Assessment of the status of measles elimination from reported outbreaks: United States, 1997-1999

Abstract

The status of measles elimination is best summarized by evaluation of the effective reproduction number R; maintaining R1 case. One hundred seven cases were classified as importations. All 3 methods suggested that R was in the range 0.6-0.7. Results were not sensitive to the minimum size and duration of outbreak considered (so long as single-case chains were excluded) or to exclusion of chains without a known imported source. These results demonstrate that susceptibility to measles was beneath the epidemic threshold and that endemic transmission was eliminated