Somalia

Status: affected by circulating vaccine-derived poliovirus

Circulation of vaccine-derived poliovirus type 2 (cVDPV2) has been confirmed in Somalia.  Three VDPV2s were isolated from environmental samples collected 4 and 11 January 2018, from Hamarweyn district in Banadir province (Mogadishu).  These isolates are genetically linked to previously isolated VDPV2s from 2017, collected on 22 October and 2 November 2017 from environmental samples collected from Waberi district, Banadir province.  No cases of acute flaccid paralysis (AFP) associated with this cVDPV2 have been detected at this time – the viruses were all isolated from environmental samples. Surveillance for AFP cases in the area is being strengthened.

Since detection of the initial isolates in 2017, outbreak response campaigns in line with internationally-agreed guidelines have been implemented, consisting of two large-scale immunization activities (SIAs) in Banadir, Lower Shabelle and Middle Shabelle provinces. Further response based on evolving epidemiology and ongoing risk assessment is being evaluated.  Surveillance for AFP cases is being strengthened.  WHO and its partners are continuing to support local public health authorities in conducting field investigations and risk assessments to more clearly assess any potential risk of circulation of the identified cVDPV2, and to continue to support the outbreak response and strengthening of disease surveillance.

The detection of cVDPV2 underscores the importance of maintaining high levels of routine vaccination coverage at all levels to minimize the risk and consequences of any poliovirus circulation. Such events also underscore the risk in areas or regions with continued substantial insecurity that hampers maintaining high population immunity through routine vaccination. A robust outbreak response is needed to rapidly stop the VDPV2 transmission. WHO will continue to evaluate the epidemiological situation and outbreak response measures being implemented.

Polio this week in Horn of Africa

  • Circulation of vaccine-derived poliovirus type 2 (cVDPV2) has been confirmed in Somalia.
  • Three vaccine-derived poliovirus type 2s (VDPV2s) were isolated from two environmental samples collected in Hamarweyn district, Banadir province (Mogadishu), one on 4 January, and one on 11 January 2018. These latest isolates are genetically linked to previously isolated VDPV2s from 2017, collected on 22 October and 2 November from environmental samples collected from Waberi district, Banadir province. In total, four environmental samples (with seven unique virus sequences) positive for cVDPV2 have been collected in Somalia between October 2017, and January 2018.
  • No cases of acute flaccid paralysis (AFP) associated with this cVDPV2 have been detected at this time – the viruses were all isolated from environmental samples.
  • Surveillance for AFP cases in the area is being strengthened.
  • Since detection of the initial isolates in 2017, outbreak response campaigns in line with internationally-agreed guidelines have been implemented, consisting of two large-scale immunization activities (SIAs) in Banadir, Lower Shabelle and Middle Shabelle provinces. A third SIA is planned for March 2018, and further response based on evolving epidemiology and ongoing risk assessment is being evaluated.
  • WHO and its partners are continuing to support local public health authorities in conducting field investigations and risk assessments to more clearly assess any potential risk of circulation of the identified cVDPV2, and to continue to support the outbreak response and strengthening of disease surveillance.
  • Read our Somalia country page to see information on surveillance and vaccination campaigns.
  • Learn more about vaccine-derived polioviruses through this short animation or this ‘Coffee with Polio Experts’ video.

Travel advice

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.

More on vaccine-derived polioviruses