Anybody mentioned mountain ranges yet? Those could certainly house survivor communities - the Alps, Himalaya and the Tibetan Plateu, Maybe the Altai, the Taurus Mountains, definitely the Andes.. maybe more I don't know about.
It would be a harsh life for sure, with major survivor communities probably being confined to the cold of the glaciers and the very highest altitudes. But it would be possible - such places have very little in the way of vermin, it's still possible to keep some hardy types of livestock, and such places are very scarcely populated, thus limiting the Rash. That adds possible communities to South America at least, despite its southern altitude.
In the case of Chile, if the government closed frontiers and any ports soon (what is to say, less than 16 hours after the rash arrived at Barajas Airport in Madrid, the faster route I can imagine), the entire country could survive reasonably well, taking some measures:
- Closing frontiers in a really aggressive manner, with millitary forces shooting to everything that moves in each frontier pass (which are, luckily, less than 15 in the entire country)
- Erradicating mammals in all frontier zones, mainly cammelids and rats in the Andes, and sea mammals in the coasts.
- Creating internal layers or enforcing natural buffer zones, like Atacama desert, that couldn't be crossed without local support (for water, gas and so)
- Disgregating population from cities, mainly to avoid breaks of secondary infections that couldn't be controlled with only national medical resources.
- Establishing strict natality policies, which adapt the population growth to resource availability and the need to repopulate cleansed zones when it becomes possible.
- [very hard] developing reliable energy sources outside fossil fuels, that are basically absent in the territory.
Counterintuitively, Patagonia would be some of the harder places to control, because of the lack of natural frontiers with the much more probably infected Argentina. Maybe some independent communities would arise, but central Chile would certainly not know of them until radio communications are recovered.
And that's a big issue: if in year 90 nordic peoples had archived reliable radio communication, why they haven't stabilished links with other survivor settlements via long-wave radio? What is more, supposing that the rash had just one break in northern Africa, countries like Japan or Chile would have clear advantages in massive survival, and so, in keeping Old World technologies. By year 90, it would be reasonable that those settlements (or, best said, countries) would have reach Scandinavia in search of survivors decades ago.
It leads me to think that the rash could be a multifocal infection, happening in more than a break at a time, eliminating the possibility of these kind of super-developed survivor communities. Of course, just could be that the lack of fossil fuels could make feasible a massive survival rate in isolated countries, with hindered development.