Even as India celebrated five years of being polio-free on Wednesday, a suicide bomber blew himself up outside a polio vaccination centre in neighbouring Pakistan and killed 15 people, mostly cops, there to accompany health workers setting out to give children polio drops.
India’s last wild polio case was reported in the Howrah district in West Bengal on January 13, 2011. Since then, the virus, which cripples and kills young children, has not infected anyone in India.
Its neighbours haven’t done as well. Pakistan and Afghanistan are the only two countries in the world where polio remains endemic and infection has never stopped. In 2015, Pakistan had 52 cases, Afghanistan had 19, while Myanmar reported two vaccine-derived polio cases.
While most of Pakistan is polio-free, the infection flourishes in the Federally Administered Tribal Areas, from where it periodically spreads to other parts of the country and beyond its borders.
The Quetta attack is the latest in a series of attacks on polio workers by the Taliban and other Islamist militant groups in Pakistan that have taken close to 100 lives since 2012. Polio vaccinators became targets after the CIA organised a fake vaccination drive to confirm Osama Bin Laden was living in the Pakistani military town of Abbottabad, where he was killed in 2011.
The Taliban was quick to declare all vaccinators were spies and issue a fatwa declaring polio drops were poison and a part of a global conspiracy to sterilise Muslims. The presence of GPS-trackers on polio-vaccine coolers to confirm whether vaccinators were going to their assigned destinations and giving polio drops to all the children who need it added fuel to the suspicion that health workers were agents of the devil and should be stopped and destroyed.
Frequent attacks forced Pakistan to stop largescale vaccinations through 2013, which resulted in polio cases soaring the next year to 306, the highest in 14 years. The most recent attack came in November 2015, when gunmen shot dead the head of an immunisation programme in the Khyber Pakhtunkhwa district of Swabi.
In 2009, india topped the world’s polio charts with 741 cases, which was close to half of the 1,604 polio cases reported from around the world. Intensive vaccination drives coupled with close case tracking and surveillance helped the country bring polio down to zero in less than two years. On Jan 13 this year, India completed half a decade of being polio free.
But with wild polio virus still thriving in neighbouring Pakistan and Afghanistan, India cannot let its guard down. Following the World Health Organisation’s International Travel and Health recommendations, all travellers to polio-affected areas have to carry a polio vaccination certificate before travel and people staying for more then four weeks in areas where transmission continues need an additional dose off polio drops or inactivated polio vaccine within four weeks to 12 months of travel.
In April, India will be among 155 countries that will stop using the trivalent oral polio vaccine and switch to the bivalent version of the vaccine, to stop vaccine-derived poliovirus cases.
Vaccine-derived poliovirus are very rare strains of polio that can mutate from the weakened poliovirus in the oral polio vaccine when a child’s immunisation is very low, allowing the vaccine virus to circulate amongst unprotected children for an extended period of time. In 2015, 27 vaccine-derived polio cases were reported across seven countries. Of these, 24 cases were in countries that had been free of polio for more than one year.
The wild poliovirus type 2 was eradicated from the world in September 2015, which made the type 2 component -- which causes 90% of vaccine-derived polio cases -- redundant. So switching from the trivalent vaccine that protects against all three polio strains to the bivalent vaccine that doesn’t contain type 2 is expected cut down the numbers of vaccine-derived polio cases.
Children got infected with vaccine-derived polio virus in seven countries in 2015, with four of them -- Pakistan, Guinea, Lao People’s Democratic Republic and Myanmar -- reporting outbreaks caused by type 2, and Madagascar, Nigeria and Ukraine (the first case of polio in Europe since 2010), with type 1. had type.
Despite the challenges, 2015 ended in an optimistic note. Only 71 polio cases were reported, the lowest ever. Africa has been free of polio for more than a year, with the last case in Somalia on August 11, 2014. Vaccines work against polio, and ensuring they reach every child can help stamp out the disease forever.