VDRL test may give false positive results and it happens not so rarely. There are many causes for this, and a vaccine is unlikely one of those.
Anyway, VDRL is an indirect test, while TPHA is a specific treponemal test which is always more specific and more sensitive.
The pimple on your anus is unrelated, while there may be an unnoticed primary chancre in your mouth (assuming you gave oral sex). If you only received oral sex, you don't have to worry about syphilis.
No worries on HIV either.
As AuntieJesse said, positive VDRL plus negative TPHA should be considered a false positive. But there is a tiny possibility that TPHA test was wrong, so the doctor must be careful and must be 100% sure to rule out syphilis.
If you gave unprotected oral sex, I suggest doing another syphilis test, preferably a different combo (RPR + EIA or TPPA), just make sure it includes a specific treponemal test.
I wouldn't worry much since VDRL test is notorious for its false positives.
What is happening with the VDRL titers? Are they going up? Down?
The standard is that if you have a positive VDRL or RPR and a negative TPHA, the VDRL is a false positive.
I don't know that we have enough info on the covid vaccines to know if that contributes, but historically, vaccines haven't caused false positives. Things that can are autoimmune disorders, Lyme Disease, some tropical diseases like malaria, HIV.
Have you ever had syphilis before?
If you don't practice anal sex, the sore on your anus can't be a syphilis sore. Sores appear at the point of infection. Syphilis sores are flat, round and painless.
Do you think I should ask for a neurosyphilis test as well? Also, should I ask her to repeat the penicillin injections after the doxy course is completed? Yes, TB prevalence is high in India. Not sure about LGV. And when should I test for the titers?
Sad to hear you have syphilis; good news it is very curable. I have never heard of a negative TPHA turning positive, so I assume there was some human error involved. It was a good call to do another test. FTA test is not necessary, time to treat syphilis.
It is not possible to say for sure how long you have been infected. VDRL titer is not very high, so it may still be a new infection (end of primary stage, from that exposure 6 weeks ago). It might be an older infection, but I doubt you missed it a rash since 2019. I wouldn't worry about your titers, just do the treatment.
Every new syphilis case must be tested for HIV.
Your HIV RNA test must be procedural, but, since your TPHA test was botched, there may be something wrong with the lab which did the initial round of testing. I strongly recommend retesting for HIV at a different lab, but always keep in mind that only antibody test (not RNA) is conclusive. I would do another DUO test instead in a few weeks and wouldn't hurry.
You definitely have an infection (syphilis) and it may influence your lymph nodes and CBC, so no need to worry much on that. Syphilis is associated with enlarged lymph nodes, all over the body too, when secondary stage starts.
Multiple small lesions on your genitals might be genital herpes, AuntieJesse would probably tell more on that.
I gave a blowjob and rimmed as well. I have an appointment with an infectious disease specialist and I’ll be sure to tell her I’d like to do a treponemal test again.