There is also at least one study showing (at least) flu infection compelling humans to be more sociable and outgoing, but it was (now that I think of it) conducted by comparing self reported social interaction counts before and after a flu vaccine containing (of course) flu virions.

See references in this article, because I have trouble copying them on mobile.

https://www.psychologytoday.com/intl/blog/darwins-subterrane...