Tuberculosis investigations associated with air travel: U. S. Centers for Disease Control and Prevention, January 2007-June 2008.
BACKGROUND
Contact investigations conducted in the United States of persons with tuberculosis (TB) who traveled by air while infectious have increased. However, data about transmission risks of Mycobacterium tuberculosis on aircraft are limited.


METHODS
We analyzed data on index TB cases and passenger contacts from contact investigations initiated by the U.S. Centers for Disease Control and Prevention from January 2007 through June 2008.


RESULTS
Contact investigations for 131 index cases met study inclusion criteria, including 4550 passenger contacts. U.S. health departments reported TB screening test results for 758 (22%) of assigned contacts; 182 (24%) had positive results. Of the 142 passenger contacts with positive TB test results with information about risk factors for prior TB infection, 130 (92%) had at least one risk factor and 12 (8%) had no risk factors. Positive TB test results were significantly associated with risk factors for prior TB infection (OR 23; p<0.001). No cases of TB disease among passenger contacts were reported.


CONCLUSIONS
The risks of M. tuberculosis transmission during air travel remain difficult to quantify. Definitive assessment of transmission risks during flights and determination of the effectiveness of contact-tracing efforts will require comprehensive cohort studies.
Marienau
Karen J
KJ
Centers for Disease Control and Prevention, National Center for Preparedness, Detection, and Control of Infectious Diseases, Division of Global Migration and Quarantine, Atlanta, GA, USA. kqm5@cdc.gov <kqm5@cdc.gov>
Burgess
Gregory W
GW
Cramer
Elaine
E
Averhoff
Francisco M
FM
Buff
Ann M
AM
Russell
Michelle
M
Kim
Curi
C
Neatherlin
John C
JC
Lipman
Harvey
H
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000401:Aircraft; D002487:Centers for Disease Control and Prevention, U.S. / Q000706:statistics & numerical data*; D016358:Contact Tracing / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009169:Mycobacterium tuberculosis; D012307:Risk Factors; D013183:Sputum / Q000382:microbiology; D014195:Travel; D014374:Tuberculin Test; D014376:Tuberculosis / Q000453:epidemiology / Q000382:microbiology / Q000517:prevention & control / Q000635:transmission*; D014481:United States; D055815:Young Adult