(I have just moved this from your other thread, in case you wonder where it has gone to..)
Just found more information on this topic, from the Swiss side of moving to EU countries,
http://www.bag.admin.ch/themen/krank...x.html?lang=en
Persons abroad
If residence abroad has been taken up it is not possible to retain the basic health insurance in Switzerland. Essentially, insurance coverage ceases when one leaves Switzerland. Exceptions are made for certain groups (pensioners, unemployed, cross-border commuters, etc.) on the basis of bilateral agreements with the EU and the agreement with EFTA countries.
In addition, for people who were subject to compulsory health insurance, insurers may (but are not obliged to!) offer to continue to provide coverage on a contractual basis. The contract may be concluded with the same or a different insurer. The insurance relationship is then governed by insurance contract law.