There are growing concerns over the outbreak of Vaccine Derived Poliovirus type 2 (cVDPV2) in 13 states and the Federal Capital Territory (FCT).
The virus is contracted as a result of many factors, including refusing to take the shots or not completing polio vaccines.
While the Wild Polio Virus (WPV) is the most common form of poliovirus, circulating vaccine-derived poliovirus or cVDPV is another form of polio that can spread within communities which Nigeria is currently experiencing.
Medical experts say the outbreak is a public health concern and warned that it is a threat to Nigeria’s wild polio virus-free status.
The outbreak of cVDPV2 came to the fore barely one year after Nigeria was certified wild polio virus-free by Africa Regional Certification Commission (ARCC).
Before the certification, Nigeria was the only wild polio-endemic country in Africa.
The last case of wild poliovirus was detected in Nigeria in 2016. Since 1996, polio eradication efforts had prevented up to 1.8 million children from crippling life-long paralysis and saved approximately 180, 000 lives, according to the World Health Organisation (WHO).
The recent surge in Nigeria
The Executive Director of the National Primary Healthcare Development Agency (NPHCDA), Dr Faisal Shuaib, had on Monday, July 5, announced that the country was witnessing a cVDPV2 outbreak in Abia, Bayelsa, Borno, Delta, Federal Capital Territory (FCT), Jigawa, Kano, Kebbi, Lagos, Niger, Rivers, Sokoto, Yobe and Zamfara states.
“As we are all aware, Nigeria has been certified WPV free by the Africa Regional Certification Commission (ARCC). However, there are cases of cVDPV2 in some states, hence the need for us as a country to jealously guard our WPV-Free status and stop the cVDPV2 transmission in our communities,” he said.
According to him, the agency had conducted four Outbreak Responses (OBRs) using the Novelle Oral Polio Vaccine, which was a preferred choice as it does not seed the virus.
He added that “sub-optimal performance has been recorded in all the states due to the high number of missed children during the exercise. This poor quality will affect how we are able to bring this outbreak under control.”
Dr Shuaib said that donor funding for polio had reduced drastically and called on traditional rulers to continue to draw the attention of political leaders on the need to continue to fund polio outbreak response campaigns.
‘We risk losing our wild polio-free status’
Prof. Oyewale Tomori, a renowned virologist and past president of the Nigeria Academy of Science said the current outbreak of cVDPV2 was of great concern and evidence of the poor level of immunisation of children especially newborns.
He said the more severe implication of the drop in the level of immunity is that with wild poliovirus still circulating around the world, importation of the wild strain will spread like wildfire among the poorly immunised children and Nigeria could lose her wild polio-free status.
He said,” Put simply, unless we take remedial action urgently, not only are we in the danger of continuous circulation of vaccine-derived poliovirus, which will continue to paralyse our under-protected children, we are in addition on the way to losing our wild polio-free status should the wild poliovirus be imported and spread in Nigeria.
“Years of efforts to interrupt the transmission of wild poliovirus will be wasted. Before we reverse our success, we must urgently revive and strengthen our routine immunization activities,” he said.
How wild poliovirus differs from current outbreak
Prof. Tomori said the Wild Polio Virus (WPV) is the ‘normal’ virus that causes the paralysis associated with polio.
“It has been in existence since ancient times with records of the disease in the time of Egyptian Pharaohs. On the other hand and as the name suggests, the circulating Vaccine-Derived Poliovirus (cVDPV) is derived from the vaccine”.
“There are two types of polio vaccines derived from the wild virus. One type is the killed or inactivated polio vaccine. When inoculated into a child, there is no virus multiplication but the body develops immunity and protection against future infection by the wild virus.
“Another type is the attenuated or weakened wild poliovirus, which has the capability to multiply in the body but does not cause polio disease especially in children who are adequately immunised and protected.
“However, in a child that is under immunised, the vaccine virus will also multiply and causes polio disease because of the low level of immunity in an inadequately vaccinated child. When such a virus is transmitted from child to child or within a community, it is called a circulating Vaccine Derived Polio Virus (cVDPV),” he said.
Roles of insurgency, COVID-19 in current outbreak
Prof Sunday Omilabu, a virologist with the Lagos University Teaching Hospital (LUTH), said insurgency particularly in the North East, unrest in other parts of the country and the COVID-19 lockdown prevented many children from assessing polio vaccination.
He said the disruption had created a gap in immunization coverage which led to the spread of the cVDPV2 in communities.
According to him, healthcare workers were unwilling to give children vaccines because they were afraid they could get killed or kidnapped like their colleagues, adding that with this, there were possibilities that children would come down with vaccine-derived strain.
“The situation now is not a very good one. We expected this kind of thing to happen after a while. When people are not covered with immunization, sooner or later, there will be an outbreak.
“Truly the country was certified polio-free after three years, but now, these are not wild range; they are only vaccine-derived. They (children) did not get the vaccine when they ought to,” he said.
He said to avoid spread, there was an urgent need to reach out and immunise all children in the areas where the vaccine variant has been discovered.
“That is the only solution. This is because the children’s immune system is not strong enough to fight against the paralysis strain,” he said.
He added that it was important to start giving them vaccines before it spreads to all the states.
Tanimola Akande, a professor of public health at the University of Ilorin said the cVDPV2 outbreak was a public health concern because the desired thing was for no one to be infected with wild poliovirus and the cVDPV2.
Prof. Akande, who is also an epidemiologist and former National Chairman of the Association of Public Health Physicians of Nigeria said addressing the cause of the outbreaks remained the only option to tackling the disease.
He said the outbreaks were driven by several factors, including low-quality polio outbreak response, declining immunity in young children to the type 2 virus and insufficient routine immunization coverage.
He said in 2020, the COVID-19 pandemic led to a pause in house-to-house polio campaigns which further hindered efforts to stop transmission across affected countries.
According to him, all these factors must be addressed to stop the outbreak.
“The use of Novel Oral Polio Vaccine (nOPV2) could be a critical tool for stopping cVDPV2, but the best protection against all types of polio remains ensuring that all children are vaccinated in routine and supplementary immunisation campaigns and maintaining strong disease surveillance,” he said.
Status of states affected by the virus
The Executive Secretary of Yobe State Primary Health Care Management Board, Dr Babagana Kundi Machina said Yobe has recorded cVDPV2.
The Rivers State Commissioner of Health, Professor Kingsley Chike did not answer several telephone calls and text messages put across to him on the number of persons affected by the outbreak in the state but a source at the state Primary Health Management Board who craved anonymity said that they were aware of the enlistment of the state as one of those affected by the virus.
While the Niger State Government said there was no outbreak of cVDPV2 in the state as mentioned by the NPHCDA, the FCT health authorities said there was a case recorded in Suleja, which is in Niger State but that none was recorded in the FCT.
The state’s Director of Public Health, Dr Ibrahim Idris said no case was recorded so far but that they were on the lookout.
He added that immunisation was ongoing across the state but insisted that the state has not recorded any new cases.
Dr Iwot Ndaeyo, the acting Executive Secretary of FCT Primary Health Care Board said no case has been confirmed for FCT up to this moment.
He said the address by the NPHCDA during a meeting with traditional rulers was misquoted as affirmed by the officer who represented the executive director.
“Yes, the circulating virus has been confirmed in Niger State when Gwagwalada Area Council, sharing boundaries with the affected local government area in Niger had to participate and conduct the 2-rounds outbreak response to forestall spread to the area. These were done in March and April this year,” Ndaeyo said.
By Ojoma Akor (Abuja), Risikat Ramoni (Lagos), Ibrahim B. Saleh (Damaturu), Victor Edozie (Port Harcourt), Romoke W. Ahmad (Minna) & Hamisu K. Matazu