Sure you can, theoretically, get other STDs which tend to survive on places such as toilet seats for some time, but, the chances are very unlikely. But HIV, there is no way, the air kills HIV instantaneously and it cannot survive outside living organisms.
Moreover, to calm you down, even if you cut a person with a knife who's HIV positive, and then during couple of seconds you cut yourself with the same knife, it is very unlikely that you will get HIV, in fact, nearly impossible since HIV will be so to say paralyzed instantaneously with the air contact.
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