Agent-Based Modelling Analysis of the 2019 New York City Measles Outbreak: Were Our Response Choices Effective?

Abstract

Measles outbreaks continue to occur in the developed world despite the wide availability and use of the Measles, Mumps, and Rubella (MMR) vaccine. Current research suggests that the growing trend of vaccine hesitancy contributes to the formation clusters of under-immunized individuals, which facilitate rampant outbreaks within these communities. One such cluster, the Haredi (ultra-orthodox) Jewish community in New York City, was the epicenter of the 2019 United States measles, the worst outbreak of the disease in the country since 1992. Two mandatory vaccination orders were imposed by government public health officials to end the outbreak. This study investigates the efficacy of these orders on curtailing the outbreak within the Haredi community, and assesses the role high initial vaccination coverage could have had on preventing the outbreak. An agent-based model was constructed specifically taking into account the community’s unique attributes and patterns of behavior that contribute to the high rates of vaccine hesitancy. Outbreak simulations were conducted to model “full,” “partial,” and “no” outbreak response, as well as varying levels of initial vaccination coverage. Results indicate that aggressive, early, implementation of outbreak responses are most effective at curtailing an outbreak within under-immunized communities. Moreover, maintaining a level of high vaccination coverage could thwart outbreaks altogether. Until under-immunized clusters are addressed, global eradication cannot occur, leaving nations vulnerable to imported measles cases that will continue to ignite rapid outbreaks by way of these clusters. These findings underscore the importance of tailoring public health responses to address individual differences across under-immunized clusters.