The third phase of a giant polio vaccination drive targeting children in Gaza began Tuesday in a particularly war-ravaged zone, but the WHO said a support convoy had to abort its mission. After the first confirmed polio case in 25 years, a massive vaccination effort began last week targeting over 640,000 children under 10, aided by localised “humanitarian pauses” in fighting. After covering central and southern Gaza, the campaign moved into its final phase in the north from Tuesday until Thursday, said World Health Organization spokesman Tarik Jasarevic. Maher Shamiya, the deputy health minist…