Contact tracing of in-flight measles exposures: lessons from an outbreak investigation and case series, Australia, 2010

Abstract

Objective: To describe a 2010 outbreak of nine cases of measles in Australia possibly linked to an index case who travelled on an international flight from South Africa while infectious.

Methods: Three Australian state health departments, Victoria, Queensland and New South Wales, were responsible for the investigation and management of this outbreak, following Australian public health guidelines.

Results: An outbreak of measles occurred in Australia after an infectious case arrived on a 12-hour flight from South Africa. Only one of four cases in the first generation exposed to the index case en route was sitting within the two rows recommended for contact tracing in Australian and other guidelines. The remaining four cases in subsequent generations, including two health care workers, were acquired in health care settings. Seven cases were young adults. Delays in diagnosis and notification hampered disease control and contact tracing efforts.

Conclusion: Review of current contact tracing guidelines following in-flight exposure to an infectious measles case is required. Alternative strategies could include expanding routine contact tracing beyond the two rows on either side of the case’s row or expansion on a case-by-case basis depending on cabin layout and case and contact movements in flight. Releasing information about the incident by press release or providing generic information to everyone on the flight using e-mail or text messaging information obtained from the relevant airline, may also be worthy of consideration. Disease importation, inadequately vaccinated young adults and health care-related transmission remain challenges for measles control in an elimination era.