I know someone who has a shunt and was in a minor car accident. can the shunt be harmed? their head did not have impact with anything.

Should be checked: To make sure everything working as it should be....

Shunt, car accident: A shunt in the head is most likely to drain fluid from the cranial vault into the blood stream or the peritoneal cavity. The person probably knows the signs when the shunt is not working like the signs of increase intracranial pressure like headache, nausea,vomiting, increase blood pressure, person appears to be confused, double vision, seizures and loss of conciousness

Most likely No: If it was a minor accident most likely the shunt is not disturbed, But always exercise precaution, if the patient has headache or altered mental status or behavior, patient need to be examined and have to have some form of scan of the head.