What Science Now Knows About the Risk of Covid-19 Infection on Airplanes

The chances of the virus spreading to an airplane remain very low. However, papers published in medical journals suggest that it may not be as low as suggested in the early days of the pandemic.

“With proper precautions, we can still travel safely at this point,” said Mark Gendrow, chief medical officer and aviation medicine expert at Beverly Hospital near Boston. “I think it’s safer.”

As overseas travel begins to open, the United States Relax restrictions For travelers vaccinated from 33 countries in November, more travelers will delve into in-flight meals.A recent medical study by a group at the University of Greenwich in London found 59% High risk of virus infection During a 1-hour meal service on a 12-hour trip, compared to remaining completely masked throughout the flight.

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

The problem occurs when everyone removes the mask at the same time. Researcher-suggested solution to food problems: Stagger the delivery of meals so that only half of the passengers eat at a time and adjacent passengers remain masked.

That’s probably more than most hungry travelers tolerate, and airlines say they stick to standard dietary service patterns. Passengers can help protect themselves by avoiding meals while their seatmates are eating, unless it is someone they know.

A recently published study also shows that boarding and takeoff of an airplane are at higher risk of infection than when the airplane is in the air.

That’s because people get together to breathe over each other, especially pulling and pushing bags with overhead bottles. The aircraft ventilation system, originally designed to quickly remove tobacco smoke from the cabin when seated, Move the air straight down, Filter with hospital grade equipment, mix with 50% outside air and return to cabin.

“We have studied cabins and ventilation systems fairly rigorously,” says Dr. Gendrow, who is often asked to peer-review travel studies. He warns that even the study published this year was done with an early mutant of circulating Covid-19 rather than the more contagious delta mutant.

According to recent studies, masking reduces the risk of infection, and air gaspers (overhead air nozzles that can be adjusted on many planes) can be used to quickly disperse virus particles. Even when it gets cold, it’s worth opening it fully and pointing it in front of your face.

Evidence is inconsistent, but from medical research, business class and first class appear to be areas of low risk of infection because passengers sit apart.

Spreading Covid-19 on a trip has received a lot of attention. Public health experts say the plane spread the pandemic virus around the world by transporting infected travelers. In addition, due to the small cabin, the leaflets are worried that one passenger will infect many passengers.

However, the risk of onboard spreads seems to be very small.recently Review of medical research Eighteen studies of in-flight Covid-19 infections, published by the Journal of Travel Medicine on September 3, were found. These are 273 “index cases” (passengers who carried the virus on board) and 64 “secondary cases” (59 passengers who were found to be infected on board). Two other studies examined found evidence that infected passengers were likely to be on board.

The review contained one big warning. The quality of evidence from most published studies was low due to weak contact tracing.

With new information, travel health professionals are raising new questions about airline procedures.

“We know more, but it has created more dilemmas and more challenges,” said a travel medicine specialist at the University of Toronto, one of the authors of a review of scientific research on the transmission risk of airplanes. The home, Dr. Aisha Kativ, says.

The International Air Transport Association, which represents the airline, says the airline does not have clear guidance from the authorities on how best to handle meal services.

“On longer flights, eating and drinking is impossible,” said Dr. David Powell, IATA’s medical adviser, in a written answer to the question. “It’s important to remember that the in-flight stage is likely not one of the most risky stages of the journey.”

On long domestic and international flights, meals in coaches and premium cabins have multiple points of contact between customers and crew to reduce unmasked meal times, according to an American Airlines spokeswoman. It is offered as a single service rather than a course. Americans also stopped serving alcohol until January 18.

Disregarding congestion concerns, some European airlines have instructed customers to stay seated until the line is called to disembark. Some US airlines tried it early in the pandemic. Now the crew is out of the way of the thunder swarm.

United Airlines states that it has instructed pilots to keep the aircraft’s ventilation system running during boarding and takeoff to maximize airflow. Not all airlines do so.

Michael Schultz, an engineer at the Logistics and Aviation Institute at the Dresden University of Technology in Germany, has extensively studied boarding and unplanning. He says that if there are infectious passengers, standard boarding creates a significant number of possible transmissions.

Random boarding sequences, where not all passengers are stacked in the same row at the same time, would be good for reducing possible transmission, he says. More importantly, limit your baggage so that you don’t have to struggle to push something into the overhead bin when one passenger is breathing over a seated passenger. Reducing carry-on can reduce the risk of infection by about 75%.

Some precautions, such as walking on an outdoor tarmac to carry more passengers instead of a poorly ventilated boarding bridge, will never be skipped by airlines.

“I’m disappointed that airlines aren’t taking a scientific approach,” says Dr. Schultz.

One paper that is currently peer-reviewed is recent enough to take into account the more contagious Delta variant, suggesting more risk for travelers. Researchers in Hong Kong tracked a cluster of 50 Covid-19 cases from New Delhi to a flight carrying 146 passengers to Hong Kong in April 2021. Only 20% had symptoms. Eight of the positive cases were detected in children under the age of 2 who were exempt from masking requirements.

On arrival, five passengers were positive. All passengers in Hong Kong required 21 days of hotel quarantine because India was considered high risk. Further tests were positive during quarantine.

Write to Scott McCartney [email protected]