Polio cases are rising ahead of a new vaccination campaign in Pakistan, where violence targeting health workers and the police protecting them has hampered years of efforts toward making the country polio-free.

Every paralytic polio case means there are hundreds of children who are silently affected by poliovirus and are potentially carrying and spreading it throughout their communiti

Pakistan said Saturday that two children in its southern Sindh province had been paralyzed by poliovirus, bringing the total number of cases nationwide to 39 for the year since March, when officials confirmed the first case.