Status: affected by circulating vaccine-derived poliovirus

In Myanmar, genetically-linked circulating vaccine-derived poliovirus type 1 (cVDPV1) has been isolated from two separate acute flaccid paralysis (AFP) cases, with onset of paralysis on 22 May and 14 June, from Kayin province.   These linked viruses have 27 and 25 nucleotide changes from Sabin 1.

Myanmar’s routine immunization coverage is strong, estimated at 89% for bivalent OPV.  Neighbouring countries have been informed of the confirmed cVDPV1, and subnational surveillance is being strengthened across the region

The Ministry of Health and local health authorities are undertaking a detailed investigation and the partners of the Global Polio Eradication Initiative (GPEI) are providing support as required.  A full epidemiological and virological field investigation is ongoing, including to ascertain the source and origin of the isolated viruses; active surveillance is being strengthened; subnational population immunity levels are being analysed; and, outbreak response is being planned.

Polio this week in Myanmar

  • No circulating vaccine-derived poliovirus type 1 (cVDPV1) cases were reported this week. There are six reported cases of cVDPV1 in 2019.
  • Learn more about vaccine-derived polioviruses through this short animation or this ‘Coffee with Polio Experts’ video.
  • Read our Myanmar country page to see information on cases, surveillance and response to the developing outbreak.

WHO risk assessment

WHO currently assesses the risk of international spread of this confirmed cVDPV1 to be low.

WHO advice

It is important that all countries, in particular those with frequent travel and contacts with polio-affected countries and areas, strengthen surveillance for AFP cases in order to rapidly detect any new virus importation and to facilitate a rapid response. Countries, territories and areas should also maintain uniformly high routine immunization coverage at the district level to minimize the consequences of any new virus introduction.

WHO’s International Travel and Health recommends that all travellers to polio-affected areas be fully vaccinated against polio. Residents (and visitors for more than 4 weeks) from infected areas should receive an additional dose of OPV or inactivated polio vaccine (IPV) within 4 weeks to 12 months of travel.

As per the advice of an Emergency Committee convened under the International Health Regulations (2005), efforts to limit the international spread of poliovirus remains a Public Health Emergency of International Concern (PHEIC).  Countries affected by poliovirus transmission is subject to Temporary Recommendations.  To comply with the Temporary Recommendations issued under the PHEIC, any country infected by poliovirus should declare the outbreak as a national public health emergency and consider vaccination of all international travellers.