A polio vaccination campaign has started in Gaza, an ambitious effort by health authorities to vaccinate 640,000 Palestinian children against the backdrop of a devastating war that has destroyed the territory's healthcare system.

The campaign comes after the first polio case in 25 years was reported in Gaza involving a 10-month-old boy who is now paralyzed in one leg.

According to the World Health Organization (WHO), the presence of a paralysis case indicates there could be hundreds more cases of children who have been infected but aren’t 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 targets children under 10 and aims to have at least 90 per cent of them vaccinated, according to the WHO.

Displaced infant Abdel-Rahman Abu El-Jedian, 11-month-old, who suffers from polio, is carried by his mother, center, at a makeshift tent camp in Deir al-Balah, central Gaza St

Displaced infant Abdel-Rahman Abu El-Jedian, 11-month-old, who suffers from polio, is carried by his mother, center, at a makeshift tent camp in Deir al-Balah, central Gaza StAbdel Kareem Hana/Copyright 2023, The AP. All rights reserved

Each child will receive two drops of the oral polio vaccine in two rounds, the second to be administered four weeks after the first.

The mission will involve over 2,100 health workers from UN agencies and the Ministry of Health in Gaza.

Director General of the WHO, Teodros Ghebreyesus, said that the campaign will start in the central area of Gaza and then continue in the south of the Strip and finally in the north.

Observers warn the vaccination effort will not be easy as Gaza’s roads are largely destroyed, its hospitals badly damaged, and its population spread into isolated pockets.

The UN estimates that approximately 65% of the total road network in Gaza has been damaged and 19 of the strip's 36 hospitals are out of service.

The north of the territory is cut off from the south, and travel between the two areas has been challenging throughout the war because of Israeli military operations. Aid groups have had to suspend trips due to security concerns after convoys were targeted by the Israeli military.