DEIR AL-BALAH, Gaza Strip  — Born into the devastating Israel-Hamas war, 10-month-old Abdel-Rahman Abu El-Jedian started crawling early. Then one day, he froze — his left leg appeared to be paralyzed.

The baby boy is the first confirmed case of polio inside Gaza in 25 years, according to the World Health Organization.

Abdel-Rahman was an energetic baby, said the child’s mother, Nevine Abu El-Jedian, fighting back tears. “Suddenly, that was reversed. Suddenly, he stopped crawling, stopped moving, stopped standing up, and stopped sitting.”

Health care workers in Gaza have been warning of the potential for a polio outbreak for months, as the humanitarian crisis unleashed by Israel’s offensive on the strip only grows. Abdel-Rahman’s diagnosis confirms health workers’ worst fears.

Before the war, Gaza’s children were largely vaccinated against polio, the WHO says.

But Abdel-Rahman was not vaccinated because he was born just before Oct. 7, when Hamas militants attacked Israel and Israel launched a retaliatory offensive on Gaza that forced his family into near-immediate flight. Hospitals came under attack, and regular vaccinations for newborns all but stopped.

The WHO says that for every case of paralysis due to polio, there are hundreds more who likely have been infected but aren’t showing symptoms. Most people who contract the disease do not experience symptoms, and those who do usually recover in a week or so. But there is no cure, and when polio causes paralysis, it is usually permanent. If the paralysis affects breathing muscles, the disease can be fatal.

The Abu El-Jedian family, like many, now live in a crowded tent camp, near heaps of garbage and dirty wastewater flowing into the streets that aid workers describe as breeding grounds for diseases like polio, spread through fecal matter. The United Nations has unveiled plans to begin a vaccination campaign to stop the spread and protect other families from the ordeal the Abu El-Jedian family now faces.

The family of 10 left their home in the northern Gaza town of Beit Lahiya, moving from shelter to shelter until finally settling in a tent in the central city of Deir al-Balah.

“My son was not vaccinated because of the continued displacement,” his mother said. “We are sheltering here in the tent in such health conditions where there is no medication, no capabilities, no supplements.”

The mother of eight said she was “stunned” to find out that her boy had contracted polio.

The WHO says that there are at least two other children with paralysis reported in the strip, and samples of their stool have been sent to a lab in Jordan.

In order to vaccinate most of Gaza’s children under the age of 10, UNICEF spokesperson Ammar Ammar said a cease-fire is necessary. The health agencies seek a pause in the fighting, which in recent days has sent thousands of Palestinian families fleeing under successive Israeli evacuation orders. Many children live in areas of Gaza that ongoing Israeli military operations make difficult to reach.

“Without the polio pause or cease-fire, it would be impossible,” Ammar said. “This is due to the continued evacuation orders and continued displacement of the children and their families. In addition, it can be extremely dangerous for teams as well, to be able to reach the children.”

The United Nations aims to vaccinate at least 95% of more than 640,000 children, beginning Saturday. Already 1.2 million doses of vaccine have arrived in Gaza, with 400,000 more doses set to arrive in the coming weeks, according to UNICEF. Israel’s military body in charge of civilian affairs, COGAT, said it allowed U.N. trucks carrying over 25,000 vials of the vaccine through the Kerem Shalom crossing Sunday.

“If this is not implemented, it could have a disastrous effect, not only for the children in Gaza, but also neighboring countries and across the borders in the region,” Ammar said.

Back in the family’s tent in Deir Al-Balah, Nevine Abu El-Jedian gazed at her youngest boy, lying still in a plastic car seat-turned bassinet as her seven other children gathered around.

“I hope he returns to be like his siblings, sitting down and moving,” she said.