Good Morning. My name is Marco and I'm also a doctor. Today I took my youngest son to cut hair and realized that the hair trimmer (it was not the blade) made a tiny cut on his skin. He came in shortly after a client left. If that client had HIV had HIV, could my child have been infected? I followed the machine and had no visible blood. You could, kindly, give me a good explanation so I can take it easy.
I do understand the fear and concern you have for your son. But rest assured, there are no means by which HIV could be transmitted in the scenario you describe.
HIV is actually a pretty hard virus to pass on. It cannot live long outside the human body. There haven't been any cases of HIV transmission through casual contact with blood or semen that has been left behind on a surface. It must be transmitted from mucous membranes of one person into the mucous membranes of another, hence why sexual activity and IV drug use are the most common routes (http://www.thebody.com/content/78184/how-many-minutes-will-hiv-survive-outside-the-body.html).
We also understand now that one must have a detectable viral load (over 200 copies) in order to transmit HIV. Most people who are now using HIV treatment are able to keep their viral load below 200 copies or "undetectable." Once someone is undetectable for six months or longer, they cannot pass HIV to others (https://www.cdc.gov/hiv/library/dcl/dcl/092717.html).
If HIV were transmittable by casual contact such as getting a haircut, sharing a bathroom, or even kissing and touching, there would be millions more people with HIV today. I'd encourage you to check out our resource library here at TheBody.com (http://www.thebody.com/content/30024/hiv-transmission.html). And when the time is right, please share this information with your family and community so they can also learn ways to be informed about HIV transmission and prevention.