Palestinian health authorities and United Nations agencies have begun a large-scale campaign of vaccinations against polio in the Gaza Strip, hoping to prevent an outbreak in the territory that has been ravaged by the ongoing Israel-Hamas war.

Authorities plan to vaccinate children in central Gaza until Wednesday, before moving on to the more devastated northern and southern parts of the strip.

The campaign began with a small number of vaccinations on Saturday and aims to reach about 640,000 children.

The World Health Organisation (WHO) said on Thursday that Israel has agreed to limited pauses in the fighting to facilitate the campaign. There were initial reports of Israeli strikes in central Gaza early on Sunday, but it was not immediately known if anyone was killed or injured.

Hospitals in Deir al-Balah and Nuseirat confirmed the campaign had begun on Sunday.

A medic in gloves administers the polio vaccine into the mouth of a girl
The vaccine is administered by oral drops (Abdel Kareem Hana/AP)

Gaza recently reported its first polio case in 25 years – a 10-month-old boy, now paralysed in the leg.

WHO says the presence of a paralysis case indicates there could be hundreds more who have been infected but are not showing symptoms.

Most people who have polio 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 vaccination campaign faces a host of challenges, from ongoing fighting to devastated roads and hospitals shut down by the war.

Around 90% of Gaza’s population of 2.3 million people have been displaced within the besieged territory, with hundreds of thousands crammed into squalid tent camps.

A mother tends to her child, who is lying on a hospital bed
A Palestinian child waits to receive a polio vaccination at a hospital in Khan Younis (Abdel Kareem Hana/AP)

Health officials have expressed alarm about disease outbreaks as uncollected rubbish has piled up and the bombing of critical infrastructure has sent putrid water flowing through the streets. Widespread hunger has left people even more vulnerable to illness.

Wafaa Obaid, who brought her three children to the Al-Aqsa Martyrs Hospital in Deir al-Balah to get the vaccinations, said: “We escaped death with our children, and fled from place to place for the sake of our children, and now we have these diseases.”

Ammar Ammar, a spokesman for the UN children’s agency, said it hopes both parties adhere to a temporary truce in designated areas to enable families to reach health facilities.

“This is a first step,” he said, “but there is no alternative to a ceasefire because it’s not only polio that threatens children in Gaza, but also other factors, including malnutrition and the inhuman conditions they are living in.”

The vaccinations will be administered at roughly 160 sites across the territory, including medical centres and schools. Children under 10 will receive two drops of oral polio vaccine in two rounds, the second to be administered four weeks after the first.

Israel allowed around 1.3 million doses to be brought into the territory last month, which are now being held in refrigerated storage in a warehouse in Deir al-Balah. Another shipment of 400,000 doses is set to be delivered to Gaza soon.