Transmission of Mycobacterium tuberculosis associated with air travel.

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.