623. Oral Polio Vaccine Circulation and Mutation after Mexican National Immunization Weeks
Session: Poster Abstract Session: Pediatric Vaccines
Friday, October 21, 2011
Room: Poster Hall B1
Handouts
  • 623 SBT_2011_Mex_IDSA_poster_v2.pdf (1.4 MB)
  • *The first two authors contributed equally to this work.

    Background:  Oral polio vaccine (OPV) can mutate and cause outbreaks of paralytic poliomyelitis with prolonged replication.  After poliovirus eradication, one proposed strategy to phase out vaccination is to globally use inactivated polio vaccine (IPV) until all OPV stops circulating.  Mexico, where children receive routine IPV but where OPV is given biannually during national immunization weeks (NIWs), provides a natural setting to study duration of OPV circulation in a community primarily vaccinated with IPV.

    Methods:  This study represents preliminary data from a year-long, longitudinal study in Orizaba, Mexico, collecting one liter sewage samples from four separate arroyos monthly starting 3 months after the May 2010 NIW.  Sewage was concentrated by vacuum filtration and then underwent RNA extraction, reverse transcription, and real time PCR to detect OPV serotypes 1, 2, and 3 and their mutant VAPP (vaccine associated paralytic poliomyelitis) variants.

    Results:  OPV was detected 3, 4, 5, and 7 months after the May 2010 NIW, but was not detected at 6 or 8 months.  A second NIW occurred in February 2011, and OPV was detected in the sewage collections 2 weeks and 5 weeks later.  The OPV detected was  primarily serotype 2.  At 3, 4, and 5 months, OPV serotypes predominantly contained the VAPP point mutations in the 5’ untranslated region associated with increased neurovirulence, at 7 months they predominantly did not contain the VAPP point mutations, and at 2 and 5 weeks after the second NIW, mixed mutant and non-mutant OPV serotypes were detected.

    Conclusion: OPV, primarily serotype 2, was detected in sewage as late as 7 months after an NIW in a Mexican community primarily vaccinated with IPV, but was not detected at 8 months, suggesting that OPV circulation may have ceased.  VAPP mutants were predominantly detected.  This data suggests that in communities with high vaccination rates, one or two years of IPV administration after OPV cessation could be sufficient to prevent outbreaks of paralytic poliomyelitis from vaccine-derived strains. 

    Supported by the World Health Organization and INSP.


    Subject Category: I. Adult and Pediatric Vaccines

    Stephanie Troy, MD1, Leticia Ferreyra-Reyes, MD2, Sergio Canizales-Quintero2, ChunHong Huang, MS1, Yu-Jin Lee1, Renata Báez-Saldaña, MD2, Elizabeth Ferreira-Guerrero, MD2, Lourdes García-García, MD2 and Yvonne Maldonado, MD1, (1)Stanford University School of Medicine, Stanford, CA, (2)Instituto Nacional de Salud Pública, Cuernavaca, Mexico

    Disclosures:

    S. Troy, None

    L. Ferreyra-Reyes, None

    S. Canizales-Quintero, None

    C. Huang, None

    Y. J. Lee, None

    R. Báez-Saldaña, None

    E. Ferreira-Guerrero, None

    L. García-García, None

    Y. Maldonado, Novartis: Vaccine Advisory Board, honorarium
    Merck: Vaccine Advisory Board, honorarium

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