Variant may double risk of getting infected on planes: Iata

MONTREAL • Aircraft passengers are twice or even three times more likely to catch Covid-19 during a flight following the emergence of the Omicron variant, according to the top medical adviser to the world's airlines.

The new strain is highly transmissible and has become dominant in a matter of weeks, accounting for more than 70 per cent of all new cases in the United States alone.

While hospital-grade air filters on modern passenger jets make the risk of infection much lower on planes than in crowded places on the ground such as shopping malls, Omicron is rapidly spreading just as more travellers take to the skies for year-end holidays and family reunions.

Business class may be safer than more densely packed economy cabins, said Dr David Powell, a physician and medical adviser to the International Air Transport Association (Iata), which represents almost 300 carriers worldwide.

As before, passengers should avoid face-to-face contact and surfaces that are frequently touched, and people sitting near each other should try not to be unmasked at the same time during meals, he said.

"The relative risk has probably increased, just as the relative risk of going to the supermarket or catching a bus has increased," said Dr Powell, former chief medical officer of Air New Zealand, who was speaking to Bloomberg News on Tuesday about flying during the pandemic.

A 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 have seen in other environments. Whatever that low risk - we don't know what it is - on the airplane, it must be increased by a similar amount.

A Avoid common touch surfaces, hand hygiene wherever possible, masks, distancing, controlled boarding procedures, try to avoid face-to-face contact with other customers, try to avoid being unmasked in flight, for meal and drink services, apart from when really necessary.

The advice is the same; it is just that the relative risk has probably increased, just as the relative risk of going to the supermarket or catching a bus has increased with Omicron. For a two-hour flight, it is pretty easy to say, "Just keep your mask on the whole time". But if it is a 10-hour flight, it becomes pretty unreasonable to ask people not to eat and drink.

A The greatest protection you can give yourself is to be vaccinated and boosted. The protection that you give yourself from an extra mask or a different type of mask, or not flying at all, frankly, is probably less than the benefit you would get from just being fully boosted.

There is a sort of a rule of thumb starting to appear: Two doses against Omicron is about similar protection to one dose against Delta.

That is not established in hard science, but it roughly seems to correlate with what is coming out in studies.

A It is an enclosed space, but it is a leaky box, and we pressurise it by putting a huge airflow on one end of it, and then having an exhaust valve out the other end.

So, you are sitting in a very high-flow airflow environment.

An Irish pub with a fan in the corner shouts "risk" to me, or a gymnasium with a whole lot of people shouting and grunting and sweating.

But any flight you take does involve airports as well, which are a little bit less controlled. So, there is risk there.

A Vaccination, testing, mask-wearing, distancing.

Are surgical masks better than cloth masks? Yes, probably. On average, maybe 10 per cent to 20 per cent.

Having said all that, still, it has been our observation throughout the pandemic that airline flights have been less conducive to spread than other indoor environments.

Again, we are not saying perfect, but compared with restaurants, buses, subways, you know, nightclubs, gyms, all of those that have been studied. The likelihood of transferring to another person is less on an aeroplane.

Most of the documented cases of spread in flight are from way back in March 2020 - before we had testing, before we had masks, before we had organised boarding procedures, before there was a high degree of awareness about not flying if you were unwell.

A It is incredibly appealing, intuitively. It does give a greater physical distance between you and the next person. But we haven't seen that actually deliver a whole lot of benefit.

You probably haven't helped the person in the next seat a whole lot, because it is likely to drift across without the obstruction of that first person.

BLOOMBERG