Consistent Group Membership for Epidemic Control

This paper argues that having a mutually-consistent and reasonably small network of contacts can help in controlling coronavirus spread…for example, if a group of 7 people work together and also socialize together, they are better-off from a potential infection standpoint than if individuals in the group are socializing with different, and frequently changing, sets of people.

Somewhat related:  the Federal Aviation Administration is taking steps to limit the spread of coronavirus in air traffic control facilities:

Each air traffic control facility is establishing separate teams of controllers that will stay together throughout the duty week. Each crew will contain the same employees, limiting the possibility of cross-exposure to COVID-19 that would come through normal shift rotations. If a person on one team gets sick, the only people who would be exposed are the other people on that team.

So, presumably, if one member of a team gets sick, all the team members would go home until they can get tested and found coronavirus free, and a new team will be swapped in to support operational needs. Not sure how large these teams are: in a control tower for a medium-sized airport, a team might consist of all the people working on a particular shift, but for a large facility like Potomac Approach or Kansas City Center, I imagine that the teams must comprise only subsets of the total workforce; probably people who work in close proximity to one another.

4 thoughts on “Consistent Group Membership for Epidemic Control”

  1. This makes good sense. Limiting contacts with strangers who may be vectors is a good strategy. Smallpox, for example, will only survive when there is a population of greater than 250,000 because those who contract it die or become immune. That is why it is believed to have originated in India. It is only transmitted by humans.

    Diseases with animal vectors originated with agriculture and have persisted in areas like rural China where people and animals lived in close proximity. Malaria needs the right mosquito and, I believe, yellow fever came to the western hemisphere with its mosquito, the Aedes aegypti, which was native to Africa and was imported with African slaves. It came to Philadelphia in 1793 and killed 10% of the population. The Zika virus has adopted it as its vector.

    Anopheles mosquitoes are found in all continents except Antartica. They are the vector for Malaria.

    Limiting human contacts to small groups was the rule until modern communications, especially air travel. Given that air travel will resumes, we will see a series of epidemics, which may be the dominant feature of medical care for the next century. With the tendency for RNA viruses to mutate, vaccines may be less useful than drugs like Hydroxychloroquine and the anti-virals.

  2. Mike K….”Limiting human contacts to small groups was the rule until modern communications, especially air travel. Given that air travel will resumes, we will see a series of epidemics, which may be the dominant feature of medical care for the next century.”

    Is it really a matter of air travel specifically, or *any* travel mode which is low-cost and convenient enough to encourage a large number of people to travel? For example, if ocean liners became a thing again…say, 3 days to cross the Atlantic…would that have any benefits over air travel from an epidemic-propagation standpoint? I guess the longer travel time would have *some* benefit in improving the chances that the disease develops enough to be detected before reaching the destination…but OTOH, probably more chance of infecting other people on the ship than on a plane, due to longer travel time and a large # of people aboard/

  3. Some trade-offs to consider with the ATC. It’s pretty well established that most everything related to mental function goes to hell when you change shifts. This way, everybody is in the same condition at the same time. If there were more than 3 planes in the air at the same time, there might be problems. I don’t see what would be gained by “quarantining” the whole group. It would be far too late to shield anyone else that shared the facilities.

    I doubt that there is anything better at spreading airborne bugs than an airplane. Hours of close proximity, recirculated, very dry air and cleanliness that is at best a sort of vague notion. A cruise ship would be a close second but more for contact spread than airborne.

  4. Is it really a matter of air travel specifically, or *any* travel mode which is low-cost and convenient enough to encourage a large number of people to travel?

    It is pretty much air travel. Alexander’s soldiers, returning from India, may have brought leprosy as it has a long latent period.

    Plague came to Constantinople with ships and their rats. The rats carried the fleas, which carried the Yersinia organisms.

    Measles and smallpox require large populations of humans that are not immune. Typically, army camps were the vector. Meningococcus are the most recent plague of such settings, including college dorms.

    Ships were slow enough that incubation periods were usually longer than the travel time, hence “Bills of Health.”

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