Africa celebrated one year since the last case of polio was recorded in Somalia on August 11, 2014, News Vision reports.

However, health officials have to wait another two years before it can declare the African continent free from polio.

The UN children's agency UNICEF called it an "extraordinary achievement" but warned that further success depended on the continuation of vaccination program and close observation of possible cases.

If Africa is declared polio-free, it would leave only Pakistan and Afghanistan where the disease had not been wiped out, according to the World Health Organization (WHO).

"We have had no new cases for a year despite all the challenges in the country,"UNICEF's chief for Somalia Steven Lauwerier told AFP on Wednesday. "We never want to see another Somali child being paralysed by this preventable virus. That means we need to continue to support the vaccination campaigns to ensure polio is completely eradicated."

According to News Vision, UNICEF polio chief Peter Crowley said, referring to the eradication of smallpox, "Globally, we are on the verge of totally eradicating a disease for only the second time in history."

The elimination of polio is "a powerful symbol of the progress that has been made on the African continent over the past generation", Crowley said.

However, it has also warned there may have been unrecorded polio cases in Africa.