic Republic (DR) of Congo, close to Angola, in Somalia, close to Ethiopia and in Mozambique, close to Malawi).”
Meanwhile, the committee said the multiple cVDPV2 outbreaks on the continent of Africa are as concerning as the Wild Polio Virus type 1 (WPV1) situation in Asia.
It, however, said despite the significant further increase in WPV1 cases globally in 2019, particularly in Pakistan where 15 cases have already been reported, Nigeria has not detected any case for over two and half years and may be certified WPV free by WHO by early 2020.
The certification, according to WHO would happen after careful assessment of the risk of missed transmission in inaccessible areas of Borno, and other countries in the region where there is lack of confidence in surveillance.
The committee agreed that the risk of international spread of poliovirus remains a Public Health Emergency of International Concern (PHEIC) and endorsed extension of temporary recommendations for another three months.