A Review of Reports to CDC of Travelers Who Flew While Infectious With Pertussis From April 2013 to February 2024

Context: Pertussis is endemic worldwide, and exposure can occur anywhere, including commercial aircraft. Travelers exposed to an infectious person with pertussis may receive post-exposure prophylaxis (PEP) for up to 21 days after exposure to decrease risk of infection. This is accomplished through the identification of infectious travelers and their aircraft contacts (a process called aircraft contact investigation [Air CIs]). Objective: Describe travelers reported to the US Centers for Disease Control and Prevention (CDC) who flew while infectious with pertussis and outcomes of associated Air CIs. Design: CDC’s Port Health Activity Reporting System (PHARS) was queried to identify reports of travelers who flew with pertussis from April 12, 2013, to February 28, 2024. Participants: Index cases (passengers or crew members) with pertussis who traveled on commercial aircraft and their exposed passenger contacts. Main Outcome Measure(s): Traveler demographics, flight characteristics, outcome data from Air CIs. Results: Three hundred and eight individuals who recently traveled on commercial aircraft with pertussis were identified. Of the passengers determined to be infectious on the flights, Air CIs were initiated for 102/270 (38%) travelers who flew on 163/500 (33%) flights. Among the 337/500 (67%) flights for which Air CI was not initiated, the most common reason was that the index case was seated adjacent to only household members (142/337, 42%). For flights in which Air CIs were initiated, 234 contacts were identified, and one secondary case in a non-household passenger contact was reported. The average time from when contacts were exposed during the flight to when a health department reported the index case to CDC was 11.6 days (median 10.3 days, range: 0-39 days). Conclusions: Timely reporting of pertussis cases after air travel may decrease transmission risk to passenger contacts and prevent severe illness.