To the Editor We are deeply disturbed by the Research Letter written by Majumder et al.1 The authors estimated that the measles, mumps, and rubella vaccination rate is as low as 50% and likely no higher than 86%. The estimation was based on the incidence decay and exponential adjustment model. The incidence decay and exponential adjustment model was developed by Fisman et al2 for rapid assessments of outbreak growth and public health intervention and has not been validated in small outbreaks. It is absurd to use a new unproven model to invalidate established data from a national survey.3 A more appropriate conclusion should be that because the estimated figure is different from the established data, the use of the incidence decay and exponential adjustment model to derive the effective reproductive number may not be valid in an outbreak of smaller numbers, such as the measles outbreak in United States.
Leung R, Munoz M. Vaccination Compliance and the US Measles Epidemic. JAMA Pediatr. 2015;169(9):876-877. doi:10.1001/jamapediatrics.2015.1530