My thoughts about jake being immune or not changed again. I think he's immune and him punching bows very easily is due to his training as a mercenary as well as him having wesker's genes. I want to say that wesker could also do a powerful melee against monsters before using birkin's t-virus strain. In the beginnings scenario, if you got grabbed by a zombie and manage to shake it off, wesker will do a powerful kick that will instantly kill the zombie. I know that you can prevent yourself from being grabbed if you are careful ( Plus it's optional similar to jake being able to suplex ustanak at the end. ) but the re6 devs definitely took chronicles games into account ( And in fact they did, cause some of re6's story is connected to operation javier. ) when creating jake. Also ı have to agree with c-virus not allowing people to become superhuman in the same way t, g, t-veronica and uroboros can cause c is a mix of 2 viruses plus it's somewhat weakened since carla obtained the t-veronica sample from manuela's body which was obtained from steve's body who was injected with a t-veronica sample that contained alexia's blood; unlike the other 4 ( Especially uroboros, despite jill's antibodies; it was still very strong and lethal virus. ) which are purely progenitor based viruses and more lethal viruses than the regular c. ( Plus c-virus monsters / bows are more easier to control as well. )
About the jake vs ustanak hand to hand fight at chp 5; there's also the factor that ustanak is weakened due to taking a lot of damage previously. ( Plus he cant regenerate, he has a lot of health to compensate for that. ) As ı said previously, jake contains wesker's genes which are one of the reasons other than his very long mercenary training why he has powerful cqc against monsters. You're not forced to do the suplex move on ustanak although it makes jake look extremely badass and is an awesome move. I dont think questioning that is really different from leon being able to suplex / bulldog ganados / zombies in re4 / re6 or chris punching bows or a boulder at the end of re5. It's rule of cool and an over the top nature of re franchise, except increased. ( Which is natural imo; the main numbered re games ( recv included , the rerev games excluded ) got more crazy / over the top starting with the next numbered entry until re7. )
Edit: Jake in chapter 2 says " I'm so glad ı was immune to that shit they gave us. " .
Also someone asked a similar question in re wiki; ı might as well copy paste it here:
Question
" So I'm a little confused as to how things played out with him in regards to his immunity to the C-virus. Sure it's a progenitor based virus but Albert Wesker wasn't exactly immune to progenitor based Viruses considering how he was effected by the experimental strain given to him by Birkin and the Uroborus he took at 5's final fight.
Was he perhaps compatible with the C-Virus or is his immune system just super strong due to his genetics and some possible mutations along the way? Were any of his abilities due to the virus he injected at the start or were they all innate? "
Answer
" The trait Albert passed down was immunity to harmful effects of viruses. Hence why he benefited from the experimental virus and the rest of the recipients did not. That genetic trait itself is a mutation. Jake did not receive any abilities from the C-virus. "