Philippine health officials declared a polio outbreak in the country yesterday, nearly two decades after the World Health Organization declared it to be free of the highly contagious and potentially deadly disease.
Health Secretary Francisco Duque III said at a news conference that authorities have confirmed at least one case of polio in a three-year-old girl in southern Lanao del Sur province and detected the polio virus in sewage in Manila and in waterways in the southern Davao region.
Those findings are enough to declare an outbreak of the crippling disease in a previously polio-free country like the Philippines, he said.
The World Health Organization and the United Nations Children's Fund expressed deep concern over polio's reemergence in the country and said they would support the government in immunising children, who are the most susceptible, and strengthening surveillance.
"As long as one single child remains infected, children across the country and even beyond are at risk of contracting polio," UNICEF Philippines representative Oyun Dendevnorov said.
WHO and UNICEF said in a joint statement the polio outbreak in the Philippines is concerning because it is caused by vaccine-derived poliovirus type 2.
The weakened virus used in vaccines replicates for a short time in children's intestines and is excreted in their feces. In rare instances, they said, the weakened virus can strengthen in areas with poor sanitation and hygiene. Children who have not been properly immunised can be susceptible.
They said the last known case from a wild strain of the virus in the Philippines was in 1993. Wild poliovirus type 2 was declared globally eradicated in 2015.
There is no known cure for polio, which can only be prevented with vaccines.
Mr Duque said his department will launch a mass vaccination campaign next month for children under age 5, starting in the Manila metropolis, Lanao del Sur and Davao, where the virus was detected.
At least 95 per cent of children under age five need to be vaccinated to halt the spread of polio in the Philippines, WHO and UNICEF said.
Polio can cause paralysis and, in some cases, death.