thats pretty self-explainatory
Generation IX In Pokémon Scarlet and Violet, Pokérus no longer generates naturally, does not spread to adjacent party Pokémon, cannot be seen on a Pokémon's summary, and does not provide double effort values during battle. However, the data itself is retained in the data structure of the Pokémon and will remain stored with the Pokémon if transferred from previous games via HOME into Scarlet or Violet, despite no longer having any indicator in-game nor in-game effects.
Short answer: There IS no Pokérus in Scarlet and Violet
