Emergence of vaccine-derived poliovirus type 2 after using monovalent type 2 oral poliovirus vaccine in an outbreak response, Philippines

Emergent VDPV2 after mOPV2 use in the Philippines

Authors

  • SweetC B. Alipon Vaccine-Preventable Diseases and Immunization, Division of Programmes for Disease Control, World Health Organization Regional Office for the Western Pacific, Manila, Philippines
  • Yoshihiro Takashima Vaccine-Preventable Diseases and Immunization, Division of Programmes for Disease Control, World Health Organization Regional Office for the Western Pacific, Manila, Philippines
  • Tigran Avagyan Vaccine-Preventable Diseases and Immunization, Division of Programmes for Disease Control, World Health Organization Regional Office for the Western Pacific, Manila, Philippines
  • Varja Grabovac Vaccine-Preventable Diseases and Immunization, Division of Programmes for Disease Control, World Health Organization Regional Office for the Western Pacific, Manila, Philippines
  • Syeda Kanwal Aslam Vaccine-Preventable Diseases and Immunization, Division of Programmes for Disease Control, World Health Organization Regional Office for the Western Pacific, Manila, Philippines
  • Benjamin Bayutas Vaccine-Preventable Diseases and Immunization, Division of Programmes for Disease Control, World Health Organization Regional Office for the Western Pacific, Manila, Philippines
  • Josephine Logronio Vaccine-Preventable Diseases and Immunization, Division of Programmes for Disease Control, World Health Organization Regional Office for the Western Pacific, Manila, Philippines
  • Xiaojun Wang World Health Organization Representative Office for the Philippines, Manila, Philippines
  • Achyut Shrestha World Health Organization Representative Office for the Philippines, Manila, Philippines
  • Sukadeo Neupane World Health Organization Representative Office for the Philippines, Manila, Philippines
  • Maria Concepcion Roces World Health Organization Representative Office for the Philippines, Manila, Philippines
  • Lea Necitas Apostol Research Institute for Tropical Medicine, Department of Health, Manila, Philippines
  • Nemia Sucaldito Public Health Surveillance Division, Department of Health, Manila, Philippines

DOI:

https://doi.org/10.5365/wpsar.2022.13.2.904

Abstract

Objective: In response to an outbreak of circulating vaccine-derived poliovirus (cVDPV) type 2 in the Philippines in 2019–2020, several rounds of supplementary immunization activities using the monovalent type 2 oral poliovirus vaccine (OPV) were conducted for the first time in the Western Pacific Region. After use of the monovalent vaccine, the emergence of vaccine-derived poliovirus unrelated to the outbreak virus was detected in healthy children and environmental samples. This report describes the detection of this poliovirus in the Philippines after use of the monovalent type 2 OPV for outbreak response.

Methods: We describe the emergence of vaccine-derived poliovirus unrelated to the outbreak detected after supplementary immunization activities using the monovalent type 2 OPV. This analysis included virus characterization, phylogenetic analyses and epidemiological investigations.

Results: Three environmental samples and samples from six healthy children tested positive for the emergent vaccine-derived poliovirus. All isolates differed from the Sabin type 2 reference strain by 6–13 nucleotide changes, and all were detected in the National Capital Region and Region 4, which had conducted supplementary immunization activities.

Discussion: Since the 2016 removal of type 2 strains from the OPV, vaccine-derived poliovirus outbreaks have occurred in communities that are immunologically naive to poliovirus type 2 and in areas with recent use of monovalent OPV. To prevent the emergence and further spread of cVDPV type 2, several interventions could be implemented including optimizing outbreak responses by using the monovalent type 2 OPV, accelerating the availability of the novel type 2 OPV, strengthening routine immunization using inactivated polio vaccine and eventually replacing OPV with inactivated poliovirus vaccine for routine immunization.

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Published

25-05-2022

Issue

Section

Outbreak Investigation Report