1626. Towards Polio Eradication: OPV and IPV exposure in Mexican Communities Preparing for a Randomized Controlled Trial of Poliovirus Circulation Patterns
Session: Poster Abstract Session: Global Health
Saturday, October 10, 2015
Room: Poster Hall
Posters
  • IDSA_polio_2015 Final.pdf (1.4 MB)
  • Background: Oral Polio Vaccine (OPV) can mutate and cause paralytic polio. The World Health Assembly’s 2012 Polio Eradication and Endgame Strategic Plan replaces OPV with Injected Polio Vaccine (IPV).  There will be overlap in each vaccine’s use in most countries.  It is unclear how using a combination of IPV and OPV will affect OPV shedding and circulation. Mexico is a natural laboratory as it has both routine IPV vaccination and twice annual OPV vaccination.  To elucidate inter- and intra-household transmissibility and persistence of OPV following vaccination, we are performing a large-scale randomized controlled trial (RCT) in three communities in Mexico. 

    Methods: The study began with a census of all households in the communities to: (1) understand adherence to national vaccination policy in this semi-urban area, (2) determine RCT participation eligibility, and (3) allow comparisons between the study population and general population. Census results are described below.

    Results: Mexico’s routine immunization schedule includes 4 doses of pentavalent vaccine (including IPV) in the first 2 years of life. There were 596 children between 2-5 in this population, and 918 children <5 overall. 181/261 (69.3%) of the children 2-5 not enrolled in the study and 234/335 (69.9%) of the enrolled children 2-5 completed all 4 doses of the pentavalent vaccine (p=0.93). Previous OPV exposure was also collected, and 365/485 (75.2%) of the study participants and 275/433 (63.5%) of the non-participants had previously received at least one dose (p=0.0001).

    Conclusion: Compliance with the national immunization policy for the pentavalent vaccine was lower than expected (~70%). Previous exposure to IPV was similar, but previous OPV exposure differed, in the study population compared to the general population of these communities. In order to improve vaccination rates in these communities, families with incomplete vaccine adherence were referred, and in some cases transported, to local healthcare centers. In order to further understand OPV receipt and adherence to the study randomization, surveys regarding OPV exposure during the study period are being carried out. In addition, implications of these findings for epidemiological and analytic approaches to the data will be discussed.

    Clea Sarnquist, DrPh, MPH1, Marisa Holubar, MD1, Lourdes Garcia-Garcia, MD2, Leticia Ferreyra Reyes, MD2, Rogelio Montero-Campos, MS2, Luis Pablo Cruz-Hervert, MSc2, Aisha Talib, MPP3, Meira Falkovitz Halpern, PhD3 and Yvonne Maldonado, MD, FIDSA, FPIDS1, (1)Pediatrics, Stanford University School of Medicine, Stanford, CA, (2)Instituto Nacional de Salud Pública, Cuernavaca, Mexico, (3)Stanford University, Stanford, CA

    Disclosures:

    C. Sarnquist, None

    M. Holubar, None

    L. Garcia-Garcia, None

    L. Ferreyra Reyes, None

    R. Montero-Campos, None

    L. P. Cruz-Hervert, None

    A. Talib, None

    M. Falkovitz Halpern, None

    Y. Maldonado, None

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