Transmission of the severe acute respiratory syndrome on aircraft.
BACKGROUND
The severe acute respiratory syndrome (SARS) spread rapidly around the world, largely because persons infected with the SARS-associated coronavirus (SARS-CoV) traveled on aircraft to distant cities. Although many infected persons traveled on commercial aircraft, the risk, if any, of in-flight transmission is unknown.


METHODS
We attempted to interview passengers and crew members at least 10 days after they had taken one of three flights that transported a patient or patients with SARS. All index patients met the criteria of the World Health Organization for a probable case of SARS, and index or secondary cases were confirmed to be positive for SARS-CoV on reverse-transcriptase polymerase chain reaction or serologic testing.


RESULTS
After one flight carrying a symptomatic person and 119 other persons, laboratory-confirmed SARS developed in 16 persons, 2 others were given diagnoses of probable SARS, and 4 were reported to have SARS but could not be interviewed. Among the 22 persons with illness, the mean time from the flight to the onset of symptoms was four days (range, two to eight), and there were no recognized exposures to patients with SARS before or after the flight. Illness in passengers was related to the physical proximity to the index patient, with illness reported in 8 of the 23 persons who were seated in the three rows in front of the index patient, as compared with 10 of the 88 persons who were seated elsewhere (relative risk, 3.1; 95 percent confidence interval, 1.4 to 6.9). In contrast, another flight carrying four symptomatic persons resulted in transmission to at most one other person, and no illness was documented in passengers on the flight that carried a person who had presymptomatic SARS.


CONCLUSIONS
Transmission of SARS may occur on an aircraft when infected persons fly during the symptomatic phase of illness. Measures to reduce the risk of transmission are warranted.
Olsen
Sonja J
SJ
International Emerging Infections Program, Centers for Disease Control and Prevention, Nonthaburi, Thailand. sco2@cdc.gov
Chang
Hsiao-Ling
HL
Cheung
Terence Yung-Yan
TY
Tang
Antony Fai-Yu
AF
Fisk
Tamara L
TL
Ooi
Steven Peng-Lim
SP
Kuo
Hung-Wei
HW
Jiang
Donald Dah-Shyong
DD
Chen
Kow-Tong
KT
Lando
Jim
J
Hsu
Kwo-Hsiung
KH
Chen
Tzay-Jinn
TJ
Dowell
Scott F
SF
D000368:Aged; D000401:Aircraft; D018562:Disease Transmission, Infectious; D004781:Environmental Exposure; D006723:Hong Kong; D006801:Humans; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D045169:Severe Acute Respiratory Syndrome / Q000635:transmission*; D014195:Travel