> I'm also not sure countries have the resources to enforce huge amounts of tests at the border.
Right.
One issue with testing is that the only test you can do for masses in a border are basic health checks like temperature, but aside from all general issues with such kind of test (people are exhausted after travelling on a plane, having to do a test, ...) with COVID symptoms often only appear after one had been infectious for a while already, so one can pass by undetected and still spread.
Things like PCR tests take time and effort and have notable cost, which makes it hard to apply on a larger entrance port.
Either shut down completely (maybe based on origin region or recently visited regions) or be prepared to handle afterwards ... tracing contacts to identify potential carriers after ridentifying infected is a way which is at least a bit promising.
> Either shut down completely (maybe based on origin region or recently visited regions) or be prepared to handle afterwards
If you only shut down based on recently visited regions, you're likely to import cases anyways. With CoVID-19, it takes several weeks to identify an outbreak in a region (especially without extensive testing). By the time you shut down travel from a given region, you've probably already been importing cases for weeks.
The WHO has gotten a huge amount of flak for not calling for travel restrictions during this pandemic. But their recommendations were based on the ineffectiveness of travel restrictions,* according to previous research. They recommended screening passengers for symptoms, but also told countries to take measures to limit spread (like testing and contact tracing), on the assumption that countries would import cases.
* The WHO's recommendations were also based on the International Health Regulations, an international treaty that basically every country on Earth has joined. Most of the public is unaware of the IHR or what it says about travel restrictions, or of the history of the WHO (one of its founding goals was to stop countries from automatically shutting their borders whenever there was an outbreak, and instead to take rational, evidence-based measures).
Right.
One issue with testing is that the only test you can do for masses in a border are basic health checks like temperature, but aside from all general issues with such kind of test (people are exhausted after travelling on a plane, having to do a test, ...) with COVID symptoms often only appear after one had been infectious for a while already, so one can pass by undetected and still spread.
Things like PCR tests take time and effort and have notable cost, which makes it hard to apply on a larger entrance port.
Either shut down completely (maybe based on origin region or recently visited regions) or be prepared to handle afterwards ... tracing contacts to identify potential carriers after ridentifying infected is a way which is at least a bit promising.