Thank you

You needn't worry. Although doxycycline has not been as rigorously studied for its effectiveness in treating syphilis as penicillin has, it is generally accepted by all syphilis experts as equally effective. The main problem, i.e. the most important reason it isn't used as frequently as penicillin, is compliance:  many people have trouble sticking to twice daily antibiotic treatment for 2-4 weeks (depending on syphilis stage), whereas penicillin has the advantage of having long acting forms that can provide prolonged blood levels for 10 days after a single dose, i.e. can accomplish the goal of 4 weeks treatment with just 3 shots.

And as you seem to know, the decline in your VDRL titer is in the range that is generally considered to indicate complete cure. As for your baby, for sure no risk there:  after such treatment, and with your VDRL remaining no higher than 1:2, there is no realistic chance you could have infected your child. That said, I'm a bit surprised your child's ObG (or her pediatrician, if aware of your history) did not test her at age 6 months. (Up til then, she could have had a positve result because of your own positive test.) The chance she was infected was zero or very close to it, but still such testing normally would have been recommended.

That's the good news. But there is a slight shadow. Presumably the duration of your syphilis when diagnosed was believed to be a year or more. (If under a year, only 2 weeks of doxycycline would have been recommended.) For all syphilis more than a year in duration, or of unknown duration, a lumbar puncture (spinal tap) is recommended to assure there is no asymptomatic central nervous system infection (i.e. neurosyphilis). Presumably this wasn't done or you would have said so. The problem is that doxycycline is NOT advised for neurosyphilis. It might work, but there are no data -- had you had abnormal spinal fluid, you would have been given penicillin despite your penicillin allergy (perhaps with desensitization to reduce the risk of a reaction). OTOH, your VDRL titer declined appropriately, so it is very unlikely you had neurosyphilis.

There are no solid data to know how long you should continue to have annual testing. But my inclination would be to continue it a few more years, just to be maximally safe. I imagine it might be somewhat anxiety producing every time you do it, but it sounds like you have a level headed, rational attitude about it all. And you might find your VDRL becomes even less reactive or altogether negative -- which you probably would like!

Going back to your daughter, for the reasons above, there is no significant chance she was infected. However, one of the reasons you came to the forum is that you're obviously a bit worried about it. For reassurance purposes, consider telling this story to her pediatriican and request she be tested. Almost certainly the result will be negative, and you'll breathe a sigh of relief -- which should make it worthwhile, right? If uncertain about approaching the pediatrician, consider printing out this thread as a framework for discussion.

Finally, you may know that even in the very slight chance you still have a latent, incompletely resolved syphlis infection, you are not infectious for others. Beyond a year, and following treatment, syphilis is not sexually transmitted, and rarely if ever to babies prior to delivery. So no matter what else, your husband/partner (or future sex partners) and/or future children are not at risk.

I hope this information is helpful to you. Let me know if anything isn't clear.

Regards--  HHH, MD

Thank you! 

You husband's situation is a bit more concerning. Although in one way he meets accepted criteria for cure (a 2 dilution decline in VDRL titer), usually the titer declines to well be low 1:8, such as 1:2 or lower. So a case could be made for him to have an LP and, if his CSF is normal, to receive 3 doses of long acting (benzathine) penicillin.

Do you think he was compliant with doxycycline, i.e. missed few if any doses?

One approach to all this would be fo make an appointment for the entire family with an infectious diseases specialist -- or even better, one who specializes primarily in STDs. Then follow her or his advice for all three of you.

I'm curious where your and your husband's syphilis was diagnosed? City and country?

Me do not provide direct medical advice; I am not your husband's doctor and I have said as much as I can about it. Many factors based on physical examination and detailed medical history must go into a decision for or against further diagnosis or treatment of syphilis, including LP. He should discuss his situation with his doctor; or, even better, an infectious diseases or STD expert.

That completes the two follow-up comments and replies included with each question, and so ends this thread. Best wishes to you and your family.