It's likely that one or more forms of HHV-6 could spread periodically from person to person because when this virus awakens it can begin shedding and can be potentially transmitted via saliva. But we don't have good knowledge of transmission, namely again because federal funding is so ridiculously low for HHV-6 research. There is no standard test for HHV-6, partly due to lack of government funding interest in this entire area. Preliminary data show that there is a good correspondence between symptoms in MS when the virus is active. Similar research is being monitored with chronic fatigue patients.
Early signs are encouraging but a lot more work needs to be done.
Also, there are lab studies that show anti-herpes medications might have a neutralizing effect on the virus. But clinical studies must be done before anyone reaches a conclusion about this. But here again, due to lack of funding in this area, there is not much to go on. It is apparent that herpes viruses can interact with one another, one reactivating another. But don't jump to conclusions here either because there is a lot going on in the body's internal environment that requires careful study before we understand how any combination of viruses may attack key cells.