After Action Review of the 2019 measles outbreak in Clark County, Washington, U.S.A

Issue Clark County experienced a measles outbreak that challenged public health authorities. Description of the practice: We conducted a formal After Action Review with state and local health officials, school officials, and others to identify lessons for public health practitioners facing future outbreaks. Results Following the early identification of measles in a child who had recently arrived from Ukraine, active surveillance identified 71 confirmed cases, most in unvaccinated persons under 18 years of age. 4,138 contacts were traced and public health personnel made daily monitoring calls to 816. 53 potential exposure sites in healthcare facilities, schools and other public places were identified and communicated to the public. As a social distancing measure, unvaccinated students, teachers, and staff were excluded from schools in which exposure had occurred. Ascertaining susceptibility status was challenging. The national anti-vaccination sentiment and a parallel outbreak in a New York religious community created challenges in representing community risk while avoiding stigmatization of a community in which the first reported case was identified. Rather than respond to every false claim on social media, the health department developed talking points about emerging issues and engaged the community in dialogue. Lessons Responding to the measles outbreak required innovative approaches to surveillance and contact tracing, social distancing (school exclusions), and emergency risk communication. The response required extensive coordinated efforts of the county and state health departments, school systems, and many other organizations. Mutual aid enabled an influx of resources but managing the surge of responders proved challenging. Key messages Public health emergencies require effective emergency management practices. Carefully conducted After Action Reviews of health emergencies can help public health practitioners identify challenges and innovative practices.