Estimation of measles reproduction ratios and prospects for elimination ofmeasles by vaccination in some Western European countries

The objective of this study is to estimate the measles reproduction ratio f or eight Western European vaccination programmes. Because many plausible ag e-structured transmission patterns result in a similar description of the o bservations, it is not possible to estimate a unique value of the reproduct ion ratio. A method is developed to estimate bounds and confidence interval s for plausible values of the reproduction ratios using maximum likelihood methods. Lower and upper bounds for plausible values of the basic reproduct ion ratio are estimated to be 7.17 (95% CI 7.14-7.20) and 45.41 (95% CI 9.7 7-49.57), corresponding to lower and upper bounds on critical vaccine cover age of 86.6% and 98.1%. Of the eight evaluated vaccination programmes, four have vaccine coverage below the lower bound and allow measles to persist, and four have vaccine coverage at the upper bound and may eventually elimin ate measles.