A 10-month-old baby has been partially paralysed after contracting polio in Gaza, United Nations officials have said.

According to the UN, Gaza, now in its 11th month of war, has not registered a polio case for 25 years, although type 2 poliovirus was detected in samples collected from the territory’s wastewater in June.

The head of the World Health Organization (WHO), Tedros Adhanom Ghebreyesus, said he is “gravely concerned” and confirmed that efforts are under way to roll out a vaccination programme in the coming weeks.

The 10-month-old, who was unvaccinated, is said to be in a stable condition after developing paralysis in one leg.

Poliovirus, most often spread through sewage and contaminated water, is highly infectious.

It can cause disfigurement and paralysis, and is potentially fatal. It mainly affects children under the age of five.

Humanitarian groups have blamed the re-emergence of polio in Gaza on disruption to child vaccination programmes and massive damage to water and sanitation systems caused by the war.

In order to try to contain the spread, the UN has been pressing for a week-long pause in fighting to carry out a polio vaccination campaign for more than 640,000 children under the age of 10.

UN Secretary General António Guterres said “hundreds of thousands of children in Gaza [are] at risk”.

He said that for the campaign to be successful, transport of vaccines and required equipment would need to be facilitated, as well as the entry of polio experts into Gaza.

Adequate fuel, increased flow of cash, reliable communications and the ensured safety of both health workers and people reaching health facilities were also needed, he said.

WHO has approved the release of 1.6 million doses of vaccine, UNICEF is coordinating their delivery along with cold storage units and UNRWA’s medical teams will administer the vaccines once they arrive in Gaza.

UNICEF’s Executive Director Catherine Russel said that the re-emergence of the virus in the strip after 25 years is “another sobering reminder of how chaotic, desperate and dangerous the situation has become”.

On 18 August, the Israel Defense Forces (IDF) said since the beginning of the war, 282,126 vials of the polio vaccine, sufficient for 2,821,260 doses, have been sent to Gaza.

It said in the coming weeks, an additional 60,000 vaccines will be delivered to vaccinate over one million children.

According to the IDF, entry to the Gaza Strip for vaccines and epidemic prevention is being facilitated by the Coordinator of Government Activities in the Territories (COGAT),

“This includes the entry of medical teams and vaccines against the polio virus,” the IDF said.

Israel launched a military campaign in Gaza in response to an unprecedented attack on southern Israel on 7 October by Hamas gunmen, during which about 1,200 people were killed and 251 taken hostage.

More than 40,265 people have been killed in Gaza since then, according to the territory’s Hamas-run health ministry, which does not give details of civilian and combatant deaths. The UN human rights office says most of those killed were women and children.