The case control study was part of a larger, longitudinal study of risk factors for HIV, and in the analysis, researchers compared vaginal samples from women who acquired HIV during the course of the study to matched controls. At the visit before seroconversion, mycoplasma infections were more than twice as common among the women who acquired HIV compared to a similar visit for women who remained HIV negative throughout the study. However, it is worth noting that there is no data, yet, to say that this relationship was causal. Women who became HIV positive over the course of the study also had higher rates of genital herpes, gonorrhea, and trichomoniasis at baseline, and gonorrhea and herpes were both significantly more common in HIV+ women than controls at the time they seroconverted. Therefore, although there are biological reasons to believe that mycoplasma might physically increase HIV risk, it may also be a marker for sexual activity or other infection.
Hopefully further research will clarify the association between mycoplasma and HIV and establish whether testing for this bacterium should become routine.