Inside STAT: 'The switch’ was supposed to help eradicate polio. Now it’s a quandary

A CHILD IS VACCINATED AGAINST POLIO IN KAJIADO, KENYA. (YASUYOSHI CHIBA/AFP/GETTY IMAGES)

Three years ago, public health experts made the switch from a type of vaccine that immunized  against three types of poliovirus — types 1, 2, and 3 — to a version that no longer included protection against type 2 polioviruses. Why? Because in 2015, those viruses were declared eradicated and vaccinating children against type 2 viruses occasionally caused paralysis. In most parts of the world the switch went well, but in parts of Africa, outbreaks caused by type 2 vaccine viruses are forcing the polio eradication campaign to ask itself a very tough question: Should it switch back? A new vaccine that should solve the problem will be available in mid-2020. Can the program wait? STAT’s Helen Branswell has more.