Herpes simplex virus type 2 in prisoners, New South Wales, Australia

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1 International Journal of STD & AIDS 2000; 11: 743± 747 ORIGINAL ARTICLE Herpes simplex virus type 2 in prisoners, New South Wales, Australia T Butler 1, B Donovan 2,3, J Taylor 4, A L Cunningham 4, A Mindel 5, M Levy 6 and J Kaldor 7 1 New South Wales Health Department, AIDS/Infectious Diseases Branch, NSW Health Department, North Sydney, NSW, Australia, 2 Sydney Sexual Health Centre, Sydney Hospital, 3 Department of Public Health and Community Medicine, University of Sydney, NSW, Australia, 4 Centre for Virus Research, Westmead Millennium Institute, NSW, Australia, 5 Academic Unit of Sexual Health Medicine, Sydney Hospital, NSW, Australia, 6New South Wales Corrections Health Service, NSW, Australia and 7 National Centre in HIV Epidemiology and Clinical Research, University of New South Wales, NSW, Australia Summary: Our objectives were to determine the prevalence of, and risk factors for, herpes simplex virus type 2 (HSV-2) antibodies in male and female prisoners. A cross-sectional random sample was used consisting of 789 prisoners (657 males and 132 females) from 27 correctional centres across New South Wales (NSW), strati ed by sex, age and Aboriginality. Participants were questioned about demographics and behavioural risk factors and were screened for serum antibody to HSV-2. The overall prevalence of HSV-2 antibodies was higher in females (58%) than males (21%), and in Aborigines (34%) compared with non-aborigines (24%). HSV-2 prevalence increased with the number of sexual partners. Few prisoners (1%) reported a previous diagnosis of genital herpes. Independent risk factors for the presence of HSV-2 antibodies were increasing age and Aboriginality for men, and higher reported number of lifetime sexual partners and the presence of hepatitis C antibodies for women. HSV-2 infection is common in prison inmates. There is a need to incorporate information about STDs, including HSV-2, into education programmes for inmates. Keywords: Prisoners, herpes simplex virus type 2, sexually transmitted diseases, indigenous INTRODUCTION Herpes simplex virus type 2 is one of the most common STDs and has been described as `the forgotten epidemic ; up to 45 million people in the USA are estimated to have the virus 1,2. The risk of HSV-2 infection has been linked to a number of demographic characteristics and sexual behaviours including age, sex (women greater than men), ethnic group (blacks greater than whites in the USA), age of rst sexual intercourse, lifetime number of sexual partners, and lower educational level 1. Several studies have found that individuals with HSV-2 antibodies are more likely to be human immunode ciency virus (HIV) antibody positive than those without HSV-2, and that HIV shedding in the genital tract is increased at the time of HSV reactivation 3. Previous studies have found prisoner populations to have high rates of syphilis and gonorrhoea, Correspondence to: Tony Butler. tbutler@one.net.au 743 but no previous studies appear to have examined the prevalence of HSV-2 4± 9. We therefore included screening for HSV-2 in a large-scale study of prisoners as they are often excluded by conventional community surveys. METHODS Study population and data collection As part of its strategy to improve the health status of the prisoner population, in 1996 the NSW Corrections Health Service and NSW Health Department conducted an extensive cross-sectional survey of prisoners, which included screening for a number of infectious diseases 10,11. Prisoners at 27 (24 male and 3 female) NSW correctional centres were invited to participate. Approval was granted independently by the NSW Corrections Health Research and Ethics Committee and the NSW Department of Corrective Services Institutional Ethics Committee. A strati ed random sample was chosen from the state s prisoner population on the basis of age, sex

2 744 International Journal of STD & AIDS Volume 11 November 2000 and Aboriginality, representing approximately 11% of all full-time male and 40% of full-time female prisoners. Those selected were invited to participate and briefed on the aims and objectives of the study. Only those who provided written consent were eligible to take part in the survey. Those refusing to participate were replaced from a reserve list until the required sample had been achieved. Each participant received $10 for taking part in the survey. Participants underwent a face-to-face interview using a standardized questionnaire covering physical and mental health issues. Information was collected on previous sexual activity, sexual activity in prison, and history of STDs. Subjects were also screened for a number of infectious diseases (HSV-2, syphilis, tuberculosis, HIV, rubella, hepatitis B, hepatitis C and hepatitis G) and a range of other health indicators (blood pressure, cholesterol and blood sugar level). Laboratory methods Glycoprotein G2 (gg2) puri ed by lectin af nity chromatography from HSV-2 infected cells was used in an indirect enzyme immunoassay (EIA) for the determination of HSV-2 type-speci c antibody 12. A 96-well EIA plate coated with gg2 antigen was incubated overnight and the unbound antigen washed off. A sample of human serum was added to the plate; any HSV-2 speci c antibodies bound to the antigen and the excess were washed off. An anti-human IgG/peroxidase conjugate which binds to these speci c antibodies was then added. The enzyme component of the bound conjugate produces a colour change on the addition of a chromogen. The reaction was stopped using acid and the intensity of the colour was measured by spectrophotometry and was proportional to the concentration of HSV-2 speci c antibodies in the sample 12. Western blot was used to resolve equivocal EIA results as described elsewhere 13. Table 1. Self-report of previously diagnosed STDs in New South Wales prisoners Males n=657 Females n=132 STD n (%) n (%) P value ± ± ± Pubic lice 125 (19.0) 13 (9.8) 0.01 Gonorrhoea 49 (7.5) 7 (5.3) ns Genital warts 31 (4.7) 12 (9.1) 0.06 Non-speci c urethritis 27 (4.1) Syphilis 24 (3.7) 6 (4.5) ns Chlamydia 9 (1.4) 10 (7.6) Genital herpes 6 (0.9) 4 (3.0) ns HIV* 2 (0.3) 2 (1.7) ns Note: multiple responses permitted *HIV results relate to serological screening conducted as part of the survey. ns=not signi cant Statistical methods Relationships were assessed using odds ratios (OR), calculated using SAS Univariate analysis was carried out on the relationship between exposure to HSV-2 in males and females and a range of demographic factors and possible behavioural risk factors. Variables with a signi - cance level of 0.2 or less in the univariate analysis were included in the multivariate model to assess those which were independently associated with HSV-2 antibodies. The Chi-square test and the Z test were used to assess associations between variables and differences in proportions, as appropriate. RESULTS Ð Ð A total of 789 prisoners participated in the survey (657 males and 132 females), including 235 Aborigines. The mean age was 33.8 years (SD= 12.4) for the men and 33.3 years (SD=10.5) for the women (t=0.4, P=0.7). Seven hundred and forty-seven of the 789 participants (95%) were screened for antibodies to HSV-2. Forty-two subjects were not tested for HSV- 2 because they refused to provide a blood sample, suitable veins for venepuncture could not be found, or insuf cient blood was obtained to conduct the test. The response rate to the survey was 90%. Nonresponders were classi ed as: (1) `refusers those who atly refused to participate, and (2) `unavailable those who were engaged in an activity preventing participation. Some of the reasons cited by the `refusers included: dislike of needles, and imminent release therefore no point taking part. For the `unavailable group reasons were: court appearances, security classi cation interviews, transfers to other gaols, considered as `too dangerous by custodial staff, didn t want to leave their work, deported from Australia, and attending a funeral. There were 74 male and 15 female `refusers and 181 males and 28 females who were `unavailable to take part in the survey. The unavailable group were excluded from the response rate calculation. Of the 747 subjects tested for HSV-2, 27% (201/747) were positive for antibodies. The prevalence of HSV-2 antibodies was 21% (133/ 629) in males and 58% (68/118) in females (P<0.0001). HSV-2 positives were older than seronegatives (36.0 years cf 32.4 years; P<0.001). The prevalence of HSV-2 was higher in Aborigines compared with non-aborigines (34% cf 24%; P<0.01). Roughly equal proportions of males and females had been previously diagnosed with an STD (28% cf 32%; P=0.5), with pubic lice being the most common in both sexes (Table 1). Only 10 subjects reported a past history of genital herpes, of whom 9

3 Butler et al. HSV-2 in prisoners in NSW, Australia 745 Figure 1. HSV-2 prevalence and self-reported lifetime number of sexual partners in female inmates Figure 2. HSV-2 prevalence and self-reported lifetime number of sexual partners in male inmates were screened for HSV-2 antibodies and all but one (8/9) tested positive. There was a signi cant association between gender and the lifetime number of sexual partners (w 2 =67.2, P=0.001). For each category of partner numbers, the prevalence of HSV-2 was between 2 and 3 times higher in females compared with males (Figures 1 and 2). The prevalence of HSV-2 in females reporting more than 100 sexual partners was 92% compared with 38% in the male group. In the univariate analysis, factors associated with a signi cant increase in risk of HSV-2 in males were being in the age group 25± 40 years (OR=2.9, 95% CI=1.7± 5.0, P=0.0001), age over 40 (OR=2.3, 95% CI= 1.5± 3.4, P=0.001), Aboriginality (OR=1.8, 95% CI=1.2± 2.6, P= 0.005), over 20 sexual partners (OR=1.7, 95% CI=1.1± 2.5, P=0.02), a history of STDs (OR=2.0, 95% CI=1.4± 3.0, P=0.001), and testing positive for the hepatitis B antibody (OR=1.8, 95% CI=1.2± 2.7, P=0.003). An education level of a school certi cate or trade quali cation was associated with a signi cantly reduced risk of HSV-2 in males (OR=0.7, 95% CI=0.4± 1.0, P=0.05). For females, factors associated with an increased risk of HSV-2 were Aboriginality (OR=3.8, 95% CI=1.4± 10.1, P=0.01), testing positive for the hepatitis B antibody (OR=2.7, 95% CI=1.3± 5.8, P=0.01), testing positive for the hepatitis C antibody (OR=3.8, 95% CI= 1.7± 8.5, P=0.001), and over 20 sexual partners (OR=4.0, 95% CI=1.3± 11.9, P=0.01). Using condoms occasionally or never was associated with a signi cant decrease in risk for HSV-2 in females (OR=0.3, 95% CI=0.1± 0.9, P=0.03). In the multivariate analysis, only age and Aboriginality persisted as signi cant predictors of HSV-2 in males (Table 2). In females, having over 20 lifetime sexual partners and the presence of antibodies to hepatitis C were the only factors associated with HSV-2 (Table 2). DISCUSSION In the prisoner population we examined, the prevalence of HSV-2 was much higher in females Table 2. Adjusted odds ratios for risk factors associated with HSV-2 infection in male and female prisoners Males Females Risk factor OR P value 95% CI OR P value 95% CI Age (years) < ± ± ± ± ± 16.5 Aborigine No Yes ± ± 5.8 Lifetime sexual partners > ± ± 11.7 Hepatitis B core antibody No Yes ± ± 6.3 Hepatitis C antibody No 1.0 Yes ± 14.0 OR=odds ratio; CI=con dence intervals

4 746 International Journal of STD & AIDS Volume 11 November 2000 (58%) than males (21%), probably re ecting the greater ef ciency of male-to-female transmission 15. The prevalence of HSV-2 was higher in Aboriginal men; in the US, prevalence has been found to be higher among African± American and Mexican± American men than among white men 2. Prevalence estimates of HSV-2 vary depending on the study population and country; a Sydney study conducted in the mid-1980s found the prevalence in STD clinic attendees to be 35% in males and 55% in females, and 14.5% in an antenatal population 16. By 1990/91, 65% of heterosexual males presenting to a Sydney STD clinic were HSV-2 positive, with approximately one-third reporting a history of genital herpes 24. Within the sample studied, HSV-2 antibody prevalence increased with age and the lifetime number of sexual partners, implying that the risk of HSV-2 infection is cumulative. Previous studies have suggested that because it is so common, the presence of HSV-2 antibody may be a useful measure of sexual lifestyle within populations and could be used to assess changes in behaviour 17,18. Ninety-two per cent of females reporting over 100 lifetime sexual partners were positive for HSV- 2 antibodies which is comparable with levels observed in African and Asian prostitute populations 19± 21. Although we did not ask speci cally if women had engaged in sex work, of the 12 females who reported over 100 lifetime sexual partners, 11 were injecting drug users and were also positive for hepatitis C antibody. It is likely that some of this group of women have been sex workers at some point and could explain the high proportion of HSV-2 seropositives. We cannot explain the association found between HSV-2 and hepatitis C antibodies in women other than to suspect that the relationship may be confounded. In this cross-sectional study, condom use was not found to be protective against HSV-2, which is consistent with a previous nding showing that in a population with a large number of sexual partners condoms are not necessarily protective against HSV Many of the HSV-2 infections we detected could have pre-dated the reported pattern of condom use and the use of condoms may have been a marker of selecting higher-risk sexual partners. Nevertheless, as condoms do not cover all of the parts of the anatomy that could be affected by HSV-2 infection we would expect that any protection provided by condoms would be limited. Only a well-designed longitudinal study could determine the level of protection. Only 1% of those who tested seropositive for HSV-2 antibodies reported a history of being diagnosed with genital herpes, a much lower proportion than has been found in other studies 22± 24. Community-derived or population-based samples typically nd that about 11± 27% of HSV-2 seropositives have been previously diagnosed. A partial explanation for our nding could be that a high background level of prior HSV-1 infection could have moderated the clinical expression of HSV-2 infection. As we did not screen for antibodies to HSV-1 we were unable to test this hypothesis. Possibly, and more importantly, this may be a group who are relatively unaware of the self-limiting nature of the symptoms of genital herpes, compounded by relatively limited access to health services outside prison. Notably, indigenous people are rarely diagnosed with clinical genital herpes in NSW (Dr C Bourne, Far Western Area Health Service; Dr D Plummer, Macquarie Area Health Service; personal communications). We did not enquire speci cally about symptoms suggestive of genital herpes. The information we collected on sexual behaviours is subject to the vagaries of self-report; however, these data are consistent with previous ndings on prisoner populations; for example the proportion of inmates reporting injecting drug use. We found no association between homosexuality/ bisexuality and HSV-2, which may be due to poor self-report with regard to this question. Strengths of the current study include the selection of subjects using a multi-site random sample rather than focusing on a population seeking treatment, and the use of trained interviewers who were experienced in dealing with this client group. Transmission of HSV-2 within prisons needs to be considered given that homosexual and heterosexual sexual activity is known to continue for some inmates 25± 27. The issues of inmate rape and sexual favours have also been identi ed in prisoner populations; however these remain taboo subjects for prison authorities and are poorly researched 28,29. Further work is needed to assess the potential for the transmission of HSV-2 and other STDs within NSW prisons. Whilst these data cannot be generalized to the Australian community as a whole, they do provide estimates for a marginalized group in society who are often overlooked in community surveys. They also provide prevalence estimates which allow comparisons to be made with other groups such as STD clinic attendees and antenatal populations. Until a vaccine is developed, education may be the most effective means of reducing the further spread of HSV-2. Prisons represent an ideal public health opportunity in which to intervene and provide education to this group about STDs and their transmission. Acknowledgements: We wish to thank the NSW Corrections Health Service and the NSW Health Department for providing nancial support for the project; the Department of Corrective Services for granting permission to conduct the survey; the interviewers who were involved in collecting blood specimens and interviewing the inmates; and Carolyn Seifert for assistance with the HSV-2 testing.

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