The Immune

In a setting where humanity is being wiped out by The Plague, there will sometimes be one person who is mysteriously immune to the disease. This could be due to some inborn genetic resistance to the disease, or it could be that they are unknowingly exposing themselves to the cure in the course of their daily life (particularly if the disease has an Improbable Antidote). On occasion, especially in works that are short or Cut Short, there is no explanation.

Discovering this immune character is often the key to finding a cure to the disease, with the main difficulties being getting them safely to the scientists who can develop a cure and figuring out what factor in their environment protected them. Another possibility is that developing the cure might require extreme measures, leading to dramatic ethical dilemmas and making the immune character unwilling to cooperate.

The heroes will want to protect and study this character to find a cure and save mankind. A Corrupt Corporate Executive may want to kidnap them in order to monopolize the cure. If the disease was deliberately engineered by a villain, then they may want to hunt down and kill the Immune to prevent a cure from being developed.

In darker works, this character's immunity might not be able to be turned into a cure for others, in which case they can become The Aloner in an empty world After the End. In really dark works, someone who had been the Immune ceases to be. Perhaps they were protected by environmental factors that were undermined before they were recognized.

If this character isn't affected by The Virus but is still perfectly capable of spreading it to others, they may also play the role of Typhoid Mary or Poisonous Person. If the character was not human to begin with, Hybrid Overkill Avoidance may protect them from becoming a Hybrid Monster.

Anime & Manga

 * In Higurashi no Naku Koro Ni, Rika.
 * and  are immune to the Medusa Virus in King of Thorn because
 * This is part of the premise of the short-lived manga, Double Arts, in which the world has been decimated by a mysterious plague (a plague with no permanent cure). While there is a small percentage of young women who possess a tolerance to the disease, it is only the protagonist, a young man named Kiri Luchile, who is truly immune to its effects
 * Casshern and Friender are the only ones who don't succumb to the Ruin, which causes the normally immortal robots to rust and decay much faster than in Real Life.

Comics

 * The reason everybody was looking for Ray Palmer in Countdown to Final Crisis
 * And it ended up being a Shaggy Dog Story anyways.
 * Also a plot point in Maximum Clonage arc of Spider-Man, where one person survived the test run of the Jackal's virus
 * The Batman: Contagion story had a series of these, each typically revealing that there was one other person just before dying (and rendering the antibodies in their blood immediately useless).
 * Yorick and Ampersand, the only males to survive the Gendercide in Y the Last Man.
 * In All Star Superman, Steve Lombard was immune to being turned into a Bizarro. He smugly asks Supes to scan him with his X Ray Vision and create the antidote, but Superman answers, embarrassed, "I don't think I can recommend your performance enhancers to the rest of the population".

Film

 * Alice in Resident Evil: Extinction. It doesn't have any actual bearing on the plot, mind; it's just exposited by the White Queen at the end.
 * The survivors of the plague in Doomsday, with Cally in particular serving the role of "make a cure from her blood".
 * The protagonist of I Am Legend is immune to the disease.
 * Not a complete immune, but in 28 Weeks Later the boy did not turn into a zombie despite being bitten due to his blood. But he carries the virus in his blood.
 * In Skinwalkers the key to curing lycanthropy are the antigens in a half-werewolf, half-human boy's blood.
 * Joanie in Warning Sign is immune to the bio-engineered Hate Plague because she's the only pregnant woman in the quarantined facility; the special hormones in her blood is what keeps her safe and is the basis of the cure. What Do You Mean Its Not Symbolic?
 * In the So Bad Its Good movie Robot Monster, the only people who are left alive after the alien invasion are the friends and family of a middle aged scientist who'd dosed them all with a cure-all serum. (Initially though, the scientist thinks it's a protective electric barrier he erected that staved off the alien's attack.)
 * In Contagion Mitch Emhoff turns out to be naturally immune.
 * The doctor's wife in Blindness is the only one whose eyesight is remained in the mysterious blinding epidemic.

Literature

 * The Perfect Dark: Initial Vector novel.
 * A big focus of The Andromeda Strain was finding out why two people were immune to the disease when everyone else died
 * What made it interesting was that they were.
 * In The Changeling Plague, IdahoBlue was one of these for a previous disease epidemic (though not the titular one)
 * In Chasm City of Alastair Reynolds' Revelation Space universe, the cure for the Melding Plague, called Dream Fuel, turns out to be blood harvested from an alien with natural immunity
 * Dr. Robert Neville in virtually every adaptation of I Am Legend.
 * The thief in Brian Evenson's short story Fugue State, who breaks into and loots quarantined apartments.
 * José Saramago's Blindness follows the one woman immune to the plague of blindness.
 * In Oryx and Crake, Snowman aka Jimmy believes that he is the only human left in the world after a man-made hemorrhagic virus destroys humanity in a matter of weeks. He inadvertently gained immunity some time before the outbreak of the pandemic via a vaccine created by his friend Crake.
 * Everyone who lives through the first act of The Stand.
 * Every character in George R. Stewart's "Earth Abides" is immune to the plague for one reason or another - which is only reasonable, since all the non-immunes die within the first few pages.
 * In Diario De Un Zombi Paula is immune to the zombie virus, a major plot point since finding out why can save the human race.

Live Action Television

 * There was a Star Trek Voyager episode where B'Elanna's unborn baby provided the cure to a Klingon disease
 * And come to think of it, she was also the source of the cure for the Vidiian Phage
 * Also from Star Trek the Original Series, Pavel Chekov in the episode "The Deadly Years." The landing party members age rapidly, except for him, which provides the key to discovering the Improbable Antidote.
 * Heroes: Mohinder's blood carries the cure for the Shanti virus
 * A big plot point in the second season of Dark Angel and the three follow-up novels. The Breeding Cult plan to unleash a disease that only they will survive, but Max turns out to possess total immunity
 * An episode of The X Files dealt with an oil rig worker who was immune to the alien black oil.
 * An episode of Terminator: The Sarah Connor Chronicles revolved around them having to save a woman who will be naturally immune to a disease Skynet engineers to wipe out the Resistance.
 * In the BBC series Survivors (the 2008 remake/"reimagining"), the last remnants of humanity are those who never caught the "European Flu" or who are naturally immune to it. Abby is the only person to ever develop symptoms but then recover, which causes her to get abducted in the season one finale.
 * The Stargate SG 1 episode "The Broca Divide", where.

Tabletop Games

 * In Magic the Gathering, several members of the Mirran Resistance against New Phyrexia are immune to Phyresis, the most notable one being the Sylvok outcast Melira.
 * An expensive (and frequently banned) merit in Werewolf: The Apocalypse makes the character immune to contamination by Wyrm taint. The book notes that this will probably lead to some dangerous missions.

Video Games

 * As an Anti Frustration Feature, this is usually the case with anything involving zombies or similar creatures in video games. There are games where you have to manage your infection level, but they tend to be rare (examples include Extermination or Resident Evil: Outbreak.)
 * In Infected (2005), the main character is not only immune against the zombies, but his/her blood is only thing (short of a nuke) that can kill the zombies.
 * In Halo, 1stSgt-to-SgtMaj Johnson was immune to infection by The Flood, either due to "Boren's Syndrome" caused by "overexposure to plasma grenade radiation", or.
 * The survivors in Left 4 Dead.
 * Some of the graffiti in the second game and radio chatter near the Bridge Finale suggests
 * Not so much a plague as a curse, but Adell in Disgaea 2 is the only one who doesn't turn demonic under Zenon's influence.
 * The baby in The Pitt DLC of Fallout 3.
 * of Ever 17, whose blood provides the cure for Tief Blau.
 * Samus in Metroid Fusion becomes immune to the X parasite in the opening. She got infected and some scientists try an experimental cure: cells from the (now dead) baby metroid. It works, and she gets sent to exterminate the X in the BSL station.
 * 1213:, which sets up the horrifying ending.
 * Reimi in Star Ocean: The Last Hope. This is because . Unfortunately, she ended up with a case of Survivor Guilt when a radiation leak killed off all of her friends except for her.
 * The four survivors in Dead Island are immune to the virus that turns the entire island of Banoi into zombies.

Webcomics

 * This is the reason Mavon's plague didn't completely sterilize the Earth's human population in The Wandering Ones.
 * Uncreation is about an entire knightly order of them, who stage crusades in the plagued lands on the behalf of The Empire.

Western Animation

 * A The Simpsons Halloween special had Bart immune to the zombifying effects of the Krusty Burger. The survivors of the outbreak wanted to eat Bart, but they compromised by having Bart taking a bath with their food.
 * The lice episode of Invader Zim. Zim (and Ms. Bitters, actually) are immune to the lice infestation. This leads to Zim being studied, and guess what? His skin, it destroys the lice! This lead to the creation of a Skin Gun to take down the "lice Queen". They do eradicate the Queen at least... except.
 * In the television version of the X-Men "Legacy Virus" storyline, Cable came back in time to ensure that Wolverine would be infected with the titular virus, because his healing factor would both render him immune and lead to the development of a cure.

Real Life

 * Dairy farmers in the 18th century were found to be immune to smallpox, due to exposure to cowpox.
 * Mary Mallon, otherwise known as "Typhoid Mary".
 * Individuals with the Delta 32 Mutation are immune or highly resistant to HIV infection. Historical and family records indicate that the ancestors of these individuals also had a higher survival rate during the Black Plague.
 * Indigenous populations in areas where malaria is a concern are often prone to sickle-cell anemia, a genetic disorder characterized by malformed blood cells, which hinders the development of the virus responsible for malaria. However, due to modern medicine, malaria is treatable and a lesser concern.