‘What the hell is going on?’ Polio cases are vanishing in Pakistan, yet the virus won't go away
By Leslie RobertsJan. 11, 2018 , 1:00 PM
Just a year ago, poliovirus seemed on its last legs in Pakistan, one of its final strongholds. Polio cases were steadily falling, from 306 in 2014 to 54 in 2015, 20 in 2016, and, by last count, eight in 2017. Blood tests showed that, overall, immunity to the virus had never been higher, even among children aged 6 to 11 months, thanks to years of tireless vaccination campaigns. Surely, there were not enough susceptible kids to sustain transmission, and the virus would burn itself out within a year.
http://www.sciencemag.org/news/2018/01/what-hell-going-polio-cases-are-vanishing-pakistan-yet-virus-wont-go-away
