I believe the relatively new "super gonorrhoea" is the reason some providers have recently stopped offering OWO. Potentially untreatable and undetectable in 10% of infected folks.
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But for me, OWO is my preference, though the risk is concerning.
I haven't seen any reports yet of an untreatable strain. Those reports IIRC were based around a strain resistant to azithromycin on its own, whereas the standard treatment in the UK is I believe a combination of azithromycin and ceftriaxone, both administered at the same time.
Which is not to say there isn't a threat, though it's been discussed many times on UKP, and is part of the wider issue of it being unprofitable for big pharma to develop new antibiotics, so they haven't bothered for some time. There has been talk recently of offering a $1 billion bounty for new antibiotics. Maybe the political classes will sort out effective funding eventually, before any new pandemic. If not it would no doubt happen afterwards (it would probably be profitable for big pharmas to do so on their own as well), but that would be messy and unpleasant.
Pragmatically I think if a nasty strain does emerge I'm unlikely to be amongst the first to catch it and some poor individuals who do will be the canaries for the rest of us, giving us a chance to modify our behaviour.