Major Question?

Hello, I was reading some recent news stories about how the virus may protect the body from some diseases..... however in the midst of reading it I noted that can lead to blindness, cancer and deafness. Is that in such cases where it is left untreated and is this rare or common? Has any doctor seen such result and under what conditions? Would taking Valtrex regularly prevent that? Does the virus travel upwards to the brain progressively or something?