The World Health Organization announced that Israel and Hamas have given a “preliminary commitment” to conduct “humanitarian pauses” to allow the global body to begin a polio vaccination campaign, starting this Sunday, in the Gaza Strip.

Dr. Rik Peeperkorn, the WHO representative in the Palestinian-controlled territories, told reporters on Thursday that the organization will spend three days each in the central, southern and northern parts of the Strip in an attempt to vaccinate at least 90% of the population, particularly children.

That rate, which Peeperkorn said is required to stem a potential outbreak of the disease—once among the most feared in the United States—is achievable, he said. He acknowledged the challenges, including a breakdown of infrastructure and safety in Gaza.

The first confirmed case of polio in a quarter century was a 10-month-old baby in Gaza born just before Hamas’s terrorist attacks in southern Israel on Oct. 7. Children in the coastal enclave were largely vaccinated before the war, but hundreds of thousands have missed vaccinations since, according to the WHO.

Peeperkorn left the nature and parameters of the pauses largely undefined but said they would take place daily between 6 a.m. and 3 p.m., local time. The WHO might need more than three days in each region to get the job done, and there is an agreement in place to add a fourth day in a zone if necessary, he said.

The WHO has also secured an agreement from Israel not to issue evacuation orders in a region of Gaza where the vaccination campaign is taking place, Peeperkorn said.

It aims to vaccinate 640,000 children under 10 years of age.

“I’m not going to say this is the ideal way forward, but this is a workable way forward,” said the WHO representative of the pauses.

The agreement on pauses for the polio vaccinations are separate from larger negotiations between Israel and Hamas, via intermediaries in Qatar, Egypt and the United States, for a deal that would include a ceasefire and hostage release, in exchange for security prisoners.

Hamas official Basem Naim told Reuters that the terror group is “ready to cooperate with international organizations to secure this campaign, serving and protecting more than 650,000 Palestinian children in the Gaza Strip.”

JNS sought comment from the Coordination of Government Activities in the Territories, the Israeli military body responsible for coordinating civilian life in Gaza, including humanitarian aid.

COGAT stated on Sunday “polio vaccines for 1.255 million people were delivered to Gaza today via the Kerem Shalom Crossing.”

“This is done in coordination with WHO and UNICEF, and as part of our humanitarian efforts. In the coming days, international and local medical teams will vaccinate children who have not yet been vaccinated against polio at various locations in Gaza,” COGAT stated.

“The vaccination campaign in Gaza led by WHO and UNICEF will be conducted in coordination with the IDF through COGAT, as part of the routine humanitarian pauses that will allow the population to reach the medical centers where the vaccinations will be administered,” it added.

Dr. Peeperkorn stated the campaign will involve providing two drops of the novel oral polio vaccine, and WHO’s efforts will be supported by UNICEF, Hamas’s health ministry and other partners.

The second dose will be given four weeks after the first, and there are nearly 400 fixed sites for vaccinations across Gaza.