Prior to the Covid-19 pandemic, conventional wisdom in public health was that travel bans didn’t make sense. There’s now a reconsideration of that view, though that doesn’t mean travel bans make sense in all contexts either.
I’ve argued that the U.S. ban on travel from China was poorly executed, the ban on travel from Europe came too late, and the list of countries chosen for bans was incomplete. Once the virus was spreading, the U.S. didn’t ban travel within the country. Travel bans can work – see New Zealand, Australia, Fiji, etc. – but they have to be absolute and they can’t be lifted until the threat has passed.
.@kakape asks the $64 trillion dollar question: How does @WHO feel about travel restrictions now? Question comes in the context of the emergence of new variants in the UK & South Africa.
David Heymann, chair of a WHO advisory group: That's a country decision.
— Helen Branswell (@HelenBranswell) December 28, 2020
The U.S. has proven itself incapable of effectively implementing a travel ban whether it was early in the pandemic when the CDC told local health departments not to bother with contact tracing of international arrivals for a few days while it updated its systems, or banning arrivals from China directly but allowing people to fly to Vancouver and cross into the U.S. by land. The testing requirement on U.K. arrivals works a bit better because the government relies on the airlines to enforce it.
There are basically two reasons to impose a travel ban during a pandemic:
- The virus is not currently spreading in the community, and a travel ban may avoiding importing the virus. That’s why restrictions in low-transmission countries like New Zealand, Australia, Vietnam, Thailand, Cambodia and Laos (among others) can make good sense.
- The hospital system is in danger of becoming overloaded. Even if the virus is already spreading, bringing more into a community could tip over a hospital system to the point that care might have to be rationed.
If a virus is already spreading but not overwhelming hospitals then travel bans don’t really serve a significant public health purpose. Where virus is widespread, adding incremental cases doesn’t change the trajectory of the pandemic.
And most discussion of travel bans assume that announcing a policy and implementing it are the same thing. The U.S. has proven that’s not the case.
It’s hard to know ex ante whether a travel ban is the right policy to follow in a pandemic, even if it can be implemented well, because you don’t know the course of the pandemic. If it’s long-lasting, then the ban must be also – otherwise, when it’s lifted, all of a country’s citizens are freshly vulnerable to the virus.
Travel bans have worked out well for many island nations that could pull it off, both because of the effectiveness of implementation but also because vaccines are coming. Right now it makes good sense to hold the virus at bay as much as possible, because help is just around the corner.
U.S. attempts did not work out well, and of course there were no outright bans on domestic travel – only roadblocks on internal travel implemented in a haphazard way.
Of course if the CDC hadn’t failed at testing for six weeks at the start of the pandemic, and if the FDA hadn’t blocked use of other tests, we might have known where the virus was – and where it wasn’t – and have had some idea at what better policy might have looked like before it was too late.