Status of Measles Elimination from the Reported Outbreaks: Fars Province, 2001–03

Background: The status of measles elimination is best summarized by evaluation of the effective reproduction number R; maintaining R < 1 is necessary and sufficient to achieve elimination. In the present article, we estimated reproduction number  for the measles data reported for the Fars province of Iran in 2001–03. Methods: We estimated by using sizes and durations of chains of measles transmission and the proportion of cases imported, when offspring distribution is either Poisson or geometric. In each case, we calculated the profile 95% confidence intervals. These comprised 575 cases, forming 191 chains of transmission, of which 79 had > 1 case. 128 cases were classified as importations. Results: The results using the Poisson and geometric distribution for offspring and the proportion of cases imported differed slightly, but all 3 methods gave an  < 1. The results were not sensitive to the minimum size and duration of outbreak considered, as long as single-case chains were excluded, or to exclusion of chains without a known important source. Conclusion: These results demonstrated that susceptibility to measles was beneath the epidemic threshold and that endemic transmission was eliminated.