Mukesh Kapila, a former World Health Organisation official, says while international agencies have done a good job of stockpiling polio vaccines in Gaza, “all bits of the puzzle have to fit in”.

“What that means is that humanitarian policies are respected. Confidence has to be built within the community to venture out of wherever they travel to the designated point and get back. We know from recent experiences that accidents have happened,” Kapila told Al Jazeera.

Palestinian parents will be concerned for the safety of their children and Israeli attacks on health facilities continue. Kapila noted the “rolling schedule” for administering the vaccines made the situation more complicated.

“These are very momentary pauses from morning till mid-afternoon in each area. Considering the travel logistics for people in Gaza, this is not going to be easy for them to come and go safely,” Kapila said.