CNN  — 

Israel has agreed to a series of pauses in fighting in Gaza?in September?to allow young children in the enclave to be vaccinated for polio, according to United Nations and?Israeli officials.

The campaign, which will aim to vaccinate around 640,000 children across Gaza, comes after the highly infectious virus was found in sewage samples in the Strip in June.

Rik Peeperkorn, the World Health Organization’s (WHO) representative for the West Bank and Gaza, told a press briefing from a video link Thursday that the pause would start September 1 and will be split into three 3-day phases.

“We have a preliminary commitment for area-specific humanitarian pauses during the campaign,” he said, adding that the pauses will roll out first in “central Gaza for three days, followed by south Gaza and then followed by north Gaza.”

The return of polio to Gaza is a measure of the destruction wrought by more than 10 months of Israeli bombardment. Polio vaccine coverage in the enclave was estimated at 99% in 2022, but had dropped to below 90% at the start of this year, according to WHO data. Peeperkorn warned that more than 90% coverage was needed to stop the outbreak.

The virus mostly affects children under five years old, and can cause irreversible paralysis and even death. It’s highly infectious and there is no cure; it can only be prevented by immunization, WHO says.

An Israeli official confirmed to CNN that polio vaccinations will begin in Gaza on Sunday. Each phase of the vaccination campaign is expected to take around seven hours, and during those hours, the vaccines will be able enter the area on “pause” and be distributed.

Vaccinations will begin in the central Deir Al-Balah region from September 1 to 4, then in the southern Khan Younis region from September 5 to 8, and in Gaza City and northern Gaza from September 9 to 12, the Palestinian Ministry of Health in Ramallah said. The ministry also published maps showing the locations of each vaccination center.

Basem Naim, a member of Hamas’ political bureau, said the militant group welcomed the push for a pause in Gaza to implement the vaccination drive. “We are ready to cooperate with international organizations to secure this campaign,” he added.

A worker unloads a shipment of polio vaccines through the Karm Abu Salem crossing at a Gaza health ministry depot, on Sunday.

Earlier this month, Abdul Rahman, an 11-month-old boy, was diagnosed with the disease – Gaza’s first recorded case of polio in 25 years. His mother, Niveen Abu al-Jidyan, told CNN how her child went from feverish and vomiting to partially paralyzed.

“My child started to move and crawl at an early age. But suddenly everything went backwards. Suddenly, he was no longer crawling or moving or able to stand on his feet or even sit,” she said. “He will be one next month. He should be walking by now, but he suddenly stopped moving.”

Ahead of the expected pauses, Israel’s offensive in Gaza has continued. The World Food Programme (WFP), which delivers aid throughout the Strip, said earlier this week it is halting the movement of its employees after one of its vehicles, which it said was “clearly marked,” was targeted with repeated gunfire just meters from an Israeli checkpoint.

On Friday, US Deputy Ambassador to the United Nations said an Israeli investigation into the attack had found it was caused by a “communications error.” CNN has asked the Israeli military for more information.

Kate Phillips-Barrasso, the vice president of global policy and advocacy at Mercy Corps, a humanitarian group, told CNN Thursday that the success of the Gaza?polio?vaccination campaign “rests on real and reliable guarantees of safety — ones that have not been provided by the parties to this conflict over the last ten months.”

“Put simply, Gaza has become the most dangerous place in the world to be a child or a humanitarian worker,” she said.

Three-day periods ‘might not be enough’

The aim of the immunization campaign is to vaccinate about 640,000 children under the age of 10 with two doses each. According to Peeperkorn, 1.26 million doses of vaccines and 500 vaccine carriers have already been delivered to Gaza.

He warned that the three-day periods “might not be enough to achieve adequate vaccination,” adding that it “has been agreed, when needed, the campaign will be extended by one day per zone, or even more when necessary.”

He added that it would be a two-round vaccination campaign with a four-week interval between the first and second doses.

The?Hostages Families Forum, which campaigns for the release of?hostages?held by Hamas in Gaza, has also asked the WHO and the UN children’s agency, UNICEF, to include?the hostages in the ongoing polio vaccination campaign and all other health interventions.

A United States official told CNN that Secretary of State Antony Blinken pushed Israeli Prime Minister Benjamin Netanyahu in their meeting last week on the polio vaccinations, telling Netanyahu it had to be a top priority and it had to get done.

Netanyahu agreed to work with the US on the details, the official said. US Special Envoy Lise Grande for Middle East Humanitarian Issues has been leading that effort, working to finalize the details between the Israeli government and the UN, including what the pauses would like and how the vaccines would be delivered.

WHO is joined in the vaccination effort by the Palestinian Ministry of Health, the United Nations Children’s Fund, the UN Relief and Works Agency for Palestine Refugees and other partners. Each organization has been assigned a role in the technical and strategic “microplan” to execute the vaccine campaign.

For weeks, the organizations have emphasized that some kind of ceasefire — what they are calling a “polio pause”— would be crucial to the effort’s success, and even to contain the disease from spreading to the broader region.

CNN’s Jennifer Hansler, Irene Nasser and Christian Edwards contributed reporting.