Omicron could at least double the risk of catching COVID-19 on a flight, airline industry medical expert says

• Omicron could at least double the risk of catching COVID-19 on a flight, an expert told Bloomberg.
• The IATA's medical advisor said Omicron could present two to three times the infection risk of Delta.

Omicron could double the risk of catching COVID-19 during a flight according to an airline industry medical expert, who warned that the airport carries a higher likelihood that the virus could spread than on the airplane itself.

The highly transmissible Omicron variant has been confirmed in more than 100 countries and has quickly become the most common cause of new COVID-19 cases in the US and South Africa.

"Whatever the risk was with Delta, we would have to assume the risk would be two to three times greater with Omicron, just as we've seen in other environments," Dr. David Powell, medical advisor at the International Air Transport Association, told Bloomberg Tuesday.

"The relative risk has probably increased, just as the relative risk of going to the supermarket or catching a bus has increased with Omicron," Powell added.

Powell said that the risk of catching COVID-19 caused by the Delta variant on a flight had been "low," though the exact level of that possibility had been unclear. Most of the data about the transmission of the virus on aircrafts was from March 2020 before there was easily available testing, masks, organized boarding procedures, and a high degree of awareness about not flying if you were unwell, he said.

Powell told Bloomberg that the requirements for air flows on board a plane — which tend to have exceptionally good ventilation systems — were generally "much more stringent" than they were for airports.

In an airport, he said, "There's much more random movement, much more potential for face-to-face contact, you've got generally reduced air flows." He estimated that airport ventilation rates were about a tenth of what they are during a flight.

Sheldon H. Jacobson, a professor of computer science at the University of Illinois who studies public health and aviation security, also recently warned that the "riskiest" part of air travel was the time before and after flights.

"Waiting in a terminal prior to boarding is a vulnerable time and environment for virus spread," he told CNBC Tuesday.

The Omicron variant has 32 mutations in the part of the virus that infect human cells, and has spread fast in several countries including the US, South Africa, Denmark, and the UK. In the US, Omicron went from making up 0.7% of COVID-19 cases to 73% of cases in just two weeks. It has now overtaken the highly infectious Delta variant to become the most common cause of new infections in the US, The Centers for Disease Control and Prevention (CDC) said Monday.

Experts advise travellers to mask up, wash hands frequently, and get vaccinated

Powell said that the advice remains the same to protect against Omicron as Delta: Wear a mask, wash hands frequently, use alcohol-based hand sanitizer, avoid common-touch surfaces, and get vaccinated or boosted, he said in a separate Bloomberg interview.

Powell said the biggest risk on an airplane itself is sitting next to someone who is ill. If you find yourself close to somebody who is obviously unwell, let the cabin crew know, he advised.

Dr. Anthony Fauci, President Biden's chief medical advisor, told NBC News Sunday that if "you're vaccinated, and you're boosted and you take care when you go into congregate setting like airports to continually wear your mask, you should be OK."

There is "no doubt" there are going to be breakthrough infections, Fauci cautioned. But there was a "major difference" with regard to the risk of getting severe COVID-19 between a vaccinated and boosted person and someone who has never been vaccinated. About 27% of Americans are unvaccinated, CDC data shows.

The CDC recommends against any travel if:

• You've been exposed to COVID-19 (unless fully vaccinated or a previous infection in the past 90 days)
• You're sick
• You're isolating for COVID-19
• You're awaiting test results.