What’s wrong with “he or she”? Why should we give up the ability to distinguish plural from singular?
For that matter, why can’t the authorities acknowledge whether this individual is male or female? That’s not sensitive information that would help someone identify the person.
It’s been used for a very long time, long before all the ‘pronoun’ stuff. He or she is ‘clunkier’ in speech as well as in writing. (You probably used the singular they yourself in the past. Before the new pronoun business, nobody thought anything of it.
I don’t think it’s the habit of ‘authorities’ to release any information at all about someone’s medical issues.
(Generally in a case like this, people with whom the individual would have come into contact are alerted that they may have been at risk.)