ProMED quoted GIDEON in this post:

there were at least 10 human cases in the Volga delta between
1963 & 1968, and that human seropositivity rates of up to 8 percent
were found in European Russia & Western Siberia (see ProMED post West
Nile virus - former Soviet Union: background 20060908.2548)

In another discussion on measles on the ProMED mailing list – this time in Taiwan – a great reference to the information available in GIDEON, which complements the information available from Taiwan’s CDC:

… according to the Global Infectious Disease & Epidemiology Network – GIDEON, the numbers of clinical cases of measles reported annually in Taiwan were: 1386 in 1988; 44 in 1990; 303 in 1992; 71 in 1993; 101 in 1994; 40 in 1995; 49 in 1996; 63 in 1997; 49 in 1998; 23 in 1999; 48 in 2000; 59 in 2003; 36 in 2004; 39 in 2005; 24 in 2006 — available at http://www.gideononline.com) Taiwan has undertaken the goal of measles elimination by 2010. Data available at the website review a vaccination coverage of the cohort born in 2002 of 95 percent with MMR 1st dose. No information was available on 2nd dose coverages.

A note about Russia and measles also references GIDEON.