Among PLHIV who were newly diagnosed at the largest HIV testing center in Bangkok, we found 6% prevalence of HBV and 4% prevalence of anti-HCV positivity. Being MSM, TGW, and born before the inclusion of universal hepatitis B vaccination in Thailand’s EPI were associated with HBV infection. Moreover, being MSM and having syphilis increased the chance of being anti-HCV positive.
More than 70% of our population were MSM, and 5% were TGW, reflecting proportions of new HIV infections in Thailand as projected by the AIDS Epidemic Model [21]. We found the HBV prevalence to be highest among TGW (9%), followed by MSM (6%). The anti-HCV seroprevalence was highest among MSM (5%), followed by TGW (4%). These data confirmed findings from previous studies which demonstrated higher prevalence rates of HBV and HCV among PLHIV who were MSM and TGW than those who were general population [1, 15, 22–25]. The HBV prevalence shown in our population is quite concerning as almost half of them were born after EPI, indicating that the HBV epidemic is still ongoing. Nevertheless, the prevalence of HBV and HCV found in our study were slightly lower than that of the global and Thai reports among PLHIV [1, 2, 5], likely due to the younger age of our population. Apart from viral hepatitis, almost 20% of our clients had syphilis at baseline, showing higher burden than what was reported in general MSM population by World Health Organization (WHO; 6%) in 2018 [26].
MSM and TGW had 1.6 and 2.9 times higher odds of HBV infection than the general population, respectively, which could be explained by sexual practices and routes which are more prone to mechanical trauma [27]. Consistent with the national survey [17], we saw a contrast of HBV prevalence between people who were born before and after EPI (8% vs. 4%). PLHIV who were born before EPI had 2.3 times higher odds of having HBV infection. Another explanation of the association to birth year would be that younger people had less time exposed to the infection than older people. Nonetheless, this study exhibited that HBV infection was not completely eliminated by the EPI. Some newborns might be born to an HBV-infected mother, not complete the full course of the immunization, not respond to HBV vaccination, or be unvaccinated. Regarding PLHIV who do not have immunity to HBV, it is advised to immunize all PLHIV regardless of CD4 level [18], even though the lower CD4 count is one of the factors affecting the effectiveness of the HBV immunization [28–30].
We found that being MSM and having syphilis each increases the risk of having positive anti-HCV by around two times in our study. There are many reports of the HCV epidemic among MSM living with HIV in major cities of the world in Europe, Asia-Pacific, and Thailand [8–10, 31–37], and many findings demonstrated an upward trend of HCV infection [9, 31–37]. For example, a study in Thailand found that HCV incidence increased from 0.7–1.1 per 100 person-years in 2014–2016 to 4.5 per 100 person-years in 2018 [31]. HCV infection is widely known as associated with recreational drug use [9, 10, 31, 32, 36, 38–41], as some MSM utilize recreational drugs to improve their sexual pleasure, so-called chemsex [43, 44]. Studies on people who did not use injection drugs found that HCV infection was still associated with recreational drug use and syphilis [34, 36, 45], suggesting transmission of HCV associated with sexual encounter. Unfortunately, we did not collect data on substance use and chemsex systematically in our study and could not look at these potential associations. However, as MSM and syphilis were key factors associated with HCV infection among our clients, we hypothesized that HCV acquisition in our HIV-positive MSM population was likely linked to sexual transmission and possibly in the chemsex context.
There were a few limitations in this study. This study was conducted at one site and two-thirds of our PLHIV clients lived in Bangkok. Thus, our study population might not represent the overall population of PLHIV in Thailand. We could not retrieve hepatitis B vaccination history from original medical records, and therefore needed to use PLHIV clients’ birth year as a surrogate. We did not record substance use and chemsex data and could not explore their associations with HBV and HCV infections in our study. Lastly, we did not perform HCV RNA in anti-HCV-positive clients; therefore, the observed anti-HCV seroprevalence may be higher than the actual infection rate.
WHO aimed to eliminate hepatitis B and C infections by 2030 [46]. To achieve this, a country must target the areas determined to have beneficial impacts as described in Table 5 [46, 47]. In Thailand, HBV vaccination has reached 95% coverage since 1999 [17]. However, Thailand’s diagnosis and treatment coverage of HBV and HCV are far from the target [47]. From the results of this study, HBV and HCV screening of everyone living with HIV regardless of age would uncover a high proportion of undiagnosed infections and be a chance to bring them to treatment. Testing more undiagnosed PLHIV would also bring in more undiagnosed people living with HBV and HCV. PLHIV without HBV infection should be assessed for the need of HBV vaccination or booster. Costs of HCV genotyping and treatment have been high, but the voluntary licensing of pan-genotypic direct-acting antiretroviral (DAA) medications is becoming implemented in Thailand [48]. However, the current restriction to only start DAA in individuals with fibrosis METAVIR Stage F2 means that individuals with HCV can continue to transmit the virus to others. Future studies will need to explore strategies to timely and efficiently test and treat HCV, especially among PLHIV, to contribute to the elimination of HCV.
Table 5
Global Baseline and Thailand’s Progress Toward the Elimination of Hepatitis B and C by 2030
Target Area | Global Baseline 2015 | Thailand Estimates 2019 | WHO Target 2030 |
HBV birth dose | 38% | 99% | 90% |
HBV 3 + doses | 82% | 97% | 90% |
Blood safety | 89% | 100% | 100% |
Injection safety | 5% | 100% | 90% |
Syringes per PWID† | 20 | 24 | 300 |
HBV diagnosed | < 5% | 7% | 90% |
HBV treated | < 1% | 1% | 80% |
HCV diagnosed | < 5% | 36% | 90% |
HCV treated | < 1% | 11% | 80% |
WHO, World Health Organization; HBV, hepatitis B virus; PWID, person who injects drugs; HCV, hepatitis C virus |
†Number of sterile needles and syringes provided per person who injects drugs per year |