Use of the Serologic Testing Algorithm for Recent HIV
Use of the Serologic Testing Algorithm for Recent HIV
Background: Syphilis outbreaks among men who have sex with men (MSM) in the United States, many of whom are HIV infected, have prompted increased concern for HIV transmission.
Methods: To identify whether men are acquiring HIV concomitantly or within the critical period of syphilis infection, banked Treponema pallidum particle agglutination-positive serum specimens from men with early syphilis infection were screened for HIV-1 antibody. Samples that were positive for HIV antibody were then tested with a less sensitive (LS) HIV-1 antibody enzyme immunoassay (serologic testing algorithm for recent HIV seroconversion [STARHS]) to identify HIV infections that occurred on average within the previous 6 months.
Results: Of the 212 specimens banked from men with early syphilis, 74 (35%) were HIV-positive. Of these, 15 tested non-reactive by the LS assay. Twelve of these 15 were considered to be recent infections by the LS assay and testing history. Eleven (92%) of the recent infections were among MSM. One man had primary syphilis, 6 (50%) had secondary syphilis, and 5 (42%) had early latent syphilis. Eight men (67%) reported sex with anonymous partners, and 3 (25%) reported consistent condom use. The estimated HIV incidence was 17% per year (95% confidence interval [CI]: 12%-22%) among all men with early syphilis, and it was 26% per year (95% CI: 91%-33%) among MSM.
Conclusions: Syphilis epidemics in MSM may be contributing to HIV incidence in this population. The STARHS can be applied as a surveillance tool to assess HIV incidence in various at-risk populations, but further studies are necessary for validation.
The reported number of HIV diagnoses increased in 29 states from 1999 to 2002, with a 17% increase documented among men who have sex with men (MSM), suggesting a possible resurgence of HIV transmission in this at-risk group. There are an estimated 45,000 persons living with HIV and AIDS in Los Angeles County (LAC) who are aware of their status and an estimated 9000 persons with HIV who do not know their status. As of December 2003, the epidemic of HIV/AIDS in LAC remains predominantly among males (89%), people of color (63%), and MSM (70%).
A concurrent epidemic of syphilis among MSM has been ongoing in LAC since early 2000. During 2003, 704 cases of early syphilis were diagnosed in LAC, with 464 (66%) occurring among MSM. HIV-seropositive men made up 60% of these early syphilis cases diagnosed among MSM. These coinfection rates are of significant concern, given the increased risk of HIV transmission associated with a sexually transmitted disease (STD) such as syphilis. Recently reported data among MSM diagnosed with incident HIV and an STD in San Francisco support this risk. In addition, reports of increases in unsafe sexual behaviors among MSM groups suggest further transmission opportunities for HIV and other STDs in these populations.
To evaluate the contribution of the ongoing syphilis epidemic to incident HIV infections among MSM, we applied STARHS to stored blood specimens of men diagnosed with early syphilis.
Background: Syphilis outbreaks among men who have sex with men (MSM) in the United States, many of whom are HIV infected, have prompted increased concern for HIV transmission.
Methods: To identify whether men are acquiring HIV concomitantly or within the critical period of syphilis infection, banked Treponema pallidum particle agglutination-positive serum specimens from men with early syphilis infection were screened for HIV-1 antibody. Samples that were positive for HIV antibody were then tested with a less sensitive (LS) HIV-1 antibody enzyme immunoassay (serologic testing algorithm for recent HIV seroconversion [STARHS]) to identify HIV infections that occurred on average within the previous 6 months.
Results: Of the 212 specimens banked from men with early syphilis, 74 (35%) were HIV-positive. Of these, 15 tested non-reactive by the LS assay. Twelve of these 15 were considered to be recent infections by the LS assay and testing history. Eleven (92%) of the recent infections were among MSM. One man had primary syphilis, 6 (50%) had secondary syphilis, and 5 (42%) had early latent syphilis. Eight men (67%) reported sex with anonymous partners, and 3 (25%) reported consistent condom use. The estimated HIV incidence was 17% per year (95% confidence interval [CI]: 12%-22%) among all men with early syphilis, and it was 26% per year (95% CI: 91%-33%) among MSM.
Conclusions: Syphilis epidemics in MSM may be contributing to HIV incidence in this population. The STARHS can be applied as a surveillance tool to assess HIV incidence in various at-risk populations, but further studies are necessary for validation.
The reported number of HIV diagnoses increased in 29 states from 1999 to 2002, with a 17% increase documented among men who have sex with men (MSM), suggesting a possible resurgence of HIV transmission in this at-risk group. There are an estimated 45,000 persons living with HIV and AIDS in Los Angeles County (LAC) who are aware of their status and an estimated 9000 persons with HIV who do not know their status. As of December 2003, the epidemic of HIV/AIDS in LAC remains predominantly among males (89%), people of color (63%), and MSM (70%).
A concurrent epidemic of syphilis among MSM has been ongoing in LAC since early 2000. During 2003, 704 cases of early syphilis were diagnosed in LAC, with 464 (66%) occurring among MSM. HIV-seropositive men made up 60% of these early syphilis cases diagnosed among MSM. These coinfection rates are of significant concern, given the increased risk of HIV transmission associated with a sexually transmitted disease (STD) such as syphilis. Recently reported data among MSM diagnosed with incident HIV and an STD in San Francisco support this risk. In addition, reports of increases in unsafe sexual behaviors among MSM groups suggest further transmission opportunities for HIV and other STDs in these populations.
To evaluate the contribution of the ongoing syphilis epidemic to incident HIV infections among MSM, we applied STARHS to stored blood specimens of men diagnosed with early syphilis.
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