Date du document : 05/10/2023
Date de mise en ligne : 05/11/2023
The High Council of Public Health (HCSP) is questioned about the existence of biological tests for determining that a person has been cured of syphilis for at least one year, in the hope of reintegrating them into the transfusion chain, as mentioned in Directive 2002/98/EC concerning certain technical requirements related to blood and blood components. The biological tests used to qualify blood donations are treponemal tests (TT) that detect antibodies directed against the bacterium responsible for syphilis. These antibodies are present well beyond one year, even if the person is cured. There are also non-treponemal tests (NTT) which detect anti-cardiolipidic antibodies during infection. TNTs have the advantage of being positive in the acute phase of the disease and becoming negative again in the case of treated and cured syphilis. However, TNTs can remain negative for up to 6 weeks after the start of infection and the stage of infection cannot be determined without anamnestic or clinical context. There are also many cases of reinfection, syphilis not being an immunizing disease, as well as false positive results. The result is that no robust biological indicator makes it possible to distinguish recent syphilis from serological sequel in the absence of a clinical context. Furthermore, the HCSP questioned the European blood alliance to find out the practices in force in other European countries: the 13 countries that responded definitively exclude donors presenting biological stigmata of confirmed syphilis. Considering these elements and the primary need to preserve the safety of recipients, the HCSP recommends maintaining the definitive exclusion of candidates for blood donation as long as they are or have been confirmed positive by the presence of anti-syphilis antibodies. He also recalls the importance of filling out the pre-donation questionnaire very accurately, particularly in terms of sexual behavior, because TT can be negative at the very early phase of the primary infection.
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