Tonga
Well, that's a bummer - of the three sovereign countries having remained free of COVID-19 up to now, one's now had its first case. Tonga, one of the Pacific island nations, diagnosed a seasonal worker returning from New Zealand.
One can hope that this'll remain the only case they have - outside of other returning workers anyway, which'll always be a problem -, or that perhaps this one'll even turn out to be a fluke (the specificity of these tests is not quite 100% after all, and given how many tests are being conducted, you would expect a large number of false positives worldwide each day).
In any case, this leaves Nauru and Tuvalu as the last sovereign states without cases - though there's also a couple of non-sovereign territories, notably the Cook Islands, Niue and Tokelau in the Pacific, as well as Svalbard and Jan Mayen.
One can hope that this'll remain the only case they have - outside of other returning workers anyway, which'll always be a problem -, or that perhaps this one'll even turn out to be a fluke (the specificity of these tests is not quite 100% after all, and given how many tests are being conducted, you would expect a large number of false positives worldwide each day).
In any case, this leaves Nauru and Tuvalu as the last sovereign states without cases - though there's also a couple of non-sovereign territories, notably the Cook Islands, Niue and Tokelau in the Pacific, as well as Svalbard and Jan Mayen.