First introduced in the Series V episode "Quarantine" and revisited in the "Back in the Red" trilogy of Series VIII and the novel Last Human, these were discovered and isolated by Dr. Hildegard Lanstrom who postulated that there were negative viruses (which deteriorated the infected) and positive viruses (which made the infected feel better), the following are known:
- Reverse Flu
- Sexual Magnetism
- Luck (Latin name being Felicitus Populi)
Reverse Flu is a basic level positive virus, which gives the infected a feeling of wellbeing and happiness even when the infected has had a tough time, where she believed that 20th century DJ's were constant "sufferers".
The Luck virus was a virus that many contract for short periods at some point in their lives, which allows the infected to do things which are considered almost impossible fairly easy. Allowing Lister to pick four of a kind from a pack of unmarked cards, punch in a door lock code where the chances of punching in the correct combination were "billions to one" (also the code to unlock his wrist restraint and his cell) just by using whatever combination he felt like and stumbling on the components to cure Rimmer of the Holo Virus.
The Sexual Magnetism virus makes the infected irresistible to the opposite sex or seemingly, given sexual orientation, the same sex, where they have an uncontrollable desire to make love to the infected, even if it is Arnold Rimmer (the last one any would want to be seduced by), the only known anti-virus is the Luck Virus, which was discovered by accident by Dave Lister when Kristine Kochanski was overcome by the effects of the Sexual Magnetism virus. When Lister poured the entire tube of the virus on Rimmer when they were in The Tank, nearby convicts looked at Rimmer in a disturbing way...