Global T-Virus pandemic

The Global t-Virus Outbreak is an event that occurs in the live action film continuity, following the outbreaks of the t-Virus in The Hive and Raccoon City. The entire planet was consumed in a pandemic, wiping out most of humanity.

The Hive
The spread of the virus began in The Hive, a top secret research facility of the Umbrella Corporation dedicated to the research and development of the t-Virus as a biological weapon. However, the facility had been infiltrated by an anti-Umbrella agent named Lisa Addison, whose purpose was to obtain a sample of the virus as evidence. Her activities were discovered by the Hive's chief of security, Alice, and the two began conspiring together to bring down the corporation.

Unbeknownst to either of them, Alice's partner, Spence Parks, was also planning to steal the t-Virus for sale on the black market. Upon obtaining samples of both the t-Virus and anti-virus, he deliberately released it within the Hive to cover his tracks. The facility was sealed by the AI known as the Red Queen, and it's five hundred employees were systematically killed to prevent the outbreak from reaching the surface. A commando team was sent in to investigate, and after a protracted struggle, which resulted in the infection and deaths of all the UBCS unit, the only survivors were Alice and Lisa's brother, Matt Addison. However, when they reached the surface, they were taken prisoner by Umbrella and experimented on in a nearby Raccoon City facility.

The Fall of Raccoon City
In the aftermath of Alice and Matt's capture, the Hive was ordered to be reopened by Dr. Issacs and Major Timothy Cain to ascertain what went on below. Within thirteen hours, zombies and lickers were set loose and spread the virus across the city. Prior to these events, a wall was constructed in eventuality that such a crisis would occur. The city's security measures were swiftly put into place to keep the inhabitants from escaping. During the evacuation of the city, the infection reached the gates and the gates were ordered to be closed immediately. What few survivors remained were trapped in a necropolis dominated by the undead.

Eventually, a decision was reached by Umbrella to sterilize the city. A Precision Tactical Nuclear Device (P.T.N.D.) was launched at sunrise, but not before five survivors, Alice, Jill Valentine, Carlos Oliveira, Lloyd Jefferson Wayne, and the young Angela Ashford, escaped via helicopter with evidence of Umbrella's crimes.

Worldwide Outbreak
Despite the survivors best efforts to expose the truth, Umbrella managed to cover up the incident by stating the destruction of the city was the result of a nuclear meltdown at a power station. But they had made a fatal oversight. A single scientist, Dr. Jim Knable, had been unknowingly infected, and transported to San Francisco. He soon succumbed to the virus' effects and began infecting others. Attempts were made to confine the outbreak to the Mission District, but it was already too late. Unsuspecting carriers had already boarded airplanes, and by the time the President of the United States was briefed on the nature of t-Virus, there were already carriers inside the White House itself.

At the suggestion of his science division head, Dr. Sam Isaacs and Umbrella Chairman Albert Wesker began moving corporation assets to the various underground facilities maintained throughout the world. The corporation would soon become the only remaining entity with the ability to effectively defend itself against victims of it's virus.

It wasn't long before the rest of planet suffered the same fate as the United States. Every attempt at confining or suppressing the infection failed, mankind entered a dark age as the world was overrun by the undead. What few survivors that were left learned to stay on move and avoid large cities where the infection was at it's worse. Speed and constant mobility were their only defence against the the horde of undead. A convoy lead by Claire Redfield and Carlos Oliveira was one such example.

Occasionally, the humans would be aided by nature. Swarms of [infected] crows were known to feed on flesh, infected or otherwise. The entire undead population of Las Vegas was purged in this manner. On the other end of the spectrum, there were survivors who remained in their cities, defending themselves vigorously. A journal discovered by a wandering Alice claims that a community in Alaska, dubbed "Arcadia", remained safe by virtue of it's isolation. A convention center in Baltimore, turned into a safe haven by Jill Valentine, is another example of a city haven for humans. It became a home to more than a hundred humans who managed to make a living among the ruins.The White House itself was also surrounded by walls (which prevents millions of zombies from pouring in) during the outbreak and now houses some remnants of the US Military (or possibly the members of the resistance that is leaded by Leon S.Kennedy.



Survivors
The spread of the t-Virus was devastating, but not absolute. According to the White Queen's satellites scans, out of the planet's pre-outbreak population of 6.5 billion (US numbering system) human inhabitants, there were 1,733,548 people uninfected on the surface. In Resident Evil: Afterlife, survivors are discovered taking refuge in the Los Angeles County Jail and over 2,000 known survivors, including Alice, Claire Redfield, Chris Redfield and K-Mart are aboard the Arcadia, captured by Albert Wesker in a effort to keep his infection in check by feeding on their flesh.

The Cure
Through his experiments, Sam Isaacs came to the realization that "Project Alice", who managed to evade the corporation for five years via staying off the grid and away from other survivors, was the key to their and humanity's survival. Her blood, being the only successful adaption with the t-Virus, could lead to a possible cure, granting total immunity to the pathogen's devastating effects. Upon learning this from the White Queen (the sister computer of the Red Queen), Alice herself was eager to help in the creation of a cure. Although it is still unknown if she succeeded in creating a viable anti-virus, Alice remained steadfast in her vow to make Umbrella pay for their actions.

Trivia

 * Given that the films follow a different continuity than games and the Biohazard Movie Series, this event is considered non-canon.
 * In Resident Evil: Afterlife, the global outbreak is shown to have begun in Tokyo rather than San Francisco. Its "patient zero" was a civilian girl (played by pop singer, Mika Nakashima ) who attacks a businessman in a crowd.
 * According to Paul W.S. Anderson, the outbreak in Japan takes place at the same time as the outbreak in Raccoon City in Resident Evil: Apocalypse.