Thanks for asking. You’re right, a syphilis infection generally takes 7-10 days to clear after treatment is finished. This is why it’s also recommended to use condoms or abstain from certain kinds of sex for that period following treatment to prevent transmision.
And yes, while it should be cleared in 7-10 days, Manitoba recommends that people have follow up re-testing after 3 months. Some people are also tested at 6 months, or at 12 months. The timeline may depend on: the treatment given, how old this infection is, pregnancy, other current sexually transmitted infections, or other factors.
With this follow up testing, your health care provider will monitor not the syphilis bacteria, but the antibodies left in your body after fighting that infection. 7-10 days would not be long enough to get a good picture of what those antibodies are doing, that’s why the follow up is months later. This follow up is key for the healthcare provider to get a picture of how your body is responding, if the stage of syphilis they suspected was correct and to perhaps even detect a re-infection.
(But of course, you are encouraged to test sooner than 3 months if you think you have syphilis again.)
This question is a very thoughful one, and I would encourage you to bring any other questions that you have to your health care provider. They are often able to answer with more detail and any specific information that relates to your individual circumstances.
I hope that’s helpful!