TRANSPORT NETWORKS AND INEQUITIES IN VACCINATION: REMOTENESS SHAPES MEASLES VACCINE COVERAGE AND PROSPECTS FOR ELIMINATION ACROSS AFRICA

Sunday, 26th of April 2015

TRANSPORT NETWORKS AND INEQUITIES IN VACCINATION: REMOTENESS SHAPES MEASLES VACCINE COVERAGE AND PROSPECTS FOR ELIMINATION ACROSS AFRICA

C. J. E. METCALF^a1a2a3 c1, A. TATEM^a2a4a5, O. N. BJORNSTAD^a6, J. LESSLER^a7, K. OREILLY^a8, S. TAKAHASHI^a3, F. CUTTS^a9 and B.T. GRENFELL^a2a3

^a1 Department of Zoology, Oxford University, Oxford, UK

^a2 Fogarty International Center, National Institute of Health, Bethesda, MD, USA

^a3 Department of Ecology and Evolutionary Biology, Eno Hall, Princeton University, Princeton, NJ, USA

^a4 Department of Geography and Environment University of Southampton, Southampton, UK

^a5 Flowminder Foundation, Stockholm, Sweden

^a6 Centre for Infectious Disease Dynamics, The Pennsylvania State University, University Park, PA, USA

^a7 Department of Epidemiology, John Hopkins Bloomberg School of Public Health, Baltimore, MD, USA

^a8 Medical Research Council Centre for Outbreak Analysis and Modelling, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, London, UK

^a9 London School of Hygiene and Tropical Medicine, London, UK

Summary below; full text is at http://journals.cambridge.org/action/displayFulltext?type=6&fid=9635561&jid=HYG&volumeId=143&issueId=07&aid=9635560&bodyId=&membershipNumber=&societyETOCSession=&fulltextType=RA&fileId=S0950268814001988

Measles vaccination is estimated to have averted 13·8 million deaths between 2000 and 2012. Persisting heterogeneity in coverage is a major contributor to continued measles mortality, and a barrier to measles elimination and introduction of rubella-containing vaccine. Our objective is to identify determinants of inequities in coverage, and how vaccine delivery must change to achieve elimination goals, which is a focus of the WHO Decade of Vaccines. We combined estimates of travel time to the nearest urban centre (≥50 000 people) with vaccination data from Demographic Health Surveys to assess how remoteness affects coverage in 26 African countries. Building on a statistical mapping of coverage against age and geographical isolation, we quantified how modifying the rate and age range of vaccine delivery affects national coverage. Our scenario analysis considers increasing the rate of delivery of routine vaccination, increasing the target age range of routine vaccination, and enhanced delivery to remote areas. Geographical isolation plays a key role in defining vaccine inequity, with greater inequity in countries with lower measles vaccine coverage. Eliminating geographical inequities alone will not achieve thresholds for herd immunity, indicating that changes in delivery rate or age range of routine vaccination will be required. Measles vaccine coverage remains far below targets for herd immunity in many countries on the African continent and is likely to be inadequate for achieving rubella elimination. The impact of strategies such as increasing the upper age range eligible for routine vaccination should be considered.

(Received April 15 2014)

(Revised June 16 2014)

(Accepted July 16 2014)

(Online publication August 14 2014)

Correspondence

^c1 Author for correspondence: Dr C. J. E. Metcalf, Department of Ecology and Evolutionary Biology, Eno Hall, Princeton University, Princeton, NJ, USA. (Email: cmetcalf@princeton.edu)