HealthMap has been tracking news of a measles outbreak in Indiana following the state’s hosting of the Super Bowl on February 5. The latest case count is 16.
The story of the outbreak began with a couple traveling abroad where they were exposed to measles. The trip abroad is an important link in the exposure chain because measles is considered eliminated in the United States; this means any outbreaks in the U.S. originate with an imported case.
On Friday, February 3, the exposed (but not yet symptomatic) persons attended the festivities at the Super Bowl Village. Authorities estimated 200,000 people were in attendance, and thus at risk of possible exposure.
The first two cases was reported to county and state health departments sometime between February 3 and February 7, when the Indiana State Department of Health announced to the media the possibility of measles exposure. The state coordinated with local county health departments, the Centers for Disease Control, and health departments in Massachusetts and New York, the home states of the 2012 Super Bowl teams, to investigate the outbreak.
Of the initial two confirmed cases, only one person had attended the Super Bowl. Several days later, the original case’s companion was also confirmed to have measles. However, the two were believed to be together the entire time period they spent at the Super Bowl Village, and thus represent “one potential track exposure.” By February 13, Indiana had identified 10 confirmed cases, and noted that eight of these were members of the same social group, pointing to the extremely contagious nature of the disease.
On February 14, the case count was increased to 13; however, authorities had not yet identified any cases that arose from exposure via the Super Bowl. All cases were from Hamilton or Boone County, north of Indianapolis, and exposures had mainly occurred in local schools, stores, churches, and healthcare clinics. No cases have yet surfaced in Massachusetts or New York.
Additional cases in central Indiana were announced on February 18, 21, and 24, with the most recent count at 16 cases.
Measles is a highly contagious viral disease. It is a leading cause of death in young children across the world, but has been largely controlled in the developed world since the 1980s through vaccination. Sadly, vaccination rates have been declining in recent years, leading to an increased number of outbreaks in the United States, as covered in the Disease Daily.
The potential for disease spread is very real at a large sporting event like the Super Bowl. HealthMap has tracked infectious disease for mass gatherings like the 2011 Rugby World Cup or the Hajj. Please refer to the Disease Daily’s series on Mass Gathering and Infectious Disease for more information.