Polio has re-emerged in several African countries where it had been eradicated, the World Health Organisation said Monday at the start of a conference on child immunisation in Zimbabwe.
"Several polio-free countries have suffered setback in polio eradication," WHO Africa regional director Luis Gomes Sambo told the 150 delegates.
"The number of countries with polio outbreaks following wild poliovirus importations has increased from 13 to 19 in 2009," he said at the conference, which runs through Thursday.
Sambo said the conference aims to find ways to reduce child mortality and to urge governments to increase funding for child vaccines.
"We need increased funding to improve the capacity of governments to budget vaccines," Sambo said.
Angola, Chad, the Democratic Republic of Congo and Nigeria are among the countries that have seen an increase in polio, due mainly to a lack of immunisations, WHO said.
About 74 percent of Africa's children receive routine vaccinations, but WHO says coverage of at least 85 percent is needed.