Epidemiology and Infection

Table of Contents - July 2011 - Volume 139, Issue 07  

Childhood infections

Maintaining high rates of measles immunization in Africa

J. LESSLERa1 c1, W. J. MOSSa1, S. A. LOWTHERa1 and D. A. T. CUMMINGSa1

a1 Department of Epidemiology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA

SUMMARY

Supplementary immunization activities (SIAs) are important in achieving high levels of population immunity to measles virus. Using data from a 2006 survey of measles vaccination in Lusaka, Zambia, we developed a model to predict measles immunity following routine vaccination and SIAs, and absent natural infection. Projected population immunity was compared between the current programme and alternatives, including supplementing routine vaccination with a second dose, or SIAs at 1-, 2-, 3-, 4- and 5-year intervals. Current routine vaccination plus frequent SIAs could maintain high levels of population immunity in children aged <5 years, even if each frequent SIA has low coverage (e.g. ≥72% for bi-annual 60% coverage SIAs vs. ≥69% for quadrennial 95% coverage SIAs). A second dose at 12 months with current coverage could achieve 81% immunity. Circulating measles virus will only increase population immunity. Public health officials should consider frequent SIAs when resources for a two-dose strategy are unavailable.

(Accepted August 30 2010)

(Online publication October 05 2010)

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Correspondence:

c1 Author for correspondence: Dr J. Lessler, Johns Hopkins Bloomberg School of Public Health, Department of Epidemiology, 615 N. Wolfe St, Baltimore, MD 21224, USA. (Email: jlessler@jhsph.edu)

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