I've never had sex, and I've never shared a syringe for drug use, but I'm terrified of getting an infection from a reused needle or syringe. When I used to see a doctor in a Chinese hospital, the doctor would ask me to take a blood test, including a booster shot of the Pfizer vaccine, which I got in the US this year. These seem to be some routine and common steps. I ignored whether the medical staff switched to new syringes and needles during these procedures. Although I know it is ridiculous and disrespectful to doubt the professionalism of medical staff in today's medical conditions. But I fear the potential risk, even if it's infinitely close to zero. So I would like to ask if that person is HIV-positive before I draw blood or get the vaccine, will I have a high chance of being infected?