Domestic Travel Bans Have To Be Really Long To Work, And Can *Increase* Virus Spread

We tend to look at the success story countries and extrapolate from them, why can’t the U.S. be like Australia? And of course there are reasons like Australia not having to worry about the virus coming in from abroad in as uncontrolled a fashion since the country is an island. But do travel restrictions inside a country, like we’ve seen in Australia where citizens couldn’t travel between states for much of the pandemic, usually work so well?

A new paper out of the University of Chicago finds that domestic travel bans may be counterproductive for controlling spread of Covid-19.

They find that domestic travel restrictions trap migrant workers in cities where the virus is spreading wildly, and that total infections can actually increase when these bans are put in place. They draw on evidence from India, China, Indonesia, the Philippines, South Africa, and Kenya.

[T]wo opposing forces constitute the first-order determinants of total infections at any point in time. On one hand, the longer a travel ban lasts, the less time community transmission exists in the rural sink. Ceteris paribus, this will decrease rural infections. On the other hand, the longer the restrictions remain, the longer migrants are contained within a hotspot where infection rates are rapidly increasing. Consequently, the probability that migrants are infected with Covid-19 rises over time until the city achieves herd immunity, in turn increasing the rate at which they seed the rural sink with infections once the ban is lifted. This drives up cumulative cases at any future date.

(HT: Marginal Revolution)

About Gary Leff

Gary Leff is one of the foremost experts in the field of miles, points, and frequent business travel - a topic he has covered since 2002. Co-founder of frequent flyer community, emcee of the Freddie Awards, and named one of the "World's Top Travel Experts" by Conde' Nast Traveler (2010-Present) Gary has been a guest on most major news media, profiled in several top print publications, and published broadly on the topic of consumer loyalty. More About Gary »

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  1. Australia a “success story?” How many people, even those from very hard hit places, would prefer to be locked into Australia (with loved ones living abroad locked out) without civil rights or ability to travel anywhere, and left slaves to government dikdat over their lives? Happy to take my chances elsewhere.

  2. I read the “paper in progress,” which is neither published or peer-reviewed so far. The argument in the paper is extremely tenuous, and your interpretation of their argument is even more so. What is says is that domestic travel restriction may “trap” some migrant workers in viral hotspots, which may result in increased incidence of infection inside the hotspot. But the mode utterly failed to really take into account the effect of the spread of the virus from high-incidence areas to lower-incidence areas. Putting it together with the fact that nobody knows the real incidence of the infection (both symptomatic and asymptomatic), the conclusions you make are, again, extremely tenuous.

  3. Australia and New Zealand, both isolated island nations with low population density, were “successful” simply because they locked the door. Unfortunately, both also seem to have thrown away the “key” to reopening that door-vaccination.

  4. When France announced a lockdown for Paris, many thousands of people made a mad dash out of the city for anywhere outside the lockdown zone. Local or regional lockdowns are a recipe for spreading the virus from a hot spot.

  5. Well, without respect to this particular article, when there is community spread like topsy on account of a given community having an r naught above 1, efforts to close the border to keep infected out are a bit like closing the barn door after the horse is gone.

  6. how dare you publish this right wing mouth breathing trash. anyone with more then 5 braincells knows that the usa should have been in a total china like lock down with no one allowed to leave the house. if and only if the usa did that then we would have been done in a month. i am so sick of your blog spreading these views from the right wing that has lead to many deaths shame on you. you orange man supporting blog im done with you

  7. @Mak

    My Australian friends are all living life more or less as normal (for a while now). They seem happy. Also concerned for me living in a country that had such a disastrous response and selfish population that kept cases and deaths high on top of half-assed and half-adhered to lockdowns.

  8. @ V – it’s funny, because my friends keep telling me the same thing, how “normal” life is in Australia.

    But the truth is, there’s nothing normal about being restricted from leaving your country, or being prevented from returning home if you’re stranded somewhere else.

    In fact, if you work in universities, or hotels, or airlines, or tourism, nothing is normal. Nor is the downtown core of the major cities “normal” by any measure.

    The premise of normality is simply a falsehood, repeated ad nauseum by politicians and a booster media, no better than those that dribbled from the former President’s mouth or Fox News.

    The US response to Covid was indeed disastrous. No argument there. But beware of the Australian who tells you life is “normal”. Normal for who?

  9. Gary, maybe it’s time to stay in your lane and focus solely on loyalty programs and travel products.

    Spouting off unresearched, unreviewed tenuously linked thoughts from a research paper as hard facts outright undermines your credibility as a journalist and expert on your field. You’re not a doctor or virologist, stop pretending to be one.

    On top of that:
    1) Australia and NZs pandemic response has been first class including in its densely populated big cities like Sydney and Melbourne. There’s nowhere in the world that can operate fully packed 80,000 attendee sporting events, that you can attend dinner without the fear of someone breathing on you and catching the virus, that can travel freely around their own country with no restrictions or testing required.
    2) Australians and Kiwi’s aren’t that worried about international travel for leisure purposes as we see the shit show in places like the US, UK, South America and want nothing to do with that. Australians are allowed to leave the country for work, bereavement, caring for family or even if they’re just leaving for more than three months.
    3) The hotel quarantine system is by far, the most effective control at stopping the virus from entering Australia/NZ, if others had adopted this, the pandemic likely would’ve slowed down considerably sooner.
    4) Domestic restrictions weren’t fun but people got over them. They happen to limit the spread, we all know that and accept that as important. The government props up the airlines during these types of restrictions with the minimum viable air network program and it works well. Now, our restrictions can be as short as 14 days from an outbreak to return to normal, and there’s still exemptions for critical reasons such as caring for a loved one, funerals, critical work, etc.
    5) Our tourism operators are getting heaps of business they’d otherwise never had through targeted stimulus to get people to those destinations like half off flights to popular international toursit destinations. People will need a place to stay, want to explore and do things, all of this is to say whilst not all tourism operators are having the best time, many are thriving and looking for creative and innovative ways to make money which is encouraged.

  10. It seems a bit weird to be in favor of the equivalent of plague rats. Remember all the people fleeing NYC a year ago that brought the virus to other communities?

  11. Bogus theory. China has millions of migrants and their lockdowns last March and April did wonders. Have been virus free for 10+ months and the economy is steaming away. They look at America with disdain–they couldn’t even beat a virus.

    And the US has almost no migrant workers.

  12. Did you even read the paper? It studies specific cases where there are tons of migrant workers who are working far away from their homes in population-dense hot spots, who will almost always return home as soon as the travel ban is lifted if they are out of work (meaning, for them, the total amount of travel is not really changed by the travel ban, and the ban simply delays their eventual trip).

    This is not even remotely similar to the cases that you often rail about, which is the discouraging of discretionary, non-essential travel in the United States, which of course has very few migrant workers.

    In fact, the most similar example to this case study in the U.S. is probably the mass exodus from NYC during the first wave of spring 2020. What this paper is arguing amounts to a statement something like: “If we had decided to institute a domestic travel ban in spring 2020 to prevent people from exiting NYC (like China basically quarantined the entire city of Wuhan), it would have only been effective if the travel ban was long enough for the whole outbreak to pass, because otherwise more people would have been infected while stuck in NYC, and then escaped as soon as the travel ban was lifted, thereby infecting others in different regions.”

    I presume there are very few epidemiologists who would disagree with this above thesis. The same epidemiologists almost unanimously agree that more discretionary, non-essential travel leads to a faster spread of new variants because it creates more local clusters that can seed more mini-outbreaks in each region, and that this multiplying effect is still robust even if the variants are “already here” because the variants are not evenly distributed across regions at equal densities and more travel creates more opportunities for cold spots to turn into hot spots.

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