The World Health Organisation (WHO) has said that a mass campaign to vaccinate children against polio in Gaza will resume on Saturday, with over half a million children targeted, Reuters reports.

“The current environment in Gaza, including overcrowding in shelters and severely damaged water, sanitation and hygiene infrastructure, which facilitates fecal-oral transmission, create ideal conditions for further spread of poliovirus,” the WHO statement said.

“Extensive population movement consequent to the current ceasefire is likely to exacerbate the spread of poliovirus infection,” it added.