The World Health Organization (WHO) has reported on an outbreak of vaccine-derived poliovirus type 2 (cVDPV2) in Nigeria. The outbreak was confirmed on 5 June of this year and the country is also being affected by an ongoing separate cVDPV2 outbreak.
A WHO risk assessment that was performed before the outbreak response concluded that there was a high risk of geographical spread of the two outbreak virus strains, underscoring the importance of maintaining high levels of routine polio vaccination coverage at all levels to minimise the risk and consequences of any poliovirus circulation.
WHO’s advice is for all countries, particularly those with frequent travel and contact with polio-affected countries and areas, to strengthen surveillance for acute flaccid paralysis (a disease associated with cVDPV2) in order to ‘rapidly detect any polio case, implement preventive measures, and undertake rapid response if needed’.
All travellers to polio-affected areas are recommended by WHO’s International Travel and Health to be fully vaccinated against polio. WHO also advises that residents (and visitors for more than four weeks) from infected areas should receive an additional dose of oral polio vaccine or inactivated polio vaccine between four weeks and 12 months prior to departure.