Population impact and effectiveness of monovalent rotavirus vaccination in urban Malawian children 3 years after vaccine introduction: ecological and case-control analyses

Bar-Zeev, N. et al. (2016) Population impact and effectiveness of monovalent rotavirus vaccination in urban Malawian children 3 years after vaccine introduction: ecological and case-control analyses. Clinical Infectious Diseases, 62(suppl2), S213-S219. (doi: 10.1093/cid/civ1183) (PMID:27059359) (PMCID:PMC4825885)

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Background. Rotavirus vaccines have been introduced in many low-income African countries including Malawi in 2012. Despite early evidence of vaccine impact, determining persistence of protection beyond infancy, the utility of the vaccine against specific rotavirus genotypes, and effectiveness in vulnerable subgroups is important. Methods. We compared rotavirus prevalence in diarrheal stool and hospitalization incidence before and following rotavirus vaccine introduction in Malawi. Using case-control analysis, we derived vaccine effectiveness (VE) in the second year of life and for human immunodeficiency virus (HIV)–exposed and stunted children. Results. Rotavirus prevalence declined concurrent with increasing vaccine coverage, and in 2015 was 24% compared with prevaccine mean baseline in 1997–2011 of 32%. Since vaccine introduction, population rotavirus hospitalization incidence declined in infants by 54.2% (95% confidence interval [CI], 32.8–68.8), but did not fall in older children. Comparing 241 rotavirus cases with 692 test-negative controls, VE was 70.6% (95% CI, 33.6%–87.0%) and 31.7% (95% CI, −140.6% to 80.6%) in the first and second year of life, respectively, whereas mean age of rotavirus cases increased from 9.3 to 11.8 months. Despite higher VE against G1P[8] than against other genotypes, no resurgence of nonvaccine genotypes has occurred. VE did not differ significantly by nutritional status (78.1% [95% CI, 5.6%–94.9%] in 257 well-nourished and 27.8% [95% CI, −99.5% to 73.9%] in 205 stunted children; P = .12), or by HIV exposure (60.5% [95% CI, 13.3%–82.0%] in 745 HIV-unexposed and 42.2% [95% CI, −106.9% to 83.8%] in 174 exposed children; P = .91). Conclusions. Rotavirus vaccination in Malawi has resulted in reductions in disease burden in infants <12 months, but not in older children. Despite differences in genotype-specific VE, no genotype has emerged to suggest vaccine escape. VE was not demonstrably affected by HIV exposure or stunting.

Item Type:Articles
Additional Information:This work was supported by the Wellcome Trust (programme grant number 091909/Z/10/Z and the MLW Programme Core Award). Rotavirus genotyping was partially supported by a research grant from GlaxoSmithKline Biologicals. A. B. and L. P. are supported by Wellcome Trust Clinical PhD fellowships.
Glasgow Author(s) Enlighten ID:Crampin, Professor Mia
Authors: Bar-Zeev, N., Jere, K. C., Bennett, A., Pollock, L., Tate, J. E., Nakagomi, O., Iturriza-Gomara, M., Costello, A., Mwansambo, C., Parashar, U. D., Heyderman, R. S., French, N., Cunliffe, N. A., Beard, J., Crampin, A. C., King, C., Lewycka, S., Mvula, H., Phiri, T., Verani, J. R., and Whitney, C. G.
College/School:College of Medical Veterinary and Life Sciences > Institute of Health and Wellbeing > Public Health
Journal Name:Clinical Infectious Diseases
Publisher:Oxford University Press
ISSN (Online):1537-6591
Published Online:07 April 2016
Copyright Holders:Copyright © 2016 The Authors
First Published:First published in Clinical Infectious Diseases 62(suppl2):S213-S219
Publisher Policy:Reproduced under a Creative Commons License

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