My understanding is that travel bans were widely believed to have greater costs than benefits before COVID. There are various quotes along those lines described in the (rather cynical) Lessons From the Crisis post on the topic of border closures.
In February 2020, I believed border closures werenāt worth it. I thought they disincentivised countries from being transparent about emerging outbreaks (because said countries would face economic punishment via closed borders) and could only slow down the spread of a disease, not stop it. While Iām still not entirely sure about the relative benefits of open reporting vs. slowed spread, I was definitely underestimating the benefits of the latter. Evidence from Vietnam and New Zealand shows that early and strong international border controls can indeed slow the spread to the point where local outbreaks donāt spiral beyond easy containment.
There was insufficient evidence to draw firm conclusions about the effectiveness of travelārelated quarantine on its own. Some of the included studies suggest that effects are likely to depend on factors such as the stage of the epidemic, the interconnectedness of countries, local measures undertaken to contain community transmission, and the extent of implementation and adherence.
The study finds that the domestic travel measures implemented in Wuhan were effective at reducing the importation of cases internationally and within China and that additional travel restrictions were also likely important. The study also finds that travel measures are more effective when implemented earlier in the outbreak.
My understanding is that travel bans were widely believed to have greater costs than benefits before COVID. There are various quotes along those lines described in the (rather cynical) Lessons From the Crisis post on the topic of border closures.
In February 2020, I believed border closures werenāt worth it. I thought they disincentivised countries from being transparent about emerging outbreaks (because said countries would face economic punishment via closed borders) and could only slow down the spread of a disease, not stop it. While Iām still not entirely sure about the relative benefits of open reporting vs. slowed spread, I was definitely underestimating the benefits of the latter. Evidence from Vietnam and New Zealand shows that early and strong international border controls can indeed slow the spread to the point where local outbreaks donāt spiral beyond easy containment.
To link you to some resources, a September 2020 Cochrane meta-analysis, Travelārelated control measures to contain the COVIDā19 pandemic: a rapid review, concluded that:
The February 2021 paper Evidence of the effectiveness of travel-related measures during the early phase of the COVID-19 pandemic: a rapid systematic review (PDF link) (which I found in the recent Vox article Vietnam defied the experts and sealed its border to keep Covid-19 out. It worked.) concluded that:
Thank you, very helpful!