I would legalize it and take it one step further. I'd construct a Registry for which all prospective clients must be part of prior to any contractual engagement with a prostitute. Indeed, prostitutes would be as legally required to refuse services to those not on it, much like how people are legally required to not sell alcohol to minors. All financial dealings the client has with prostitutes will be kept on record and regular STD testing would be required to maintain their license to procure. This way, should an infection ever occur, health officials would be able to quickly reach everyone potentially exposed.
Furthermore, should anyone mistreat one of the prostitutes, that prostitute would be freely able to flag their client's record and attach a negative review (i.e. violent, intimidating, etc.) which would warn other prostitutes to maybe refuse this individual's service. Depending on the severity or number of their infractions, not to mention violent or sexual crimes committed, the client's license could be revoked.
The online database would be maintained as an extension of public health services, not only requiring prospective clients to visit a Doctor or something to get on the Registry, but also to ensure the anonymity which health services already provides. You pay to get on the Registry and to remain on it, prostitutes get taxed appropriately, the increased revenue goes into the Health Care Budget. The money saved from enforcing criminalized prostitution goes into the Law Enforcement Budget.
