I can tell you from my own experience. I don't work in health but in higher education; a large public sector area also captured by GI - probably to the same extent as the NHS.
I complained of sexual harassment when I was stalked, rubbed up against, and harassed by an older male colleague. I documented these occasions, and after a couple of months, when a clear pattern had emerged and I'd convinced myself I wasn't imaginging things, I reported him.
The shit I took. Thankfully my then departmental head was sympathetic and supportive - it only transpired a long time later that they'd known about this man for aeons, his behaviour had been rugswept, and he should never have got near me in the first place.
His union rep tried to excoriate my character. I was a new staff member then - he'd been there decades - and his rep wanted to collect reports from all colleagues on his character and mine. None of them knew me and a lot were keen to exonerate their eccentric, 'fun' colleague.
When I read the witness reports, I was devastated. Two witnesses did support me, the other two not only mentioned not having seen anything amiss (no issue if they hadn't) but they sang his praises from the rooftops with the clear implication that I was lying. Most involved have left now - as to the one colleague who remains, I am only coldly and formally civil.
When I came back from stress-related sick leave (diagnosed cPTSD) I wanted to hide in a corner and not face anyone. I kept my head down for about two years. Meantime, he announces he's leaving (having been told he'd likely be asked to go) and all the emails start to circulate, including from the witnesses who contributed the report, saying what a brilliant colleague he was and how missed he'd be. That broke me.
Final instalment - my employers gagged me from ever speaking of this on pain of disciplinary action. Even the more recent banning of NDAs, had this been in place, would have done nothing to help me in that situation.
I give you the UK public sector.