It does talk about the G virus though, and I only remember that being in RE2, was the G virus in any other RE?
Obviously the G-virus was in RE3 as well, because this game takes place on September 28th and October 1st, 1998. Jill passed out for two days due to being infected by Nemesis.
RE2 takes place in the night from September 29th to September 30th, 1998. Between the events of RE3. Raccoon City was infected by the G-virus, released by William Birkin when he was assassinated.
The G-virus is also mentioned by William Birkin in RE0 which takes place in the night from July 23rd to July 24th, 1998. He tells Albert Wesker that he needs a little bit more time to finish the G-virus, the place of this conversation can be seen in the current Umbrella Chronicles trailer.
But as has been said before, so far nothing indicates that we will see characters from RE2 in Umbrella Chronicles. Storywise it won't have much influence though, because RE3 takes place in the same timeframe as RE2.