A recent study from Australia published in the Journal of Travel Medicine has cautioned that air travelers are at risk of acquiring Covid-19 in the airplane as well as in the airports.¹

Researchers investigated suspected transmission of SARS-CoV-2 during a long flight coming into Australia from the UAE in July 2020, which had 95 passengers. From 6th August to 29th September 2020, the passengers were enquired about their searing, movement during the flight, country from where travel started, hand hygiene and use of masks during and after the flight.

Seventeen passengers from four different travel origins tested positive for the virus on RT PCR. Of these, two people who had travelled together from the same country, developed symptoms within two days and were categorized as co-primary cases. Seven passengers seated within two rows of the coprimary cases were infected and termed as secondary cases. However, three business class passengers and five in the economy seated at a distance from the primary cases also tested positive for the infection with a secondary attack rate of 16% (15/93).

Passengers who were seated within two rows of a primary case had 7-folds higher risk of infection with an odds ratio of 7.16. Those who stayed for longer than an hour in the airport after arrival during disembarkation procedures were also five times more at risk of being infected (OR 4.96).

This study has demonstrated high probability of in-flight transmission of SARS-CoV-2 particularly among travelers who were seated within two rows of the primary cases. This is also the standard followed for contact tracing of air travelers. Infection transmission was also likely at the airport before boarding the flight and also upon arrival. Wearing of masks during the flight was protective even for passengers seated within 2-rows of the primary cases. At the time this study was conducted, all air travelers had to undergo mandatory hotel quarantine and periodic testing for Covid-19. Emergence of immunoevasive highly transmissible variants underscores the significance of covid appropriate behaviors in protecting against infection. The study also highlights the need to minimize risk exposures during air travel - preboarding, during the flight and after disembarking.

Reference

1. Ngeh S, et al. Travel-associated SARS-CoV-2 transmission documented with whole genome sequencing following a long-haul international flight. J Travel Med. 2022 May 7;taac057. doi: 10.1093/jtm/taac057.