title: Comparative Estimates of Crude and Effective Coverage of Measles Immunization in Low-Resource Settings: Findings from Salud Mesoamérica 2015.
abstract: Timely and accurate measurement of population protection against measles is critical for decision-making and prevention of outbreaks. However, little is known about how survey-based estimates of immunization (crude coverage) compare to the seroprevalence of antibodies (effective coverage), particularly in low-resource settings. In poor areas of Mexico and Nicaragua, we used household surveys to gather information on measles immunization from child health cards and caregiver recall. We also collected dried blood spots (DBS) from children aged 12 to 23 months to compare crude and effective coverage of measles immunization. We used survey-weighted logistic regression to identify individual, maternal, household, community, and health facility characteristics that predict gaps between crude coverage and effective coverage. We found that crude coverage was significantly higher than effective coverage (83% versus 68% in Mexico; 85% versus 50% in Nicaragua). A large proportion of children (19% in Mexico; 43% in Nicaragua) had health card documentation of measles immunization but lacked antibodies. These discrepancies varied from 0% to 100% across municipalities in each country. In multivariate analyses, card-positive children in Mexico were more likely to lack antibodies if they resided in urban areas or the jurisdiction of De Los Llanos. In contrast, card-positive children in Nicaragua were more likely to lack antibodies if they resided in rural areas or the North Atlantic region, had low weight-for-age, or attended health facilities with a greater number of refrigerators. Findings highlight that reliance on child health cards to measure population protection against measles is unwise. We call for the evaluation of immunization programs using serological methods, especially in poor areas where the cold chain is likely to be compromised. Identification of within-country variation in effective coverage of measles immunization will allow researchers and public health professionals to address challenges in current immunization programs.
authors.affiliation: Division of Epidemiology, University of California, Berkeley, California, United States of America.
authors.forename: K Ellicott
authors.initials: KE
authors.lastname: Colson
authors.affiliation: Salud Mesoamérica 2015/Inter-American Development Bank, Panama City, Panama.
authors.forename: Paola
authors.initials: P
authors.lastname: Zúñiga-Brenes
authors.affiliation: Salud Mesoamérica 2015/Inter-American Development Bank, Panama City, Panama.
authors.forename: Diego
authors.initials: D
authors.lastname: Ríos-Zertuche
authors.affiliation: Instituto Nacional de Salud Pública, Cuernavaca, Mexico.
authors.forename: Carlos J
authors.initials: CJ
authors.lastname: Conde-Glez
authors.affiliation: Institute for Health Metrics and Evaluation, University of Washington, Seattle, Washington, United States of America.
authors.forename: Marielle C
authors.initials: MC
authors.lastname: Gagnier
authors.affiliation: Institute for Health Metrics and Evaluation, University of Washington, Seattle, Washington, United States of America.
authors.forename: Erin
authors.initials: E
authors.lastname: Palmisano
authors.affiliation: George Washington University, Washington, District of Columbia, United States of America.
authors.forename: Dharani
authors.initials: D
authors.lastname: Ranganathan
authors.affiliation: Institute for Health Metrics and Evaluation, University of Washington, Seattle, Washington, United States of America.
authors.forename: Gulnoza
authors.initials: G
authors.lastname: Usmanova
authors.affiliation: El Colegio de la Frontera Sur-Mexico, San Cristóbal de Las Casas, Chiapas, Mexico.
authors.forename: Benito
authors.initials: B
authors.lastname: Salvatierra
authors.affiliation: El Colegio de la Frontera Sur-Mexico, San Cristóbal de Las Casas, Chiapas, Mexico.
authors.forename: Austreberta
authors.initials: A
authors.lastname: Nazar
authors.affiliation: Salud Mesoamérica 2015/Inter-American Development Bank, Panama City, Panama.
authors.forename: Ignez
authors.initials: I
authors.lastname: Tristao
authors.affiliation: Salud Mesoamérica 2015/Inter-American Development Bank, Panama City, Panama.
authors.forename: Emmanuelle
authors.initials: E
authors.lastname: Sanchez Monin
authors.affiliation: County of Napa Health and Human Services, Department of Public Health, Napa, California, United States of America.
authors.forename: Brent W
authors.initials: BW
authors.lastname: Anderson
authors.affiliation: Institute for Health Metrics and Evaluation, University of Washington, Seattle, Washington, United States of America.
authors.forename: Annie
authors.initials: A
authors.lastname: Haakenstad
authors.affiliation: School of Social Work, University of Washington, Seattle, Washington, United States of America.
authors.forename: Tasha
authors.initials: T
authors.lastname: Murphy
authors.affiliation: Institute for Health Metrics and Evaluation, University of Washington, Seattle, Washington, United States of America.
authors.forename: Stephen
authors.initials: S
authors.lastname: Lim
authors.affiliation: Institute for Health Metrics and Evaluation, University of Washington, Seattle, Washington, United States of America.
authors.forename: Bernardo
authors.initials: B
authors.lastname: Hernandez
authors.affiliation: Institute for Health Metrics and Evaluation, University of Washington, Seattle, Washington, United States of America; Instituto Nacional de Salud Pública, Cuernavaca, Mexico.
authors.forename: Rafael
authors.initials: R
authors.lastname: Lozano
authors.affiliation: Salud Mesoamérica 2015/Inter-American Development Bank, Panama City, Panama.
authors.forename: Emma
authors.initials: E
authors.lastname: Iriarte
authors.affiliation: Institute for Health Metrics and Evaluation, University of Washington, Seattle, Washington, United States of America.
authors.forename: Ali H
authors.initials: AH
authors.lastname: Mokdad
mesh_terms: D000293:Adolescent; D000328:Adult; D000914:Antibodies, Viral / Q000097:blood*; D002675:Child, Preschool; D003906:Developing Countries; D059788:Dried Blood Spot Testing; D004355:Drug Stability; D004356:Drug Storage; D005260:Female; D019538:Health Care Surveys / Q000706:statistics & numerical data; D055991:Health Records, Personal; D006801:Humans; D017589:Immunization Programs / Q000191:economics / Q000706:statistics & numerical data*; D007223:Infant; D008297:Male; D008457:Measles / Q000097:blood / Q000276:immunology / Q000517:prevention & control* / Q000821:virology; D008458:Measles Vaccine / Q000008:administration & dosage* / Q000191:economics / Q000600:supply & distribution; D008459:Measles virus / Q000276:immunology / Q000302:isolation & purification; D008800:Mexico; D008875:Middle Aged; D009527:Nicaragua; D014611:Vaccination / Q000295:instrumentation / Q000706:statistics & numerical data*
chemical_list: D000914:Antibodies, Viral; D008458:Measles Vaccine