Pakistan, March 22 -- Year after year, we pray for some magical swish for health authorities to declare that history has been made and Pakistan finally walked over to the safe side of the poliovirus divide. However, a variety of new hurdles continue to emerge in the fight to eradicate a disabling and life-threatening disease.

With at least nine sewage samples from as many as six districts found positive for wild poliovirus, we are in no position to let the guard down. More attention and significantly more resources are needed to maintain consistently high levels of vaccination in all children to ensure immunity across the country.

Eradicating a virus refuses to go away has emerged as a persistent challenge for the state, whose extensive...