New Zealand has done a pretty good job over the last two years. Whether the costs outweigh the benefits is a separate question
The article claims that covid is in all Antarctic bases, but I wasn’t aware that Scott base had any. I can’t find any reports of it either.
Edit: Their report from August had it covid free. https://www.antarcticanz.govt.nz/media/news/antarctica-new-z...
The ISS has remained covid free. Kiribati has too. Tonga had one person arrive with covid but it didn’t progress.
Time will tell if the policies in place will deal with Omicron, though.