COVID-19 Health Tips

Note: These tips are based on recent scientific studies that may not yet be peer-reviewed and are subject to corrections. For advice based on established science, please talk to your favorite public health official.

Suggestions for the public

  1. How you can make your air travel safer
    1. Board last. We recognize, of course, that everyone cannot be the last to board. But if you are one of a few people on your flight to read this tip, then you would benefit from reduced exposure time in the aircraft during the boarding process. You may have a slight exposure while walking past seated passengers. However, our simulations indicate that most of the exposure during the boarding process occurs amongst seated passengers and amongst passengers in the aisle (the latter typically when they are stalled waiting for someone to stow their luggage).
    2. Choose your class suitably. Some airlines are keeping the middle seat empty in economy class. In this case, being seated in economy class leads to greater social distancing than if you are in business class, especially if you are in the window seat and you wear a mask. However, if the airline does not keep the middle seats empty, then the business class may be safer. Not flying on that airline is even safer.
    3. Focus on exposure outside the airplane too. The air from the airplane vent is typically pure. Health risk arises from the air that has not gone through the filtration system yet (for example, when the passenger next to you coughs). However, the air in the airport may not be as clean. So, please also read our general suggestions for crowded locations.
  2. How you can be safer in crowds (if you can’t avoid them)
    1. Don’t let the 6-feet threshold give you a false sense of security. Our analysis shows that this is not a fool-proof criterion. People have contacted COVID-19 well beyond the 6-feet limit. The type of activity of an infective person, ventilation system, exposure time, and the number of viruses shed by an infective person, all impact the safe threshold. For example, talking appears to increase the areas of risk compared to keeping quiet, and singing and aerobic exercises substantially increase this area. You may need to keep over a 25 feet threshold at such activities. Gentle exercises, like yoga classes, and moderate activities outdoors, appear not to carry as much risk. If you cannot maintain the required social distance, then please read the suggestion below on mask use.
    2. Wear a good mask and wear it right. There is some disagreement between public health research and engineering research on the effectiveness of masks. Note that when public health research suggests that masks are not very useful, this usually means that their data was too noisy for them to come to conclusions. On the contrary, engineering research typically clearly shows the effectiveness of masks, especially the N95, in filtering out particles of the size that carry viruses. Public health researchers are also concerned about people not wearing an N95 respirator correctly or getting a false sense of security. But this is in your hands; you can wear it correctly and also practice social distancing. Other types of masks are easier to fit correctly, but may not offer as much protection.

Suggestions for decision-makers

  1. Suggestions for airlines
    1. Don’t use back-to-front boarding. Our simulations show a substantial increase in exposure to social contacts from this process. A random boarding process reduces exposure by a factor of two.
    2. Keep the middle seats empty if it is economically viable. Our simulations show that this policy reduces the exposure per person by more than a factor of two.
  2. Suggestions for operations personnel of crowded locations
    1. Use solid partitions in winding queues, enforce a single file queue, and select a suitable queue configuration. Our simulations show that these changes can lead to around a 75% reduction in exposure to social contacts.


  1. T. Islam, M. Sadeghi Lahijani, A. Srinivasan, S. Namilae, A. Mubayi, and M. Scotch. From Bad to Worse: Airline Boarding Changes in Response to COVID-19. Preprint: arxiv 2006.06403, 2020.
  2. Derjany P, Namilae S, Liu D, Srinivasan A (2020) Multiscale Model for the Optimal Design of Pedestrian Queues to Mitigate Infectious Disease Spread. PLoS ONE 15(7): e0235891.
  3. van der Sande M, Teunis P, Sabel R. Professional and home-made face masks reduce exposure to respiratory infections among the general population. PLoS One. 2008;3(7):e2618. Published 2008 Jul 9. doi:10.1371/journal.pone.0002618
  4. Vicki Stover Hertzberg, Howard Weiss, Lisa Elon, Wenpei Si, Sharon L. Norris, The FlyHealthy Research Team. Behaviors, movements, and transmission of droplet-mediated respiratory diseases during transcontinental airline flights. Proceedings of the National Academy of Sciences Apr 2018, 115 (14) 3623-3627; DOI: 10.1073/pnas.1711611115.
  5. Gupta, J.K., Lin, C.‐H. and Chen, Q. (2012). Risk assessment of airborne infectious diseases in aircraft cabins. Indoor Air, 22: 388-395. doi:10.1111/j.1600-0668.2012.00773.x