Evaluation of a measles vaccine campaign by oral-fluid surveys in a rural Kenyan district: interpretation of antibody prevalence data using mixture models
Ohuma, E. O.
Okiro, E. A.
Vyse, A. J.
Gay, N. J.
Brown, D. W. G.
Nokes, D. James
- Publisher: Cambridge University Press
Epidemiology and Infection,
(issn: 0950-2688, eissn: 1469-4409)
measles antibodies | Methods | mixture modelling | oral fluid | Campaign vaccination | Original Papers | Kenya | RA
SUMMARY We evaluated the effectiveness of a measles vaccine campaign in rural Kenya, based on oral-fluid surveys and mixture-modelling analysis. Specimens were collected from 886 children aged 9 months to 14 years pre-campaign and from a comparison sample of 598 children aged 6 months post-campaign. Quantitative measles-specific antibody data were obtained by commercial kit. The estimated proportions of measles-specific antibody negative in children aged 0–4, 5–9 and 10–14 years were 51%, 42% and 27%, respectively, pre- campaign and 18%, 14% and 6%, respectively, post-campaign. We estimate a reduction in the proportion susceptible of 65–78%, with ~85% of the population recorded to have received vaccine. The proportion of ‘weak’ positive individuals rose from 35% pre-campaign to 54% post-campaign. Our results confirm the effectiveness of the campaign in reducing susceptibility to measles and demonstrate the potential of oral-fluid studies to monitor the impact of measles vaccination campaigns.