Virus is a 1980 Japanese post-apocalyptic film. It stars some names familiar to me: George Kennedy, Robert Vaughn, Chuck Connors, Olivia Hussey, Edward James Olmos, Glenn Ford.
The film can be seen at the Internet Archive in 7 segments linked here. Part 1 of those 7 is here:
That one is quite a bit longer than the video from googlevideo embedded below:
I watched the longer version. Suitably depressing. The music is lame, so I'm sorry to see Janis Ian's name attached to it.
Midnight Eye has a lengthy review, saying this:
There are some nice performances all round, and the internal dramas which erupt between the various cast members make for some compellingly solid, if somewhat artificial drama. It's a highly watchable piece of early 80s excess, silly perhaps, but undeniably fun
Spinning Image says,
I'll say this for this determinedly miserable film, it doesn't do anything by halves