Back in 2005 World of Warcraft was ravaged by a digital plague that once removed from the raid dungeon it spawned in infected some four million players, spread across servers as how to give it to others was discovered, and left cities barren, skeleton-littered wastelands for a month before developers Blizzard were able to fix it. Now, somehow, briefly, someone managed to yet again spread the dreaded disease in World of Warcraft Classic. Posted to Reddit a few days ago is a bit of footage of WoW classic characters in Alliance capital Stormwind spreading the plague amongst each other in true 2005 fashion.
It's not clear how the debuff got out of the raid instance this time. Some have suggested it wasn't that precise Corrupted Blood effect from the raid, rather one created by a weaker version of boss Hakkar the Soulflayer in another dungeon. Corrupted Blood is perhaps one of the most famous events in the history of MMOs, breaking containment at that time to even be covered in mainstream press and receive attention from scientific authorities.
In 2007 a study of the corrupted blood incident was published in The Lancet, one of the oldest and most respected peer-reviewed medical journals in the world. To quote that piece: "The Corrupted Blood outbreak in World of Warcraft represents both a missed opportunity and an exciting new direction for future epidemiological research." That turned out to be entirely true.
During the 2020 Covid-19 Pandemic that data was referenced and consider.