WHO said in a news release that more than 591,000 children under 10 years old will receive the vaccine to protect them from the highly infectious disease, beginning this weekend for an anticipated period of five days.

The campaign follows the recent detection of poliovirus in wastewater samples in the shattered enclave which signal that the infection is still circulating in the enclave and putting children at risk.

“Individuals with low or no immunity provide the virus an opportunity to continue spreading and potentially cause disease,” WHO said.

The UN health agency added that dreadful sanitary conditions in Gaza which include overcrowding in shelters and severely damaged water and sewer networks had created “ideal conditions for further spread of poliovirus”.

The mass return of people to north and south Gaza during the ongoing ceasefire is also likely to increase the spread of polio, WHO warned.

The campaign will be led by the Palestinian Ministry of Health with support from WHO, UN children’s agency UNICEF, the Palestine refugee relief agency (UNRWA) and other partners.

The agency stressed that polio vaccines are safe and there is no maximum number of times a child should be vaccinated, with each dose providing extra protection. An additional round of shots is planned for April.

Water trickling back online

Humanitarians in the enclave are working to increase the production and distribution of water supplies for both drinking and domestic use, said UN Spokesperson Stéphane Dujarric, briefing reporters in New York on Wednesday.

There are now more than 1,780 operational water points across the strip – over 85 per cent of them being used to support water trucking activities by our partners.

Aid partners are also training and deploying mobile teams and volunteers at aid distribution points to ensure that vulnerable groups – including people with disabilities – have safe and dignified access.

“More than 100 such teams are operating at nearly 70 aid distribution points throughout Gaza,” he said.

Meanwhile, in the occupied West Bank, UN humanitarian affairs office, OCHA, said Israeli operations in northern areas continue, causing further destruction and displacement for Palestinian families living there.

In Tulkarm refugee camp on Tuesday, humanitarian partners report that Israeli forces demolished at least five homes, and several others also slated by them for demolition.