What science now knows about the risk of COVID-19 transmission on planes

Scientists have found a sharp increase in potential spread during in-flight meal service when everyone has a mask off. He has also learned more about the importance of precautions while boarding and deplaning.

The chances of spreading the virus in planes are very less. But papers published in medical journals suggest they may not be as low as previously suggested in the pandemic.

“At this point, if you take the proper precautions, it’s safe to travel. I think it might be safe,” says Mark Gendreau, MD, chief medical officer at Beverly Hospital near Boston and a specialist in aviation medicine.

As international travel begins to open up more, the US in November eased restrictions for vaccinated travelers from 33 countries, and more travelers will dig into in-flight meals. A recent medical study by a group from the University of Greenwich in London found a 59% higher risk of viral transmission during a one-hour meal service on a 12-hour trip compared to being completely masked for the entire flight Is.

The study, published this spring in the Journal of Travel Medicine, modeled aerosol dispersion in an aircraft cabin. It found that if all passengers wore masks during a 12-hour flight, the chance of average infection could be reduced by 73% with high-efficiency masks and 32% for low-efficiency masks.

The problem comes when everyone takes off their masks at the same time. The researchers suggested a remedy for the food issue: interruption of food delivery so only half the passengers eat at a time and adjacent passengers remain masked.

It will probably be higher than most hungry passengers, and airlines say they are sticking with standard meal-service patterns. Passengers can help protect themselves by avoiding eating while seatmates eat, unless it is someone they know.

Recently published research has also shown that boarding and deplaning carry a higher transmission risk than with boarding a plane.

That’s because people tend to cluster on top of each other and breathe, pulling and pushing bags specifically into the overhead compartment. When seated, the aircraft’s ventilation systems, originally designed to quickly remove cigarette smoke from cabins, allow air to be taken straight down, filtered with hospital-grade equipment, and reduced by 50% before returning to the cabin. Very effective in mixing with outside air.

“We have studied the passenger cabin and ventilation system quite rigorously,” Dr. Gendreau, who is often asked to review travel studies. He cautions that the research published this year was also done with older variants of Kovid-19. Not the circulating, more infectious delta variant.

Recent studies have found that masking reduces the risk of infection and that using an air gasper – an overhead air nozzle that can be adjusted on many airplanes – works to quickly disperse viral particles. Even if it gives you chills, it’s worth opening it up completely and aiming it at the front of your face.

And while the evidence is conflicting, it appears from medical research that business class and first class are areas with less transmission risk as travelers sit farther away.

There is a lot of focus on spreading COVID-19 through travel. Public health experts say airplanes carrying infected passengers have spread the pandemic virus around the world. In addition, passengers worry that one passenger may infect multiple people due to cabin closures.

But the risks for onboard spreads appear to be very low. A recent review of medical research published by the Journal of Travel Medicine on September 3 found 18 studies around the world on in-flight COVID-19 transmission documented 273 “index cases” – passengers who contracted the virus onboard. – and 64 “secondary cases” – 59 passengers and five crew members were found infected during the flight. Two other studies examining wastewater on airplane flights found evidence that infected passengers were likely onboard.

The review included one major caveat: The quality of the evidence was lower than most published studies due to weak contact tracing.

With the new information travel-health experts are raising new questions about airline procedures.

“We know more, but it has prompted more dilemmas and more challenges,” says Dr. Ayesha Khatib, a travel-medicine specialist at the University of Toronto, one of the authors on a review of scientific studies of transmission risks on airplanes. Huh.

The International Air Transport Association, which represents airlines, says airlines have not received clear guidance from authorities on how to better handle meal service.

IATA’s medical advisor, Dr. David Powell, said in a written response to questions, “On long flights, it is not possible to abstain from food and drink. It needs to be remembered that the in-flight phase is unlikely. The highest risks of travel One of the steps.

An American Airlines spokesperson says that on long domestic and international flights, meals are served in coach and premium cabins instead of multiple courses to reduce touchpoints between customers and crew and speed up unmasked meal times . American has also banned the serving of alcohol until January 18.

To ease overcrowding concerns, some airlines in Europe are asking customers to sit until their row is asked to disembark. Some US airlines tried that in the early days of the pandemic. Now the crew moves out of the way of the thundering swarm.

United Airlines says it has asked pilots to keep the airplane’s ventilation system on during boarding and deplaning to maximize airflow. Not every airline does this.

Michael Schultz, an engineer at the University of Dresden’s Institute of Logistics and Aviation in Germany, has studied boarding and deplaning extensively. He says standard boarding makes a substantial number of possible transmissions if an infectious traveler is present.

Random boarding sequences, where passengers are not congregating in the same lines at the same time, would be better at reducing potential transmission, he says. More importantly, hand luggage should be restricted so that a passenger does not have trouble pushing something into the overhead bin while breathing over a seated passenger. Reducing carry-ons can reduce transmission risk by about 75%.

Some precautions airlines will never fly with, such as boarding more passengers by walking outside the tarmac instead of on poorly ventilated jet bridges.

“I’m disappointed that airlines don’t go for the scientific approach,” says Dr. Schultz.

A paper currently undergoing peer review is recent enough to take into account the more infectious Delta variant—and suggest a greater risk to passengers. Researchers in Hong Kong traced a cluster of 50 COVID-19 cases to a New Delhi to Hong Kong flight with 146 passengers in April 2021. Only 20% were symptomatic; Eight of the positive cases were found in children under the age of 2, who were exempted from masking requirements.

On arrival, five passengers tested positive. Since India was considered high-risk, Hong Kong required a 21-day hotel quarantine for all travelers. More test positive during quarantine.