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Background:  A strong epidemiological association has been observed between HIV and herpes simplex virus (HSV)-2 infection. The aim of this study was to investigate HSV-2 seroprevalence at HIV diagnosis and seroincidence after HIV diagnosis, and the associated risk factors, in an ethnically diverse cohort of HIV-seropositive persons.

Methods:  We tested 850 sera collected at the time of HIV diagnosis for HSV type-specific antibodies by EIA. Positive results were confirmed by immunoblot and by inhibition enzyme immunoassay 9EIA0. Sera from 123 patients who were HSV-2 sero-negative at HIV diagnosis were tested to assess HSV-2 sero-incidence at ≥ 1 year after HIV diagnosis.

Results:  The cohort included 534 (63%) males; 467 (55%) heterosexuals; 385 (45%) black Africans; 371 (43%) whites; and 83 (10%) black Caribbeans. HSV-1 and 2 sero-prevalence at HIV diagnosis were 88.5% and 63%, respectively. HSV-2 sero-positivity at HIV diagnosis was significantly associated with female gender (p = 0.0001), heterosexual risk group (p = 0.0001), black ethnicity (p = 0.0001) and older age (p = 0.01). Over a median 8 years of follow up (range 1 to 16 years), among 123 individuals who were initially HSV-2 seronegative, 10% seroconverted for HSV-2 antibodies. In addition, 32% received a diagnosis of HPV infection, 11% had gonorrhoea, 5% had chlamydia, and 2% had syphilis. HSV-2 seroconversion was significantly associated with a diagnosis of HPV infection (p = 0.005) and gonorrhoea (p = 0.05). Over the same period of follow up, 22% HSV-2 sero-positive patients received a clinical diagnosis of genital herpes, but only 14% had an HSV-2 positive genital swab by virus culture. A clinical diagnosis of genital herpes (p = 0.0001) and an HSV-2 positive swab (p = 0.0008) was 4 times more likely in patients diagnosed HIV sero-positive before 1997.

Conclusions:  HSV-2 prevalence is high among HIV-infected persons at the time of HIV diagnosis, confirming the strong epidemiological association between HIV and HSV-2. However the majority of HSV-2 infections remain undiagnosed by routine clinical care. Since the introduction of highly exposed persistently seronegative symptomatic HSV-2 infection occurs less commonly in HIV-infected patients. HSV-2 seroconversion after HIV diagnosis is associated with the acquisition of other STDs and is therefore a marker of high-risk sexual behavior.

Keywords: HSV-2; STD; Incidence