I am no epidemiologist. Readers know that is not exactly a newsflash. But it is an excuse for taking the easy way out on this post. Instead of analyzing, distilling, and summarizing the mountains of details in new studies on the transmission of SARS-CoV-2, I am including links so readers can peruse them and draw their own conclusions.
The way I see it, there is some good news and news that is not so good for airline passengers. The bad news is it seems that transmission through air travel of SARS-CoV-2, the virus that leads to Covid-19 disease, has been confirmed. The good news is that spreading the virus on airplanes may be harder than previously thought, provided that safety measures are followed.
These are informative and interesting studies you can read at your leisure.
This was reported on September 17, 2020. The conclusion that flying is safe is based on the fact that nationwide a little over 1,000 flight attendants have tested positive for COVID-19, according to data provided by the Association of Flight Attendants (the number includes their members, as well as members of other unions and nonunionized workers). That results in an incidence of about .08% based on 122,000 people being employed as flight attendants at the end of 2019. That rate compares favorably to an incidence of about 2% for the U.S. population as a whole. But now the number of flight attendants being exposed is nowhere close to 122,000 because of drastic cutbacks in airline schedules.
This is a recently released early version of a study that will be published in final form in November in the CDC’s journal Emerging Infectious Diseases . The article reviews transmission of SARS-CoV-2 on Vietnam Airlines Flight 54 from London to Hanoi that departed on March 1, 2020 and arrived on March 2. The flight was a 787-9 with 201 passengers on board. One passenger in business class suffered Covid-19 (the disease) symptoms during the flight. That passenger spread his infection to 15 others on the flight. The study found in part:
Of the 15 persons with flight-associated cases, 12 (80%) had traveled in business class with case 1, and 2 travelers (cases 14 and 15) and 1 flight attendant (case 16) had been in economy class (Figure 1). Among persons in business class, the attack rate was 62% (13/21). Among passengers seated within 2 meters from case 1, which we approximated in business class to be <2 seats away, 11 (92%) were SARS-CoV-2–positive compared with 1 (13%) located >2 seats away (risk ratio 7.3, 95% CI 1.2–46.2) (Table 2)
Not good, but passengers were not wearing masks on this flight. The study concludes that wearing masks and other measures airlines have now implemented like enhanced cabin cleaning and blocking seats are very important ways to limit inflight transmission of SARS-CoV-2.
This study appears in the same CDC journal Emerging Infectious Diseases as the prior study. It analyzes a cluster of SARS-CoV-2 infections on a flight from Boston to Hong Kong that departed on March 9 and arrived on March 10. The flight was a 777-300 with 294 passengers.
After arrival one passenger who was traveling in business class with his wife developed symptoms in Hong Kong. Subsequently, his wife and two flight attendants in business class also tested positive.
The study concludes that “their virus genetic sequences are identical, unique, and belong to a clade not previously identified in Hong Kong, which strongly suggests that the virus can be transmitted during air travel.” This flight also occurred before masks were mandated.
On arrival in Hong Kong, thermal screening and health declaration forms did not reveal any reason for concern. The couple was tested only after the husband developed symptoms in Hing Kong. The flight attendants were tested because they served the couple in business class. The study does not state how many of other the crew members and passengers were tested.
On March 3, 2020, I flew in premium economy on a Cathay Pacific 777-300 form Los Angeles to Hong Kong and connected on to Bangkok, Thailand. The return flights were on March 13. As I reported in this post, the experience in Hong Kong was a little scary.
This is the health declaration form I completed in Hing Kong.
The good news is that proper use of face masks significantly reduces risk of SARS-CoV-2 transmission on airplanes. On September 14, 2020, Harvard University’s T.H. Chan School of Public Health published a a great analysis entitled Face Mask Use In Air Travel.
This report concludes:
In summary, face masks offer an important line of protection against the spread of SARS-CoV-2 by reducing potentially infectious exhaled respiratory particles and providing some barrier protection against inhaled particles. Therefore, despite differences in design and material, face masks of any kind without exhalation valves or vents help to prevent the spread of infectious diseases and should be worn by all people in public places as a mechanism to protect public health during the Covid-19 global pandemic.
Everyone should read this four-page document even if they are not planning travel.
It is clear that SARS-CoV-2 can spread on airplanes. Airlines and passengers can lower the risk of spread. Airlines are using enhanced cleaning, distributing sanitary wipes, reducing interactions between crew and passengers, serving less food and beverages, and some are blocking middle seats. Passengers must wear masks and can further reduce their chances of contracting disease by cleaning the areas they touch, refraining from talking, minimizing eating, and social distancing as much as possible i the airport and onboard.
Still, there are no guarantees. Would you feel the risk is worth taking a flight. What precautions would you use to stay as safe as possible?