title: Multiple independent emergences of type 2 vaccine-derived polioviruses during a large outbreak in northern Nigeria.
abstract: Since 2005, a large poliomyelitis outbreak associated with type 2 circulating vaccine-derived poliovirus (cVDPV2) has occurred in northern Nigeria, where immunization coverage with trivalent oral poliovirus vaccine (tOPV) has been low. Phylogenetic analysis of P1/capsid region sequences of isolates from each of the 403 cases reported in 2005 to 2011 resolved the outbreak into 23 independent type 2 vaccine-derived poliovirus (VDPV2) emergences, at least 7 of which established circulating lineage groups. Virus from one emergence (lineage group 2005-8; 361 isolates) was estimated to have circulated for over 6 years. The population of the major cVDPV2 lineage group expanded rapidly in early 2009, fell sharply after two tOPV rounds in mid-2009, and gradually expanded again through 2011. The two major determinants of attenuation of the Sabin 2 oral poliovirus vaccine strain (A481 in the 5'-untranslated region [5'-UTR] and VP1-Ile143) had been replaced in all VDPV2 isolates; most A481 5'-UTR replacements occurred by recombination with other enteroviruses. cVDPV2 isolates representing different lineage groups had biological properties indistinguishable from those of wild polioviruses, including efficient growth in neuron-derived HEK293 cells, the capacity to cause paralytic disease in both humans and PVR-Tg21 transgenic mice, loss of the temperature-sensitive phenotype, and the capacity for sustained person-to-person transmission. We estimate from the poliomyelitis case count and the paralytic case-to-infection ratio for type 2 wild poliovirus infections that ∼700,000 cVDPV2 infections have occurred during the outbreak. The detection of multiple concurrent cVDPV2 outbreaks in northern Nigeria highlights the risks of cVDPV emergence accompanying tOPV use at low rates of coverage in developing countries.
authors: Division of Viral Diseases, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, USA. CBurns@cdc.gov
authors: Cara C
authors: CC
authors: Burns
authors: Jing
authors: J
authors: Shaw
authors: Jaume
authors: J
authors: Jorba
authors: David
authors: D
authors: Bukbuk
authors: Festus
authors: F
authors: Adu
authors: Nicksy
authors: N
authors: Gumede
authors: Muhammed Ali
authors: MA
authors: Pate
authors: Emmanuel Ade
authors: EA
authors: Abanida
authors: Alex
authors: A
authors: Gasasira
authors: Jane
authors: J
authors: Iber
authors: Qi
authors: Q
authors: Chen
authors: Annelet
authors: A
authors: Vincent
authors: Paul
authors: P
authors: Chenoweth
authors: Elizabeth
authors: E
authors: Henderson
authors: Kathleen
authors: K
authors: Wannemuehler
authors: Asif
authors: A
authors: Naeem
authors: Rifqiyah Nur
authors: RN
authors: Umami
authors: Yorihiro
authors: Y
authors: Nishimura
authors: Hiroyuki
authors: H
authors: Shimizu
authors: Marycelin
authors: M
authors: Baba
authors: Adekunle
authors: A
authors: Adeniji
authors: A J
authors: AJ
authors: Williams
authors: David R
authors: DR
authors: Kilpatrick
authors: M Steven
authors: MS
authors: Oberste
authors: Steven G
authors: SG
authors: Wassilak
authors: Oyewale
authors: O
authors: Tomori
authors: Mark A
authors: MA
authors: Pallansch
authors: Olen
authors: O
authors: Kew
mesh_terms: D000818:Animals; D036022:Capsid Proteins / Q000235:genetics / Q000276:immunology; D004196:Disease Outbreaks; D005260:Female; D006801:Humans; D008297:Male; D051379:Mice; D008969:Molecular Sequence Data; D009549:Nigeria / Q000453:epidemiology; D010802:Phylogeny; D011051:Poliomyelitis / Q000453:epidemiology* / Q000821:virology; D017955:Poliovirus / Q000145:classification / Q000235:genetics / Q000276:immunology / Q000502:physiology*; D011055:Poliovirus Vaccine, Oral / Q000008:administration & dosage / Q000009:adverse effects*; D023321:Poliovirus Vaccines / Q000009:adverse effects* / Q000235:genetics / Q000276:immunology
chemical_list: D036022:Capsid Proteins; D011055:Poliovirus Vaccine, Oral; D023321:Poliovirus Vaccines; C442540:VP1 protein, Poliovirus; C442541:VP2 protein, Poliovirus