Despite stubborn presence in a handful of countries, experts are hopeful that the world might become free of polio by the end of the year.
Polio virus travels in faecal material. It multiplies in the intestine, from where it can invade the nervous system and can cause paralysis. The highly infectious childhood disease was once prevalent throughout the world but has been eradicated in most countries thanks to vaccination, says a report published by The Telegraph.
Pakistan, Afghanistan and Nigeria are the only three countries with ongoing wild poliovirus transmission. According to the Global Polio Eradication Initiative, there have been eight cases of polio in Afghanistan and Pakistan so far this year, compared to five at the same point the year before. In a press briefing to give an update on polio eradication efforts, Michel Zaffran, director of polio eradication at the World Health Organization, said he was hopeful that the disease could be eradicated by the end of this year or next.
“We are closer than we have ever been before to wiping out this virus,” he said. “The next few months will tell us if we may be able to finish the job this year as this is the time when the virus is circulating.”
He added, however, that “we may need another year.”
In Nigeria, there have been no polio cases since 2016. Still, WHO is concerned about Borno state in the north of the country where violence and unrest have meant that polio immunisation campaigns have been abandoned. “While this is promising, we are worried that the very low immunisation coverage rates [in Borno] are making it possible the virus is circulating without being detected,” said Zaffran.
According to him, Pakistan and Afghanistan are putting huge efforts into eradication and introducing innovative practices such as immunising children at bus stops and border crossings. But in certain parts of Afghanistan, such as Kandahar, parents have refused to have their children vaccinated, he said. Vaccination teams have also been unable to reach some parts of the country because of unrest. Women have been employed as vaccinators in a bid to encourage mothers to get their children immunised but this has proved “challenging”, admitted Zaffran.
Experts are also concerned about the threat of outbreaks in countries devastated by war and fighting, such as Syria and Democratic Republic of Congo (DRC).
While there have been no cases of wild polio virus in these areas, there have been cases of vaccine-derived polio virus (VDPV). These are rare strains of poliovirus that have genetically mutated from the strain contained in the oral polio vaccine and transmitted to children who have not been vaccinated. Last year, there were 74 such cases in Syria and 22 in DRC.
“The failure to stop the virus now would result in a great resurgence of polio and the possibility of 200,000 cases every year for the next 10 years,” said Zaffran. “Eradicating polio will be a major milestone in human history.”