Medicine

Nigerian states keep pressure on vaccine-derived polio

Abuja, 23 October, 2020 – On 25 August 2020, health workers and survivors in Nigeria celebrated the end of wild poliovirus in the country. They joined the entire Africa region in a joyous online event in August to mark the continent’s wild polio-free status, a historic moment in the global fight against the disease.

But despite the victory, the fight against other forms of the poliovirus is not over. Cases of vaccine-derived polio caused by low and infrequent immunization are still being recorded in the West African country, including in major states like Lagos and Sokoto, highlighting the need for continued vigilance to nip a possible outbreak in the bud.

Following the discovery of a case of Circulating vaccine-derived poliovirus (cVDPV) in the northwestern agrarian state of Sokoto in early 2020, health authorities there are unrelenting in their actions to vaccinate all children under five years, the age at which the vaccine-derived polio disease is likely to set in.

“We continue to do this work because it is important for the children’s future,” says 26-year-old Amina Ibrahim, a vaccinator in Sokoto who works in communities despite the COVID-19 pandemic. “What we do is make sure we wash our hands, wear our face masks and maintain two-meters physical distance as we go from house to house.”

First discovered in Madagascar in 2001, circulating vaccine-derived polio often occurs when a child who has been vaccinated with the oral polio vaccine (OPV) and who is in an area with poor sanitation passes stool or urine. The weakened live virus present in the urine or stool could find its way into the systems of other under-immunized kids through contaminated water or food and mutate, becoming infectious and causing life-long paralysis and in some cases, death.

Circulating vaccine-derived polio poses risks to children everywhere because of its highly infectious nature. Nigeria has been experiencing outbreaks since 2008. One case from an AFP was found in Sokoto in 2020 and last year, the state recorded 14 cases. It is worthy to note that five healthy children were found with the virus during investigation of the current case in Sokoto. The disease is fought in the same way wild polio is: with vaccines that provide the most important protection for children.

To boost immunity against type 2 polio virus, Sokoto state authorities are pushing a massive statewide inactivated polio vaccine (IPV) vaccination campaign targeting about 1.5 million children. Across the state, children are feeling the tiny pinch of a needle that will help protect them for life.

As with wild poliovirus in Nigeria, vaccine-derived polio disease is warded off with a combination of immunization activities, including the use of IPV. The World Health Organization (WHO) recommends routine vaccination with IPV for children below one year old, to prevent risks of polio virus infection. WHO has issued further interim guidance to countries to prepare for the introduction of a second dose IPV in the routine immunization programme. Nigeria has submitted a proposal for support to Gavi in this regard.

Sokoto State health authorities are also intensifying surveillance with the help of community informants to identify and isolate possible cases of vaccine-derived polio disease in the various local government areas.

Supported substantially by WHO, health officers regularly monitor the environment, examining sewer samples in at-risk communities to detect the virus, a method that has proved useful in finding and isolating wild poliovirus cases in the past years.

The surveillance and vaccination efforts are crucial for Sokoto and her 5.3 million population of mostly farmers and cattle herders. The state’s geography makes it an easy target for infections. Situated on the Nigerian border with Niger Republic (which recorded three cases of vaccine-derived polio in October 2020), Sokoto is additionally vulnerable to polio cases that could be imported from other countries. The borders in the West African region are widely known to be porous and polioviruses are themselves highly infectious. In 2008, cases of wild polio spread from Nigeria to several countries including as far as Yemen.

The thoughts of life-time paralysis have made Sokoto parents especially eager to see their kids protected with vaccines. While years ago, parents saw many cases of children affected by polio growing up, the difference is clear now, with fewer children having to go through the pain of paralysis. Nigeria’s polio success also boosted confidence in vaccines, a significant feat in a population that is often wary of medical services seen as foreign.

“I no longer have fear in attending gatherings because my children are now protected from polio,” says Rabi Isyaku, a Sokoto resident whose child was recently vaccinated.

But despite the vaccination push, health workers say they face hurdles in reaching some populations, meaning that vaccination coverage in Sokoto is only moderate. For instance, Penta3 coverage for Sokoto is very sup-optimal at 17.9% (SMART Survey 2018) and only 7.2% (NDHS, 2018).

Parts of the state are insecure due to activities of armed groups, and rumours around vaccines are rife, with one rumour saying they cause infertility in children. It is also challenging to reach nomadic cattle-herding groups who make up a significant population in Nigeria’s north.

Crucially, because of inadequate education, many do not believe in the need to be vaccinated after the wild poliovirus has been declared eradicated and are shunning ongoing vaccinations against both wild and vaccine-derived polio.

These factors have resulted in the state recording 8 outbreaks of vaccine-derived polio between 2019 and 2020 alone. Authorities declared a state of emergency on routine immunization in 2017, created state and local emergency routine immunization coordination centers, and directed more state resources towards delivering vaccines.

“There has been a resurgence of vaccine-derived poliovirus over the years because there’s a significant proportion of under-immunized children,” says Dr Habibu Yahaya, WHO State coordinator for Sokoto. “WHO will continue to support the state with experienced personnel in conducting effective immunization drives particularly in the outbreak areas. Currently, the state is implementing vaccination campaigns in all the 23 LGAs to shore up the population immunity, and we are hopeful because we’ve seen the same response successfully deployed to control outbreaks in Jigawa, Kaduna and Borno states in 2019.” Dr Habibu says the outbreak areas are Sokoto North, Sokoto South, Dange Shuni, Tureta, Rabah and Wurno local government areas.

Despite the challenges, health workers continue to deliver vaccines—and hop—door-to-door, and help parents understand the benefits of vaccines. Nomad trails are tracked with geo-information mapping systems so that vaccinators always know where families are. Once vaccinated, migrant families get a yellow card for easy identification. In communities with poor health infrastructure, state authorities and WHO are supplying drugs for minor ailments to build trust. And there is a productive collaboration between security agencies and local security groups that is helping health workers deliver vaccines safely to conflict-affected communities.

Health authorities are also employing the wisdom of highly revered community and religious leaders, including the Sultan of Sokoto, Alhaji Muhammad Sa’ad Abubakar III, who help quell the myths surrounding vaccines. “We always tell parents to let the vaccinators do their work,” says Aminu Ibrahim, 35, a youth leader in Dange Shuni area. “Our leader, the Sultan of Sokoto immunized children himself, so people now appreciate it more.” Religious sermons and advocacy have helped drive higher numbers of vaccinated children, leaders say, although community members who are also worried about other diseases like malaria seek more incentives from authorities, such as mosquito nets. “We want a society of healthy mothers and children,” added the Sarkin Fulani, Alhaji Nasiru Muhammad.

State authorities acknowledge these gaps and say they are working to do more. “We will leverage the wild poliovirus eradication gains and we will develop strategies towards improving our immunisation coverage,” says the Executive Secretary of Sokoto State Primary Health Care Development Agency, Mr Adamu Abdullahi Romo. “We have already reached a substantial percentage of the population, and with time, people will start to see the results.”

Support for Polio eradication to Nigeria through WHO, is made possible by funding from the Bill & Melinda Gates Foundation, Department for International Development (DFID – UK), European Union, Gavi, the Vaccine Alliance, Government of Germany through KfW Bank, Global Affairs Canada, United States Agency for International Development (USAID), Community Chest Korea, KOFIH (Korea), Rotary International and the World Bank.

 

Source: World Health Organization