Transmission of Mycobacterium tuberculosis associated with air travel

Abstract

Objective: To investigate potential transmission of Mycobacterium tuberculosis in aircraft from a crew member with tuberculosis.

Design: Retrospective cohort study and survey.

Setting: A large US airline carrier.

Participants: A total of 212 crew members and 59 passengers who were exposed to a crew member with tuberculosis during a potentially infectious period (May through October 1992). Comparison volunteer sample of 247 unexposed crew members.

Main outcome measures: Positive tuberculin skin test (TST) result or tuberculosis.

Results: Rates of positive TST results were higher among foreign-born persons in all study groups. Among US-born comparisons and contacts, rates of positive TST results did not differ between comparisons and contacts exposed from May through July (5.3% vs 5.9%, respectively). However, contacts exposed from August through October had significantly higher rates of positive TST results than did contacts exposed from May through July (30% vs 5.8%, respectively; P < .001); two had documented TST conversions between September 1992 and February 1993. The risk of infection increased with increasing hours of exposure to the index case. Four (6.7%) of 59 frequent flyers were TST-positive; all flew in October.

Conclusions: Data support the conclusion that M tuberculosis was transmitted from an infectious crew member to other crew members on an aircraft. Because of the clustering of TST-positive frequent flyers in October when the index patient was most infectious, transmission of M tuberculosis to passengers cannot be excluded.