PLoS One
http://www.plosone.org/
[Accessed 5 March 2016]

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The Success of a Universal Hepatitis B Immunization Program as Part of Thailand’s EPI after 22 Years’ Implementation
Nawarat Posuwan, Nasamon Wanlapakorn, Pattaratida Sa-nguanmoo, Rujipat Wasitthankasem, Preeyaporn Vichaiwattana, Sirapa Klinfueng, Viboonsak Vuthitanachot, Siriporn Sae-lao, Monthana Foonoi, Apinya Fakthongyoo, Jamorn Makaroon, Klaita Srisingh, Duangporn Asawarachun, Somchai Owatanapanich, Norra Wutthiratkowit, Kraisorn Tohtubtiang, Pornsak Yoocharoen, Sompong Vongpunsawad, Yong Poovorawan
Research Article | published 03 Mar 2016 | PLOS ONE
10.1371/journal.pone.0150499

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Immunization Coverage Surveys and Linked Biomarker Serosurveys in Three Regions in Ethiopia
Mark A. Travassos, Berhane Beyene, Zenaw Adam, James D. Campbell, Nigisti Mulholland, Seydou S. Diarra, Tassew Kassa, Lisa Oot, Jenny Sequeira, Mardi Reymann, William C. Blackwelder, Yukun Wu, Inna Ruslanova, Jaya Goswami, Samba O. Sow, Marcela F. Pasetti, Robert Steinglass, Amha Kebede, Myron M. Levine
Research Article | published 02 Mar 2016 | PLOS ONE
10.1371/journal.pone.0149970
Abstract
Objective
Demographic and health surveys, immunization coverage surveys and administrative data often divergently estimate vaccination coverage, which hinders pinpointing districts where immunization services require strengthening. We assayed vaccination coverage in three regions in Ethiopia by coverage surveys and linked serosurveys.
Methods
Households with children aged 12–23 (N = 300) or 6–8 months (N = 100) in each of three districts (woredas) were randomly selected for immunization coverage surveys (inspection of vaccination cards and immunization clinic records and maternal recall) and linked serosurveys. IgG-ELISA serologic biomarkers included tetanus antitoxin ≥ 0.15 IU/ml in toddlers (receipt of tetanus toxoid) and Haemophilus influenzae type b (Hib) anti-capsular titers ≥ 1.0 mcg/ml in infants (timely receipt of Hib vaccine).
Findings
Coverage surveys enrolled 1,181 children across three woredas; 1,023 (87%) also enrolled in linked serosurveys. Administrative data over-estimated coverage compared to surveys, while maternal recall was unreliable. Serologic biomarkers documented a hierarchy among the districts. Biomarker measurement in infants provided insight on timeliness of vaccination not deducible from toddler results.
Conclusion
Neither administrative projections, vaccination card or EPI register inspections, nor parental recall, substitute for objective serological biomarker measurement. Including infants in serosurveys informs on vaccination timeliness.