Authorities in the Philippines have declared an outbreak of polio, with two cases reported up to September 24, both of which were caused by vaccine-derived poliovirus type 2 (VDPV2).
The first case was identified in a three-year-old girl in the southern Philippines. The case was confirmed on 14 September following testing by the National Polio Laboratory at the Research Institute for Tropical Medicine, the Japan National Institute of Infectious Diseases (NIID) and the United States Centers for Disease Control and Prevention (CDC).
The second case was confirmed on 19 September in a five-year-old boy. Investigations and further characterisation of the virus are ongoing.
In a statement, the World Health Organization (WHO) said the current risk of international spread from the Philippines is considered to be low. However, it said the risk of further spread within the Philippines is high due to limited population immunity and sub-optimal acute flaccid paralysis (AFP) surveillance.
The WHO is recommending that all travellers and residents in polio-affected areas to be fully vaccinated against polio. It said all countries, in particular those with frequent travel and contact with polio-affected countries and areas, should strengthen surveillance for AFP cases in order to detect virus importation.