Health officials in Zimbabwe have started a nationwide campaign to vaccinate two million children against polio, UNICEF said Wednesday, according to dpa. The campaign, launched on Monday, aims to see all under-fives in Zimbabwe vaccinated against the debilitating disease, said the UN children's body in a statement. Zimbabwe was declared polio-free in 1999 but is under threat from outbreaks in nearby countries like Botswana. The campaign will last for a week and is being funded with support from the UK, Ireland and Canada, according to the statement. Zimbabwe's public health service is in dire shape as the ravages of sky-high inflation currently running at more than 3,700 per cent robs institutions of skilled staff and make it nearly impossible to procure essential drugs. The campaign comes at a critical time as families are under ever- greater pressure from record-high inflation, unemployment and orphan numbers and severe economic stresses, said the UNICEF statement. UNICEF country representative Festo Kavishe said the polio immunization campaign provided a critical boost to Zimbabwe's health services.