You do not even have to close borders long-term to be a success story. Croatia (an EU country) shares both land and maritime borders with Italy, and a lot of Italians have property in Croatia that they go to on the weekend. So far, there have been 103 deaths and 2,246 cases, with a population of 1.4 million.
Croatia has not had a single case of COVID-19 for 3 days in a row [1], and has been allowing citizens of several European countries, including ones like Germany, come there [2], since mid-May.
This stuff is not rocket science, and while Croatia will not completely eradicate COVID-19, which is unfortunate, it still is impressive.
While it's admirable, Croatia has 2 / 3 times less density of population than Italy. Lombardy alone has twice the population of the whole Croatia and 6 times it's density of population. It's hard to make comparisons
The comparison is not between Croatia and Italy, but between Croatia and Sweden. In the case of Sweden, it has approximately 1/3 of the population density of Croatia.
The fact that Sweden does not have a coronavirus hotspot as a neighbour further indicates that the Croatian outcomes have been much better.
Sweden has a low population density yes, but that's irrelevant - most is unpopulated land, which doesn't have an effect. If you count Greenland when measuring the population density of Denmark, it's super low, but that would be ridiculous.
More relevant measures would be things like urbanization, where Sweden is number 23 in the world and Croatia number 104 (by https://en.wikipedia.org/wiki/Urbanization_by_country). Or, perhaps, the population density of the most dense areas (5,200/km2 for Stockholm, 4,055/km2 for Zagreb). These are just examples of possible metrics, of course there are many more which might be more relevant, but population density of the entire country has no relevance at all.
"it has approximately 1/3 of the population density of Croatia"
Not really. Sweden has a low population density (23/km²) because most of the country has no one living there. The Stockholm region, where the spread of the virus has been the highest, has a population density of 5200/km².
Croatia has not had a single case of COVID-19 for 3 days in a row [1], and has been allowing citizens of several European countries, including ones like Germany, come there [2], since mid-May.
This stuff is not rocket science, and while Croatia will not completely eradicate COVID-19, which is unfortunate, it still is impressive.
[1] https://koronavirus.hr/en [2] https://koronavirus.hr/frequently-asked-questions-and-answer...