Eradicating polio

Start a conversation about polio and the other person will probably look puzzled and say: “I thought polio had already gone.” Yet, a battle against wild poliovirus is ongoing in three remaining endemic countries (Afghanistan, Nigeria, and Pakistan).1 A form mutated from the oral vaccine, which also paralyses, caused outbreaks in Syria and the Democratic Republic of the Congo in 2017.2

Reducing the number children with polio paralysis from 1000 per day in 1988 to 22 in total in 2017 is a remarkable achievement.3 In the past few decades, however, deadlines for interrupting transmission of the poliovirus have been repeatedly missed and modified. Children and families continue to be harmed, frontline vaccinators have been murdered,4 staff morale has suffered in relentlessly stressful circumstances, countries free of polio have to keep vaccinating, and donors must continue to find the nearly $1bn (£736m; €842m) for each year that the goal is missed.5

Why is finishing the job proving so difficult? Most polio is invisible. …