Un agencies are preparing to start a mass polio vaccination program in Gaza this weekend, after Israel and Hamas agreed to a series of three-day localized pauses in fighting. The World Health Organization officials have said that 1.2 million polio vaccine doses have already been delivered to Gaza ahead of the rollout. The goal is to vaccinate more than 600,000 children after the first case of polio in 25 years was discovered in Gaza. Lucy Williamson reports.

Born a month before the Gaza war began, Abdul Rahman has played a role in pausing it, something world leaders have struggled to do. Earlier this month, Abdul Rahman was diagnosed with polio, the first case in Gaza for 25 years. The family, nine children in all, live in a camp in central Gaza, displaced multiple times from their home in the north. The constant moving disrupted his vaccinations. His mother says others in the camp are afraid and stop their children playing with them. The virus stopped his progress.

He stopped sitting, stopped walking, stopped crawling, and stopped moving. I want him to be treated. He wants to live and walk like other children.

Abdel Rahman's diagnosis has raised fresh alarm over conditions in Gaza's camps. The phased pause in fighting will will allow medics to vaccinate more than half a million children in stages across the territory. But the conditions that caused this crisis are worsening, say aid organizations, and their solutions are not straightforward.

Due to the insecurity, the damage, the road infrastructure, and population displacement, but also based on our experience with this campaigns globally and worldwide, the three days might not be enough. To achieve adequate vaccination.

Israel's Prime Minister was clear that this was not a ceasefire. The war has so far been resistant to both diplomacy and disease. But preventing another layer of tragedy is seen as one small victory, what the EU's foreign policy chief called a drop of hope in a sea of despair. Lucy Williamson, BBC News, Janine.

Well, Sam Rose, Director of Planning at UNRA, told me more about the vaccination program.

I mean, we're deeply, deeply concerned about the levels at which it may be at. There's one confirmed case that your reporter referred to. There may be many more because the health system here has been decimated largely over the past 10 months. The bombardments, the destruction of clinics, the collapse of water and sewage, solid The waste management infrastructure, the malnutrition. These are precisely the conditions in which a vaccine like this reemerges. A vaccine which had been eradicated for more than 25 years inside the Gaza Strip has reemerced. We're deeply, deeply concerned. At the same time, we welcome so much as everyone here does the respite for just a small amount of time from the bombings, from the evacuation orders that we hope will allow us to administer a successful campaign working closely with the World Health Organization, UNICEF, the Ministry of Health, and other partners. But as you said, this is a massive, massive effort. We just really, really hope that it will be successful for the children we're vaccinating.

The disease reemerging, of course, rather than the vaccine reemerging. But just explain for us how you actually get to all the children and how can you be sure that all the children there will be reached? Is Is three days enough?

Three days perhaps isn't enough, as your previous interviewee said. And this will be three days across three different areas of the Gaza Strip, the Southern governorates, the Middle governorates, and the the northern governors. The vaccines, most of them have now arrived in Gaza. The personnel who will administer those vaccines, who will register the children who are raising awareness amongst the community, have been hired, have been trained, are out there. But doing anything in Gaza right now is incredibly difficult. Surviving the night is very difficult. So we face a number of challenges. The fact that there will be causes, humanitarian causes, the fact that there will be no evacuation orders make our lives more easy. It means that we can distribute the vaccines, the fuel, the staff to the areas in which they need to Unra, my organization, will be vaccinating up to half of these children. We've taken on about 1100 of our personnel will be involved. And we'll be vaccinating at our primary health clinics that we have, at health points that we've set up in areas that people have been vaccinated to. We have mobile teams who work in the dozens and dozens of schools where hundreds of thousands of people are sheltering.

We will do what would previously have been house to house, but now is tent to tent, largely given the realities of the situation in which people live. But reaching that more or less magic number of 90% of children will be very difficult because we don't quite know how many children there are. We don't know how many are still alive. We certainly don't know precisely anyway.

Sam Rose, there, Dr. Planning at Unra.