That being said yes - you can use REASONABLE force to prevent someone from spitting on you.
Are you allowed to hit someone if they spit on you. A crime involves the legal theory of a mens rea which means criminal mind or having such a state of mind while committing an act. No women or men or child or eldery or teacher or anyone one else should be violent to one another. If the spitter was sick or had some kind of virus and tried to spit at you in the eye or any other mucous-related orifice of your body and such was done WITHOUT YOUR CONSENT this can be considered ASSAULT.
In a physical confrontation self defense typically allows a person who reasonably believes he is about to be hit to defend himself. First the sin may be the same but the consequences are not. When you fight back you are participating agreeing to play the game.
It is like the death penalty is hypocritical and is just as bad because they are doing exactly the same thing. This man-like female whom my half-wit brother knows started screaming three inches away from my face at his place. Though the risk of transmitting HIV through biting spitting or sharing of sex toys is negligible at least 11 states have laws on the books criminalizing potential HIV transmission through such acts.
Washington is the only state in the country where fist-fighting by agreement is legal. However if youve already been hit and the person who hit you indicates by words or actions that he is not going to hit you again self defense generally does not allow you to hit that person back. If someone is going to hit you to mug you then you can hit them back.
While the main way the virus is transmitted is person-to-person according to the CDC it still may be possible to get the virus by touching a surface that has the virus on it and then touching. That happened to me once I laugh when I think I had the balls to speak up the way I did to this menace of a woman. Its hard to argue self-defense when youre literally on the attack.
In April a Florida woman who allegedly spit on a police officer was charged with criminal transmission of HIV and jailed according to CBS Miami. There are circumstances where it is legal to hit people for example in the context of a sporting event like boxing football or another contact sport. You dont have to prove anything.