I am an anxious mom.  My 4 year old has a habit of picking his lips if there is any dead skin on it. We went on a subway train while traveling in China, which was quite crowded. He was holding the hand rails and then I found him picking his lips and a piece of skin (5mm*5mm) came off and it bleeded. Is there any chance of him contracting any hepatitis B/C in this case? Since I worry that there might be some hepatitis virus / dried blood from a cut on the handrails of the train. 

Generall, Should I worry that his picking his lips using dirty fingers might somehow give him any blood borne diseases? 

Lastly, last time his pediatrician checked his hepatitis B immunity, it says 'Hep B Surface Ab ' Positive 44.2 mIU/mL'  Is this level high enough? Google says level above 100 is ideal. 

Also, his Hep B 

This is a forum on STD prevention. Although hepatitis B often is sexually transmitted, and hepatitis C rarely is, your question is about non-sexual risks. My reply is therefore brief.

Neither hepatitis C nor B is ever transmitted by contact withi a contaminated environment. Your son's habit is zero risk for either one. Further, his HBsAb test shows his childhood immunization was effective; he is protected against hep B for his entire life. His antibody is definitely high enough:  if any antibody is present at all, at even much lower levels, protection is complete.

So no risk and no worries.

Best wishes-- HHH, MD

Thanks for your instant reply! This is very informative. So does that mean although his dirty fingers making a bleeding wound on his lips by picking, there is no risk even if the surface is contaminated? 

Best,

Cass 

Really, you should not be worried at all about this. Your son's behavior is normal for his age; millions of young children do this sort of thing and do not catch hepatitis, and rarely any other diseases either. In fact, regular contamination from a dirty environment is currently believed to be healthy for children, because it builds a strong immune system that protects people from many serious health problems. Too much cleanliness is actually unhealthy!