Game is as good as done right here.
As punishment for lying in practice round, no one cooperate with Yakuya and gang. There is no way for 3 players to generate > 4 vaccines. They have lost before the game started for breach of trust.
The rest just need to cooperate to all gain > 4 vaccines. No one is permitted to make contact until this is sorted out.
Protagonist trio know that since 1 of them is infected, there is only 1 other infected in the other 6. Trio can pretend not to know at first. Get the other infected to reveal themselves (give them adequate time), and pretend to search for the second infected until end of first round, only to reveal afterwards that bandana is infected after they are confident that the person claiming is indeed infected.
Alternatively, if no one but bandana admits, we pick a random ordering and pair the remaining 6 players up. They are to make contact with the other person, check on status, then report on their findings. If someone turns infected, then other person is lying. The remaining group kicks this person out. This is incentive not to lie.
Akiyama and Nao then each make contact with bandana and other infected person. So they are the only ones infected now. All others should be Normal assuming that the infected person and bandana are telling the truth. The six of them and bandana each generate > 4 vaccines, then cure Akiyama and Nao, who proceed to generate > 4 vaccines.
gg
