The U N children’s agency says a polio vaccination campaign in Gaza reached 189,000 children, surpassing its target and providing a “rare bright spot” in nearly 11 months of war.

UNICEF said Wednesday that more than 500 teams deployed across central Gaza this week, administering the vaccine to children under 10.

It said Israel and Hamas observed limited pauses in the fighting to facilitate the campaign. U.N. agencies now hope to expand the campaign to the harder-hit north and south of the territory. They hope to vaccinate a total of 640,000 children.

The campaign was launched after Gaza had its first reported polio case in 25 years — a 10-month-old boy, now paralyzed in the leg.

Health experts have warned of disease outbreaks in the territory, where the vast majority of people have been displaced, often multiple times, and where hunger is widespread.

Hundreds of thousands of people are crammed into squalid tent camps with few if any public services as Israel continues into offensive, which has killed more than 40,800 people in Gaza, according to Gaza’s Health Ministry. The war began when Hamas-led militants stormed into southern Israel on Oct. 7, killing some 1,200 people, mostly civilians, and abducting around 250 people.

"While these polio 'pauses' are giving people some respite, what is urgently needed is a permanent ceasefire, the release of all hostages and the standard flow of humanitarian supplies including medical and hygiene supplies (into Gaza)," Philippe Lazzarini, the head of the UN's main agency for Palestinian refugees wrote on X.

Despite the success of the polio campaign, diplomatic efforts to secure a permanent ceasefire, release hostages held in Gaza and return many Palestinians jailed by Israel, have faltered.