Epidemiology and Infection



Epidemiology of measles in Blantyre, Malawi: analyses of passive surveillance data from 1996 to 1998


S.  YAMAGUCHI  a1 a3 , A.  DUNGA  a2 , R. L.  BROADHEAD  a2 and B. J.  BRABIN  a3 a4 c1
a1 JICA/NMIMR Infectious Diseases Project, Noguchi Memorial Institute for Medical Research, University of Ghana
a2 Department of Paediatrics, College of Medicine, University of Malawi
a3 Tropical Child Health Group, Liverpool School of Tropical Medicine, Liverpool, UK
a4 Emma Kinderziekenhuis, Academic Medical Center, University of Amsterdam, The Netherlands

Abstract

Measles surveillance data in Blantyre, Malawi were reviewed for 1996–8 to describe the epidemiology of infection and to estimate vaccine efficacy (VE) by the screening method. A total of 674 measles cases were reported to the Blantyre District Health Office during this period. Age distribution showed that 108 (16.1%) of the cases were aged less than 1 year. The median age was 5 years. Eighty percent of the cases between 1 and 19 years had been previously vaccinated. VE was 68.6% (95% CI, 52.7–79.2) for children 12–23 months of age and 67.3% (95% CI, 48.3–79.3) for infants 9–11 months of age. Reasons for this low vaccine efficacy are discussed. Previous vaccination history was negatively associated with the risk for developing cough during measles infection (odds ratio (OR), 0.30; 95% CI, 0.09–0.91), diarrhoea (OR, 0.64; CI, 0.44–0.95) and pneumonia (OR, 0.40; CI, 0.25–0.62). Logistic regression analysis showed that pneumonia in adults was negatively associated with vaccination history. The passive surveillance system for measles in Malawi was useful to describe the epidemiology of measles.

(Accepted May 16 2002)


Correspondence:
c1 Author for correspondence: Tropical Child Health Group, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK.


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