Can Syphilis Test Results Ever Be Zero? Transmission Risks

Q: Can Syphilis Test Results Ever Be Zero? Transmission Risks

Dear readers： <br><Can the index for syphilis be zero?> The response is as follows： According to the data from the Centers for Disease Control (CDC) (see attachment) on page 5, the case definition for reporting conditions is as follows：<br>1. <br>Clinical conditions：<br> (1) Th

Can the syphilis index be zero?

I would like to ask, if I only have a positive TPHA and negative RPR or VDRL, can I still transmit the infection to others? The test was conducted two years ago, and I received treatment at that time.
This year, during follow-up, my titers have decreased significantly to 1:2 or 1:1.
The doctor mentioned that it is now very safe and that I do not need to take medication as it will naturally decline.
I learned that once I have tested positive, I will always show positive results in blood tests, but future monitoring will focus on the titers.
A decrease in titers indicates improvement, but I have heard that it is not possible for the titers to reach zero.
However, I also read that some people claim that after two to three years, the titers can naturally reach zero.
So, what is the truth? I am asking because I am concerned that if I have a steady partner in the future, I cannot use protection forever, and I am worried about transmitting the infection to them.
Given that my titers are consistently decreasing and my partner is also uninfected, can I still transmit the infection to them?

M, 20~29 year old female. Ask Date: 2017/07/03

Dr. Liao Zhongxin reply Internal Medicine

Dear readers:
The response is as follows: According to the data from the Centers for Disease Control (CDC) (see attachment) on page 5, the case definition for reporting conditions is as follows:
1.
Clinical conditions:
(1) The presence of primary syphilis clinical symptoms, such as painless ulcers or hard chancres.
(2) The presence of secondary syphilis clinical symptoms, such as generalized syphilitic rash, generalized lymphadenopathy, fever, headache, fatigue, pharyngitis, muscle and joint pain, alopecia, and flat warts.
(3) The presence of tertiary syphilis clinical symptoms, such as skin gummas, cardiovascular syphilis, or neurosyphilis.
2.
Testing conditions, meeting any of the following criteria:
(1) Individuals who have never received syphilis treatment or have unclear medical history, with positive results on both non-treponemal tests and treponemal tests.
(2) Clinical specimens (such as exudate from lesions or tissues) tested for Treponema pallidum using darkfield microscopy, fluorescent antibody testing, or nucleic acid testing.
(3) Positive results from cerebrospinal fluid venereal disease research laboratory tests (CSF-VDRL).
(4) Individuals who have previously received syphilis treatment, with a fourfold increase in the titer of non-treponemal tests.
Based on past experiences:
1.
In the acute phase (immediately after infection), the index is usually higher, e.g., RPR > 1:16.
After timely and effective treatment, the index generally decreases, often to 1:1X to 1:2X, or even shows a negative response.
2.
In the chronic phase (lasting more than a year), even after treatment, the RPR index decreases slowly or may remain unchanged.
3.
Generally, after an effective treatment course, even if the index does not show significant decline, the individual is considered non-infectious.
4.
If the RPR value suddenly increases by fourfold or more, it should be considered a reinfection, and another effective treatment course should be undertaken.
Thank you!

Reply Date: 2017/07/03

More Info

When it comes to syphilis testing, understanding the nuances of the results is crucial for both your health and the health of your partners. In your case, you mentioned having a positive TPHA (Treponema pallidum hemagglutination assay) and negative RPR (Rapid Plasma Reagin) or VDRL (Venereal Disease Research Laboratory) tests. This situation raises several important points regarding syphilis transmission and the interpretation of test results.

Firstly, it's essential to understand that the TPHA test is a specific test for syphilis, which detects antibodies against the Treponema pallidum bacterium, the causative agent of syphilis. A positive TPHA indicates that you have been exposed to the syphilis bacteria at some point. However, the RPR and VDRL tests are non-treponemal tests that are used for screening and monitoring treatment response. These tests can yield false positives and are less specific than the TPHA test.

In your case, the fact that your RPR or VDRL tests are negative suggests that you may not currently have an active syphilis infection, especially if you have received treatment in the past. The decline in your RPR titer (from higher values to 1:2 or 1:1) indicates that your body is clearing the infection, which is a positive sign. Generally, a significant drop in RPR titers after treatment is a good indicator of treatment success.

Regarding your concern about transmission: if your RPR and VDRL tests are negative, and you are not experiencing any symptoms of syphilis, the risk of transmitting syphilis to a partner is significantly reduced. However, it is important to note that the TPHA test can remain positive for life, even after successful treatment. This means that while you may not be infectious, the positive TPHA result does not necessarily indicate an active infection.

As for the possibility of the RPR or VDRL results returning to zero, it is uncommon for these tests to become completely negative after treatment, especially if they were initially positive. However, a significant decrease in titers, as you have experienced, is a good sign. It is also important to continue regular follow-ups with your healthcare provider to monitor your status and ensure that you remain free of syphilis.

If you are considering entering into a new relationship, it is essential to communicate openly with your partner about your past syphilis infection and your current test results. While your current tests indicate a low risk of transmission, it is always wise to practice safe sex, including the use of condoms, to protect both yourself and your partner from any potential infections.

In summary, while a positive TPHA indicates past exposure to syphilis, negative RPR and VDRL tests suggest that you are not currently infectious. Regular follow-ups and open communication with partners are key to managing your sexual health. If you have any further concerns or questions, don't hesitate to reach out to your healthcare provider for personalized advice.

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