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Fallout 4Diseases
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Diseases and viruses are various conditions, although not mutations, throughout the Fallout series.


Diseases and viruses have played a pivotal role in shaping the world as it was before and after the Great War. Pre-War, various diseases and viruses were often weaponized for use in biological warfare. Old diseases would be modified into entirely new strains deadlier than before,[1] and new diseases would be created in labs to gain the edge in countering offenses on frontlines.[2] Both the United States and China would propagate the use of these weapons of mass destruction during the Resource Wars, amassing massive arsenals of hundreds of pathogens and toxins,[3] until ultimately escalating and taking the final step into nuclear warfare in 2077.[4][5]

New PlagueEdit

Main article: New Plague

Gametitle-VB One such new disease created by the United States would be limit 115 or as it would be commonly known as - New Plague virus. Created in the secret laboratories of Hoover Dam, New Plague would eventually enter the populace after Chinese spies stole samples. It was quickly released in an attempt to apprehend them but only ended up exposing the virus to a crowded area in Denver. which rapidly spread throughout the United States in the 2050s, eventually demanding a national quarantine in 2053.[6] The epidemic became the driving force behind the Pan-Immunity Virion project that paved the way for the Forced Evolutionary Virus.

After the Great War, New Plague would be on the present factors (along with radiation, inbreeding, and FEV) in the mutations present in the Swampfolk, leading their severely deformed appearance as well as their aggressive nature to outsiders. The New Plague virus is likely still a dormant disease in many parts waiting to propagate throughout the population again or having evolved into an entirely new form as Robert MacCready's son Duncan shows symptoms similar to a New Plague infection.[7]

Forced Evolutionary VirusEdit

From the biological arms race, the Forced Evolutionary Virus was created after being spun off from the Pan-Immunity Virion Project with the original intention to create a cure for New Plague, another biological weapon.[4][5] The Forced Evolutionary Virus was a powerful mutagen capable of mutating any organism is came in contact with. FEV would forever change the environment of Earth as it would be released from many of the labs that contained in the Great War and would most notably be used by The Master to en masse create super mutants in New California from 2103 to 2162, finally being discovered and stopped by the Vault Dweller.[8]

The Enclave would utilize FEV multiple times throughout post-war history in an attempt to genocide all mutated human life on Earth or to either gain control of the remaining nuclear arsenal of the United States. Each attempt left the Enclave defeated or in ruin, either collapsing under their own machinations[9] or being routed by the Chosen One and the Lone Wanderer.[10] From their research and projects with FEV, the Enclave would create a second generation of super mutants and propagating Scorchbeasts and the Scorched Plague.

In the Commonwealth, The Institute would use FEV in producing another strain of super mutants. The experiments they conducted further advanced their research in realizing generation 3 synths after finding a pure specimen to draw genetic information from.[11]

Known diseases and virusesEdit

See alsoEdit


  1. Super Ebola virus
  2. New Plague
  3. Sierra Army Depot cryogenically stores Anthrax, Black Plague, Small Pox, Ebola, and Hantavirus
  4. 4.0 4.1 FEV research
  5. 5.0 5.1 Fallout Bible 0:
    "2053 The socially transmitted "New Plague" arises, killing tens of thousands. The United States closes its borders and the first-ever national quarantine is declared. The source of the plague is unknown, but rumors persist that it is a genetically engineered weapon."
    "2062 Despite quarantine measures, the New Plague continues to spread, fueling national paranoia."
    "2073 Sept 15 As China becomes increasingly aggressive with their use of biological weapons, the United States government felt that a countermeasure was needed. The Pan-Immunity Virion Project (PVP) is officially formed and plans are made to begin experiments at the West Tek research facility in Southern California."
    "2077 February FEV Research is leaked to the world through an unknown source. Protests in many major cities and governments around the world, as well as accusations that the US was responsible for the New Plague. FEV is seen as the threat it is, and serves only to fuel tensions."
  6. Gametitle-VB The Prisoner: "{200}{}{PC: What is the New Plague?}"
    ZAX: "{201}{}{"Discovered in 2053, the New Plague was a socially transmitted plague that killed an approximately twenty thousand human beings in the United States, including cities such as Denver, Colorado, Boulder, Colorado, and Colorado Springs. The time of death from identification of symptoms was three to five days. Symptoms included many symptoms in common with the flu or chest cold, and eventually resulted in clogged respiration, killing the infected subject."}
    {202}{}{"The discovery of the New Plague resulted in the 2053 quarantine, and several emergency programs were established to find a cure for the plague. The Boulder Dome has limited information on the New Plague, since it was not one of the research concerns in the Boulder Dome. If you could find a medical research database concerned with the New Plague, or provide me with holodisks related to the New Plague, I could provide you with more information."}
    {203}{}{ "The only way we could fight off the New Plague was by creating better humans."}"
    (ZAX in Boulder dialogue pieces) Gametitle-VB
  7. The Sole Survivor: "You must have had a good reason to leave them behind."
    Robert MacCready: "That's what I keep telling myself. My son... he's sick. I don't know what's wrong with him. One day, he's playing out in the fields behind our farm... the next he took a fever and these blue boils popped up all over his body. Last I saw he was almost to weak to walk. I didn't dare ask him to come with me. Honestly, I don't know how much longer he's going to last."
    (MacCready's dialogue)
  8. Fallout Bible 0: "2162 March 3 Vault Dweller kicks the Master's ass."
  9. Whitespring surveillance recordings
  10. Fallout 2 and Fallout 3 endings
  11. The Sole Survivor: "Human synths? Really?"
    Shaun: "Human-like synths. A great distinction. The Institute endeavored to create synthetic organics. The most logical starting point, of course, was human DNA. Plenty of that was available, of course, but it had all become corrupted. In this... wasteland... radiation affected everyone. Even in their attempts to shield themselves from the world above, members of the Institute had been exposed. Another source was necessary. But then the Institute found me, after discovering records from Vault 111. An infant, frozen in time, protected from the radiation-induced mutations that had crept into every other human cell in the Commonwealth. I was exactly what they needed. And so it was my DNA that became the basis of the synthetic organics used to create every human-like synth you see today. I am their Father. Through Science, we are family. The synths, me... and you."
    (Shaun's dialogue)
  12. Settler: "Damn blood-suckers! I hope nobody gets Lyme's disease."
    (Random encounter)[clarification needed]
  13. "This place is giving me irritable bowel syndrome."
    (Generic quest dialogue)
  14. Lock Joint syringe, Lock joint in Fallout 76
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