The reemergence of polio in Gaza after 25 years has sent alarm bells ringing among health experts, who have warned of a potentially catastrophic outbreak that could compound the already dire humanitarian situation of thousands of children trapped in the conflict-torn enclave.Given this, the World Health Organization (WHO) is set to launch a massive vaccination campaign in Gaza on Sunday.For all the latest headlines follow our Google News channel online or via the app.The latest case of polio – that has led to paralysis in a child named Abdul-Rahman Abu Al-Jidyan, aged about one year – has accelerated plans for a widespread immunization program, targeting more than 640,000 children across the Palestinian Territory.A three-day pause in fighting in each of Gaza’s three zones has been agreed upon by Israel and Hamas to allow thousands of UN workers to administer polio vaccines.Poliomyelitis, which is spread mainly through the fecal-oral route, is a highly infectious virus that can invade