Pokérus made its first appearance in the mainline Pokémon franchise in generation two. And although it’s a virus—something that most would prefer to avoid—Pokémon fans often hunt down infected Pokémon to maximize their team’s potential.
The Pokémon Virus returns in Pokémon Sword and Shield and continues to serve as a way to increase Pokémon stats. If a Pokémon has the disease, it will gain double effort values from battling. Once the Pokémon is healed, it will continue to gain double effort values but will no longer be able to spread the disease to other Pokémon in the party. Similarly, once a Pokémon is cured, it cannot be re-infected with the virus.
Infected Pokémon will have a purple icon next to their name—either a purple smiley icon or a bar that says “Pokérus.” A smiley icon indicates that the Pokémon has recovered from the virus while the bar icon means that the Pokémon is still infected and can spread the infection to others in the team.
Pokémon can spread Pokérus to their squadmates by simply being positioned next to them in the team. Players hoping to spread the virus to their other Pokémon will need to walk around and battle with the Pokémon placed next to each other in the party menu.
How to get Pokévirus
But before players can spread the virus across their team, their Pokémon will have to be infected first. There’s a low chance a Pokémon may be infected with the virus after battling a wild Pokémon—roughly a 1 in 22,000 chance, or about three times rarer than finding a shiny Pokémon in the wild. Players can also receive an infected Pokémon from Link Trade or Surprise Trade, if they’re lucky enough.
Upon talking to a nurse at the Pokémon Center, players will be met with a string of dialogue informing them that one of their Pokémon has Pokérus and a tidbit about the virus. After the nurse’s initial comments, players will no longer receive the dialogue the next time they want to heal their party.
Pokémon will eventually be cured of the virus while in the player’s party within one to four days’ time. But if the Pokémon is placed in the PC, it will not be cured of the disease and will remain infected until it rejoins the party.