Hepatitis B, Hepatitis C, tuberculosis and sexually-transmitted infections among HIV positive patients in Kazakhstan

In contrast with global trends, HIV prevalence in Kazakhstan and other Central Asian countries has been rising in recent years. In this study, we analyzed hepatitis B (HBV), hepatitis C (HCV), tuberculosis (TB) and sexually-transmitted (STI) co-infections among 500 HIV positive study participants recruited from all regions of Kazakhstan. Among our study participants, 27%, 8%, 2%, and 5% were coinfected with, respectively, HCV, TB, HBV, and STI. A considerable proportion of the study participants was also found with triple or quadruple infections of HCV/TB (12%), TB/STI (0.8%), HCV/STI (2%), HCV/HBV (1%), HBV/TB (0.4%), HBV/STI (0.2%), HBV/HCV/TB (0.4%), HBV/HCV/STI (0.2%), or HCV/TB/STI (0.2%). Strong associations were found of certain age groups, duration of HIV infection, and practices of injection drug use and sexual contact with PLWH, with co-infections of HIV/HCV and HIV/TB. The odds of having death was 4.07 times higher with TB/HIV as compared to other co-infections. Co-occurrence of HIV with HCV, HBV, and TB infections among participants of this study highlights the necessity of regular screening for HCV infection among HIV infected patients, together with implementation of vigilant vaccination protocols against HBV and TB. Additionally, persons who inject drugs especially need to be focused for harm reduction efforts that include opiate substitution therapy, needle or syringe exchange programs, regular screening, and increased availability of ART and direct acting antivirals.

Association of various parameters with HCV/HIV co-infection was analyzed using Chi-square test and two-tailed t-test. We found a statistically significant association between HCV/HIV co-infection and the time of presentation, duration of HIV infection, and risk factors, being PWID and sexual contact with PLWH, and presence of STI history (p-value < 0.05) ( Table 1). Further, bivariate analysis revealed male sex to be a significant factor for co-infection (OR 8.05; CI 5. 35-12.11 Regarding STI/HIV co-infection, chi square test revealed that being PWID and the heterosexual route were significantly associated with STI co-infection (Table 1). Interestingly, bivariate analysis showed that the risk of STI co-infection was decreased by 65% (OR 0.35; CI 0.16-0.74) among participants, who acquired the HIV infection though injection drug use, compared to other modes of transmission (Supplementary Table 1). On the other hand, the multivariate analysis revealed no significant factor having an impact on STI/HIV co-infection.
Finally, assessing the effect of various types of co-infections on death status, the odds of having death among TB/HIV co-infected patients was 4.07 times higher compared to the rest of co-infections (OR 4.07; CI 1.99-8.27) (Fig. 3).

Discussion
In this study we analyzed 500 blood samples of HIV positive patients from all regions of Kazakhstan, for co-infections and their association with factors such as age, gender, risk behavior, duration of HIV infection, and travel.
Gender and age. Gender distribution among our study participants was 51% and 49% between, respectively males and female. Since 2003, the number of new HIV cases among women has been gradually increasing in Kazakhstan 13 . Compared to 60% PLWH reported to be male in 2010 14 and 2019 15 , our study found a shift in this proportion toward females. With respect to age, majority of patients in our study fell in 35-39y age-group (24%), followed by 40-44y (21%), and 30-34y (19%) (Fig. 1C) (Table 1), with cumulatively 64% of the patients falling between the ages 30-44y. According to the progress reports of Republican Center for Prevention and Control of AIDS in Kazakhstan, nowadays there is a transition dynamic in the age distribution of newly HIV infected patients. In 2001, 15% of the all new HIV cases belonged to 15-19y age group 16 . In 2005, the most severely affected age group was 20-29 years old (54%) 13 . In 2015, only 1.5% of newly infected HIV patients belong to  Geographical distribution. Our study group represented samples from 13 regions and 2 cities of Kazakhstan. The largest proportion (26%) of the HIV positive patients in our study was from Almaty region (Fig. 1B), which is also the most populated region of Kazakhstan, representing 21% of the country's population, comprising people of diverse origins and backgrounds. In other cases, however, the proportion of HIV positive patients did not align with the region/city population. Karaganda and Pavlodar, with, respectively, the second (21%) and third (13%) largest proportion of HIV patients are relatively smaller regions, constituting, respectively, 8% and 4% of the total population in Kazakhstan. This shows an overall high prevalence of HIV in these regions despite smaller numbers of overall inhabitants, owning possibly to particular high-risk practices.
High risk behavior. The most common mode of transmission among our study participants was through heterosexual sex (57%), followed by injection drug use (41%), and vertical transmission. This is in agreement with the recent trends: a 2019 study conducted with 12,953 participants found heterosexual transmission to be the most common (53%), followed by transmission through injection drug use (40%) and homosexual practice (3%) 15 . According to official statistics, as of 2011, the mode of HIV transmission has shifted from injection drug use to heterosexual sex 17 . Compared to 2006, when 20% infections were found associated with heterosexual contact, this percentage tripled to 67% in 2017 18 . The alarming aspect of this scenario is clearly the bridging of transmission from high-risk groups, such as PWID, to the general heterosexual population. Similar trends have been recorded in other former Soviet Union countries as well. In Russia, a 2019 study reported more than half (63%) of the HIV patients to have contracted the infection through heterosexual contact, compared to 34% acquiring the infection through injection drug use 19 . A downward trend has been noted in the injection drug use associated transmission: almost 70% in 2004, 60% in 2010, and 39% in 2018 20 . A similar trend has been reported in Uzbekistan 21,22 , where the transmission patterns have evolved in the past two decades among PWID and heterosexual populations with, respectively, 64% and 18% in 2005, 46% and 24% in 2008, and 41% and 42% in 2013 21 . In Ukraine, as well, while an almost equal distribution of transmission was reported among PWID and heterosexual populations in 2007, in 2018, this trend shifted to 30% and 48%, respectively 23,24 .

Co-infection with HCV, HBV, TB, and STI.
We found that in our study group 215 (43%) patients were HIV and HCV co-infected ( Fig. 2A). Among these PLWH, 136 (63%) were carrying double co-infection HIV/ HCV; 60 (28%) patients were infected with HIV/HCV/TB triple co-infection; 10 (5%) with HIV/HCV/STI; and 5 (2%) with HIV/HCV/HBV (Fig. 2B). Moreover, this study showed that HCV and HIV co-infection was predominant mostly among males aged 30-40y ( Table 1). The odds of being co-infected with HCV increased by 2 and 7.6 times for those infected with HIV for, respectively, 10-14y and 15-20y age groups. Our study revealed a significant association between co-infection with HCV and PWID population (Table 1). Globally, an estimated 2.3 million HIV/HCV co-infections are reported, with 1.4 million (59%) of them being PWID. Our finding is in agreement with recent studies showing that the prevalence of HCV co-infection among HIV-infected individuals was highest among PWID in Eastern Europe and Central Asia 25 . This can be due to the overlapping mode of transmission, namely, through needles, for HIV and HCV. In Kazakhstan, HIV/HCV co-infection has been on the rise among PWID 26 . In 2004, a study reported HCV co-infection among 97% HIV-positive patients, whereas that proportion was found to be 63% and 66% in 2005 and 2007, respectively 27 . In a relatively recent study in 2012, HCV co-infection among HIV positive patients was reported to be 53%-higher than, or similar to, the numbers reported from USA (30%), Thailand (50%), Eastern Europe (33%), and Russia (60%) 27 . Such high proportion of blood-borne virus infections in PWID clearly highlights a need for harm reduction efforts in this populations.  www.nature.com/scientificreports/ In our study group 4.2% of PLWH were co-infected with HBV ( Fig. 2A). Among these patients, 10 (48%) were diagnosed with double co-infection (HIV/HBV). Also, some participants were found to have triple or quadruple co-infections: 5 (24%) with HIV/HBV/HCV, 2 (9.5%) with HIV/HBV/TB, and 2 (9.5%) with HIV/ HBV/HCV/TB, 1 (4.8%) with HIV/HBV/STI, and 1 (4.8%) with HIV/HBV/STI/HCV (Fig. 2B). Since both HIV and HBV are transmitted by similar routes, i.e., sexually and through injection needles, HIV/HBV infection is common. Globally, 5-20% HIV-positive individuals are reported to be co-infected with HBV 28 , and our findings (4.2%) fall within that range. Since 2019 there were 19,300 registered cases of HBV reported in Kazakhstan 29 . However, due to the wide vaccination coverage number of HBV cases have been decreasing in the country. Over the past 25 years, the incidence of HBV among children and adults has decreased by, respectively,1234.5 and 32 times 30 . In our study, the most affected HIV/HBV age-group was 30-34y (7.4%), whereas no PLWH younger than 24y were diagnosed with HBV (Table 1). It has been reported that HBV co-infection in HIV infected people leads to a greater risk of liver disease progression 31 , increased mortality from AIDS-related events 28 , and poor HIV replication control with combination antiretroviral treatment 32 . Recent studies revealed the importance of employing sensitive biomarkers to identify HBV replicative activity in HIV-infected individuals who test anti-HBc-positive/HBsAg-negative 33 .
Among our study participants, 22% were found co-infected with HIV/TB ( Fig. 2A). The odds of TB/HIV co-infection among the study participants were highest among males, who had the HIV infection for 5-9 or 15-20 years. In addition, a significant association was found between PWID and TB/HIV co-infection (Table 1). Furthermore, our analysis showed that odds of death among TB/HIV co-infected individuals were 4 times higher relative to other types of co-infections (Fig. 3). In fact, co-infection with TB among HIV-infected population has been found to be the most common cause of HIV-related deaths 34 . According to WHO reports, TB is the most frequent life-threatening opportunistic infection among HIV/AIDS patients. TB co-infection is estimated to affect one-third of the world's HIV-positive population 35 . In HIV-infected people across the world, the prevalence of TB is around 30% 36 . In agreement with these figures, 22% of our HIV positive study participants were infected with TB.
Since 2005, there has been a gradual decrease in TB-associated morbidity and mortality levels in Kazakhstan, but still the country is among the ones, in the WHO European Region, with the highest TB incidence 37 . The probability that people living with HIV will be infected with an active form of tuberculosis is 20-30 times higher than that for HIV negative people 38 . In 2018 the population of Kazakhstan reached 18 million people with 13,361 registered cases of TB, and 730 (5%) coinfected with TB/HIV 39 . Impairment of immunity in HIV infected individuals exposes them to TB infection, with a 20-fold higher risk of reactivation of latent TB 40,] 41 . Further, susceptibility to TB infection might be increased among PWID due to limited access to health care, compromised housing conditions, overcrowding in places of injection, and poor adherence to treatment 42 .
Among our participants, 8% were co-infected with HIV/STI ( Fig. 2A). The most common STIs among participants were syphilis (3.2%), trichomoniasis (3%) and gonorrhea (1.4%). In this study being PWID was significantly associated with STI co-infection (Table 1). This might be due to the fact that PWID may frequently engage in risky sexual behaviors including sexual contact without protection or with multiple partners. According to the statistics of Kazakh Scientific Center of Dermatology and Infectious Diseases, incidence of STI has decreased by 34% between 2017 and 2018, including that of syphilis, gonorrhea, chlamydial infection and urogenital trichomoniasis 43 . MSM and PLWH are at the highest risk for syphilis, according to current surveillance data 44 . According to a comprehensive analysis of research completed across the world, syphilis is found among 9.5% of HIV-positive people 45 . Since both HIV and syphilis are sexually transmitted infections, individuals are frequently found co-infected with both. These viruses can be transferred through oral, vaginal, or anal mucosa 46 47 . While only 3.2% were co-infected with syphilis, compared to other STIs, the prevalence of syphilis among our study participants was the highest. In comparison, 3% of the participants were found co-infected with trichomoniasis. The global prevalence of these co-infections varies depending on the country 48 . Some studies highlight the significance of trichomoniasis in HIV positive people due to the potential role of trichomoniasis in increasing the risk of HIV transmission [48][49][50] . Among our study participants, co-infection of gonorrhea (1.4%) was to a lesser degree compared to what is globally reported. In the US, for instance, median point prevalence of HIV/gonorrhea co-infection is reported to be 9.5% 51 .
Socio-economics factors influencing access to healthcare. Overall there are 17 AIDS centers throughout the country, with one center per region. Kazakhstan, unlike most other former Soviet Union nations, allocates the budget for HIV treatment without the help of international contributors 52 . The Republican AIDS Center, Almaty, conducts quarterly monitoring and prevention programs carried out in the country, among key populations (PWID, RS, MSM), with the help of trust points (TP), friendly offices (FO), and non-governmental organizations (NGOs). The tools for monitoring and evaluation are electronic online systems of authorities and the National Database of Customers of Professional Programs 53 . Needle and syringe programs (NSPs) have played a critical role in containing the HIV pandemic across the world by offering HIV prevention information, syringes, and condoms to high-risk populations 54 . NSPs are widely available for PWID in Kazakhstan as well, with over 137 locations all over the country 18 . Moreover, since Kazakhstan is one of the nations affected most by the tuberculosis pandemic 55 , recently integrated approaches for TB and HIV care have been implemented, including that all patients infected with TB must be tested for HIV and vice versa 56 . Additionally, pregnant women are tested for HIV twice amid pregnancy, and there are no laws prohibiting PLWH from entering the country, while they are legally protected from discrimination 52  Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http:// creat iveco mmons. org/ licen ses/ by/4. 0/.