Have just bought annual travel insurance with Direct Line who actually have a section called 'Disaster Cover' which includes cover for 'medical epidemic or pandemic'. This will cover you for "travel and accommodation expenses to allow you to continue with your trip or return to the UK if you cannot continue with your trip". (up to £1k, excess = £35.) Obviously it does not cover you if you just change your mind about going due to pandemic, or the Foreign Office advise against travel.
This was the best I could find without spending hours on end squinting at small print on policies!
Most other policies I looked at either did not mention pandemic at all, or specifically excluded cover - these were mostly the cheaper end of the market though.
Maureen