COMPARATIVE ESTIMATES OF CRUDE AND EFFECTIVE COVERAGE OF MEASLES IMMUNIZATION IN LOW-RESOURCE SETTINGS: FINDINGS FROM SALUD MESOAMÉRICA 2015

Thursday, 2nd of July 2015

COMPARATIVE ESTIMATES OF CRUDE AND EFFECTIVE COVERAGE OF MEASLES IMMUNIZATION IN LOW-RESOURCE SETTINGS: FINDINGS FROM SALUD MESOAMÉRICA 2015.

Full Article web page; http://www.ncbi.nlm.nih.gov/pubmed/26136239

 

Colson KE1, Zúñiga-Brenes P2, Ríos-Zertuche D2, Conde-Glez CJ3, Gagnier MC4, Palmisano E4, Ranganathan D5, Usmanova G4, Salvatierra B6, Nazar A6, Tristao I2, Sanchez Monin E2, Anderson BW7, Haakenstad A4, Murphy T8, Lim S4, Hernandez B4, Lozano R9, Iriarte E2, Mokdad AH4.

Author information

1Division of Epidemiology, University of California, Berkeley, California, United States of America.

2Salud Mesoamérica 2015/Inter-American Development Bank, Panama City, Panama.

3Instituto Nacional de Salud Pública, Cuernavaca, Mexico.

4Institute for Health Metrics and Evaluation, University of Washington, Seattle, Washington, United States of America.

5George Washington University, Washington, District of Columbia, United States of America.

6El Colegio de la Frontera Sur-Mexico, San Cristóbal de Las Casas, Chiapas, Mexico.

7County of Napa Health and Human Services, Department of Public Health, Napa, California, United States of America.

8School of Social Work, University of Washington, Seattle, Washington, United States of America.

9Institute for Health Metrics and Evaluation, University of Washington, Seattle, Washington, United States of America; Instituto Nacional de Salud Pública, Cuernavaca, Mexico.

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.