What is your approach to relapsing babesiosis in immunosuppressed patients?

The first thing to do is to try to confirm that this is a relapse rather than a reinfection. If it is a true relapse, there is no proven established approach, but these are the options.

1. If possible, try to decrease the level of immunosuppression
2. The IDSA guidelines from 2020 recommend 6 weeks of standard therapy (atovaquone/azithromycin).
3. Some clinicians also add in clindamycin to this regimen. This is what I generally do.
4. If the above fails, one might try atovaquone/proguanil (Malarone) plus azithromycin.