Two passengers taking a 10-hour flight from Dubai to Australia in July 2020 infected 15 other people, despite masking requirements for travellers, functioning air purifiers, and use of masks, eye goggles, gloves and protective gowns by the flight crew, according to a report in the Journal of Travel Medicine.
Being seated within two rows of a primary case increased the risk of infection more than seven-fold, and spending more than an hour in the arrival airport increased it nearly five-fold, the study found.
Seven of those who caught the virus were seated within 2 rows of the "index cases" in the economy section, but the others were seated far away, including some who were seated in business class.
At the time, all passengers entering Australia were required to submit to hotel quarantine and to provide blood samples for COVID-19 tests. Virus particles from the two originally infected travellers and the 15 newly-infected passengers had indistinguishable genomic sequences, according to the report.
"Conscientious mask wearing during travel reduced the risk of acquiring infection," particularly for passengers seated nearby, the researchers said. "With the emergence of more transmissible SARS-CoV-2 variants... it is crucial to understand and mitigate potential risk exposures associated with all stages of air travel."