WHO has published Circulating vaccine-derived poliovirus type 2 – Democratic Republic of the Congo. Excerpt:
In the Democratic Republic of the Congo, three different circulating vaccine-derived poliovirus type 2 (cVDPV2) outbreaks have been detected in acute flaccid paralysis (AFP) cases. In February 2018, the government declared cVDPV2 to be a national public health emergency.
The cVDPV2 strain initially detected and reported in June 2017 from Haut Lomami Province spread in late 2017 and early 2018 to Tanganyika and Haut Katanga provinces, respectively. The same virus was confirmed in Ituri Province in June 2018, close to the border with Uganda, from an AFP case with onset of paralysis on 5 May 2018. Investigations are ongoing.
WHO assessed the overall public health risk at the national level to be very high and the risk of international spread to be high due to the proximity of the recent detection of the AFP case in Ituri which is close to an international border and with known population movement.
Maniema Province is affected by a separate cVDPV2 outbreak, with two cases confirmed in 2017. The date of onset of paralysis of the most recent case was 18 April 2017. So far, no new cases have been detected in 2018, and there is no evidence that this virus has spread further geographically.
The third and most recently detected outbreak of cVDPV2 was found in Mongala Province and isolated from an AFP case in the Yamongili Health Zone. The onset date of paralysis was 26 April 2018. Circulation of the strain was confirmed when the same strain was isolated in stool specimens from two healthy community contacts.
Public health response
WHO and partners are responding to these outbreaks, including through the use of monovalent oral polio vaccine type 2 (mOPV2) in line with internationally-agreed upon outbreak response protocols. However, operational gaps in the response continue to hamper the full implementation of these protocols, as high-risk populations remain under-immunized, and the response thus far has not controlled the outbreak nor prevented its spread.
The geographic extent of the outbreak response to all three strains is now being re-evaluated, given the confirmed spread of one of the strains to Ituri and confirmation of the new strain in Mongala.
Surveillance and immunization activities are being strengthened in neighbouring countries.
In February 2018, the government declared cVDPV2 to be a national public health emergency. The remaining operational gaps in the outbreak response must be urgently addressed.
