Risk of contracting Covid-19 on flights less than 0.1 per cent

Person on a flight

The risk of exposure to Covid-19 while travelling after all passengers test negative 72 hours in advance of a flight is less than 0.1 per cent, according to a study of data on Delta flights

The peer-reviewed study published in Mayo Clinic Proceedings showed a single Covid-19 molecular test performed within 72 hours of departure could decrease the rate of people actively infected onboard a commercial aircraft to a level that is significantly below active community infection rates. For example, when the average community infection rate was at 1.1 per cent – or about one in 100 people – infection rates on Covid-19-tested flights were 0.05 per cent or five in 10,000 passengers. The Georgia Department of Health and Mayo Clinic conducted the study in conjunction with Delta.

“We are going to live with Covid-19 variants for some time,” explained Dr Henry Ting, Delta’s Chief Health Officer. “This real-world data is what governments around the world can use as a blueprint for requiring vaccinations and testing instead of quarantines to reopen borders for international travel.

“Air travel risk varies depending on case rates and vaccination rates at the origin and destination, masking and other factors. But the data collected from this study show that the routine use of a single molecular test within 72 hours before international travel for unvaccinated individuals significantly mitigates the risk of Covid-19 exposure and transmission during airline travel.”

Risk of transmission less than one in one million

The study began in December 2020 with the trans-Atlantic Covid-19 testing programme, which enabled quarantine-free entry into Italy and allowed teams to review and model various testing strategies for feasibility, false-positive rates, and case detection rates.

“When you couple the extremely low infection rate onboard a Covid-19-tested flight with the layers of protection onboard, including mandatory masking and hospital-grade air filtration, the risk of transmission is less than one in one million between the US and the UK, for example,” Dr Ting added. “These numbers will improve further as vaccination rates increase and new cases decrease worldwide.”

Meanwhile, the information that travellers and their risk managers need to seek out prior to their trips is becoming more complex, ITIJ recently reported.