Abstract
Objectives
People who inject drugs (PWID) are central to the HIV epidemic in Vietnam, many delay HIV testing and antiretroviral therapy (ART) until advanced disease. We assessed prevalence and correlates of ART use and low CD4 counts among PWID with HIV.
Setting
Analysis of the 2013 Integrated Behavioral and Biologic Survey in Vietnam.
Methods
Eligible participants were men aged ≥ 18 years who reported recent injecting, were HIV positive, and consented to future viral load (VL) and CD4 testing. Undetectable VL was defined as < 50 copies/ml. Percentages and prevalences were adjusted for sampling method.
Results
Of 287 PWID, 55% knew their status. Among these, 88% were on ART, and 82% had undetectable VL. ART use was positively associated with older age (> 40 vs. < 30 years, OR 4.9, 95% CI 1.2–20.5) and opioid substitution therapy (OR 12.7, 95% CI 1.1–141.7). It was negatively associated with living alone (OR 0.1, 95% CI 0.0–0.5), living with a partner versus relatives (OR 0.3, 95% CI 0.1–0.8), higher income (> VND 4.5 vs. < 2.5 million; OR 0.2, 95% CI 0.1–0.7), and recent rehabilitation (OR 0.2, 95% CI 0.1–0.8). Among those not on ART, 16% had CD4 < 200 cells/mm³; longer injecting duration was strongly associated (OR 6.3 for > 10 vs. < 5 years, 95% CI 1.5–27.3).
Conclusions
Suboptimal HIV status awareness, ART uptake, and advanced immunosuppression among untreated PWID highlight the need for strengthened case finding and earlier engagement. Linking treatment, social support, and HIV services in closed settings could improve outcomes.
Supplementary Information
The online version contains supplementary material available at https://doi.org/10.1186/s12879-026-13180-2.
Keywords: People who inject drugs, Vietnam, HIV, Integrated behavioral and biologic survey, Antiretroviral therapy, CD4, 95:95:95
Background
People who inject drugs (PWID) have been a population that substantially contributes to the HIV epidemic in Vietnam. While the national HIV prevalence was around 0.4% in the last decade, prevalence among people who inject drugs (PWID) was approximately 10% in 2013 and 10% in 2023. It was estimated that about one third in 2013 and 10% in 2024 of new HIV infections in Vietnam were attributable to injecting drug uses. It was estimated that number of PWID was about 123,000 in 2024 [1–3].
PWID with HIV in Asia also tend to initiate antiretroviral therapy (ART) at an advanced stage of disease [4] which leads to a poor short-term prognosis even with appropriate care. Provincial estimates indicate that the proportion of PWID who have received an HIV test in the past 12 months was low – generally under 40% [2, 5]. This has important public health implications as behaviors leading to HIV transmission are common among PWID and are unlikely to be modified in those who do not know their HIV-positive status.
Understanding current levels of HIV care engagement among PWID living with HIV is essential for achieving the UNAIDS 95-95-95 targets. This study documented the prevalence of ART use and the factors associated with using ART among PWID living with HIV in two cities in Viet Nam. Additionally, we described the prevalence of low CD4 cell counts among those not using ART, who remain at high risk of morbidity, mortality, and ongoing HIV transmission, and its associated factors. While the data are historical, the findings provide valuable insights into barriers to HIV treatment access, informing ongoing and future interventions tailored to meet the need of this population in Vietnam.
Methods
Survey
The 2013 Integrated Behavioral and Biologic Survey (IBBS) was conducted among PWID in 8 provinces (Dien Bien, Yen Bai, Quang Ninh, Hanoi, Nghe An, Ho Chi Minh City, Can Tho, and An Giang) in Vietnam. Our study specifically focused on a subgroup of participants who reported being PWID living with HIV and the analysis was limited to data from Ho Chi Minh City and Can Tho, the only two provinces with sufficient resources to conduct HIV viral load (VL) and CD4 cell count testing. Two sampling strategies were used in IBBS 2013: time-location sampling (TLS) and respondent-driven samplings (RDS). For these two southern provinces, we utilized respondent-driven sampling (RDS) to enroll a representative, cross-sectional sample of the local PWID populations. RDS is designed to approximate probability sampling in hard-to-reach or marginalized populations and has been described previously [6]. It uses a limited number of well-networked and representative recruits to refer their known peers who in turn refer additional waves of known peers.
Since injecting drug use in Vietnam occurs almost exclusively among men, only male-PWID aged ≥ 18 years were recruited. Injecting drug use was defined as self-reported injection of illicit drugs at least once in the last month. Behavioral data and blood sample collection occurred at study centers within government health facilities. Trained interviewers conducted face-to-face interviews using structured questionnaires, which covered sexual and drug use behaviors, as well as exposure to HIV prevention and treatment services. Interviewers entered and saved participant responses into computerized, handheld devices (tablets) from which data were downloaded and used to compile the final dataset. An English translation of the questionnaire is provided as a supplementary file (Additional file 1). Blood samples were collected following HIV pre-test counselling. Each participant was given an appointment card to receive their HIV test results two weeks after the interview.
Laboratory
Plasma was tested for HIV antibody by enzyme-linked immunosorbent assay (Genscreen Ultra HIV Ag/Ab; Biorad, USA) and then confirmed by a second enzyme-linked immunosorbent assay (Murex HIV Ag/Ab Combination; DiaSorin, UK) and a rapid test (Determine HIV-1/2; Alere, Japan). Discordant results were assessed by re-testing samples with the screening test and secondary enzyme-linked immunosorbent assay. Remaining blood was stored at -70 °C. CD4 and VL testing was only conducted on stored blood samples from HIV-positive participants who consented to unspecified future blood analysis. During 2016–2017, stored samples were tested for HIV VL (COBAS AmpliPrep/COBAS TaqMan HIV-1 v2.0, Roche Molecular Diagnostics, USA) and CD4 cell counts (Vacutainer CD4 Stabilization Blood Collection System and FACSCount, BD Biosciences, USA). All laboratory testing and CD4 counting were carried out at the Provincial AIDS Center (PAC). Then the National Reference Laboratory at the National Institute of Hygiene and Epidemiology (NIHE) verified HIV testing performed at PAC by testing 5% of the HIV negative samples and 10% of the HIV positive samples using the testing protocol approved by Ministry of Health (MOH). All VL testing was tested at NIHE.
Ethics
All participants provided written informed consent, including consent for storage of specimens and future unspecified laboratory analyses. Participants were compensated with 100,000 Vietnam dong (approximately US $ 5.00) for their time and travel expenses. A small monetary compensation of 50,000 Vietnam dong (approximately US$2.5) was also provided to participants for each additional participant they recruited. The study was reviewed and approved by the institutional review boards of the National Institute of Hygiene and Epidemiology, Vietnam; Family Health International, Vietnam; and the U.S. Centers for Disease Control and Prevention (CDC), USA1, and CDC investigators did not interact with human subjects or access identifiable data or specimens for research purposes. The study was conducted in accordance with the ethical principles of the Declaration of Helsinki.
Data analysis
Behavioral and laboratory data were analyzed both by province and overall. The prevalence of HIV status awareness and ART use was calculated based on participants’ self-reported information. However, potential inaccuracies in self-reported HIV status due to social desirability bias may have influenced the results; for example, some participants might not disclose their HIV-positive status or unknown status even if they were on ART. To address this issue, participants with an undetectable viral load (< 20 copies/ml) were assumed to be aware of their HIV-positive status and using ART, regardless of their responses. Low CD4 cell count was defined as < 200 cells/mm3, however, we also evaluated CD4 cell count < 350 cells/mm3 – the threshold for ART initiation in 2013 as an alternative definition. RDS probability weights were calculated using RDS-Analyst software [7]. All weighted mean and weighted prevalence calculations, as well as our weighted logistic regression analyses, were conducted using the svy command set in STATA. Analyses accounted for clustering among participants enrolled by a common recruiter.
Logistic regression was used to explore factors associated with ART use among all study participants, as well as with low CD4 cell count among participants who were not using ART. All factors analyzed were considered for inclusion in our multivariate models and retained if one or more categories exhibited an adjusted p-value < 0.05. Province was considered an important variable for inclusion in all models and was retained regardless of its statistical significance due to potential regional heterogeneity in HIV epidemiology, health service availability, harm reduction coverage, and ART program implementation. These contextual differences could confound associations between individual-level factors and ART use or CD4 status.
Results
A total of 287 male-PWID living with HIV (203 from Ho Chi Minh City and 84 from Can Tho) were included, and all had HIV VL and CD4 cell count results. The mean age was 33.8 years (see Table 1).
Table 1.
Participant characteristics at the time of recruitment, among people who inject drugs with HIV in two southern provinces of Vietnam (N = 287)
| Characteristic | Ho Chi Minh City (N = 203) |
Can Tho (N = 84) |
Overall (N = 287) |
|
|---|---|---|---|---|
| Age (years) | Weighted mean (95%CI) | 33.9 (32.7–35.0) | 31.5 (30.3–32.8) | 33.8 (32.7–34.9) |
| Ethnicity | Kinh | 92.8% (85.4–96.6) | 96.0% (85.3–99.0) | 92.9% (85.9–96.6) |
| Non-Kinh | 0.6% (0.1–3.9) | 4.0% (1.0-14.7) | 0.7% (0.1–3.2) | |
| Unknown | 6.7% (3.0-14.1) | 0.0%^ | 6.4% (2.9–13.6) | |
| Living arrangement | Alone | 8.4% (4.8–14.1) | 2.0% (0.7–5.9) | 8.1% (4.7–13.6) |
| With wife/girlfriend | 16.0% (10.7–23.3) | 25.9% (15.4–40.2) | 16.4% (11.2–23.4) | |
| With relatives | 74.2% (65.9–81.1) | 72.0% (58.1–82.7) | 74.2% (66.2–80.8) | |
| Unknown | 1.4% (0.5-4.0) | 0.0%^ | 1.3% (0.5–3.8) | |
| Education level | None/primary school | 27.2% (20.5–35.2) | 47.7% (32.4–63.4) | 28.0% (21.5–35.6) |
| Secondary school | 56.6% (48.3–64.5) | 35.9% (24.3–49.4) | 55.7% (47.8–63.4) | |
| High school/university | 16.2% (10.9–23.4) | 16.4% (7.4–32.4) | 16.2% (11.0-23.1) | |
| Employment | Employed | 59.0% (50.2–67.2) | 73.1% (58.0-84.2) | 59.5% (51.1–67.4) |
| Unemployed | 36.0% (28.2–44.6) | 26.9% (15.8–42.0) | 35.6% (28.1–43.9) | |
| Unknown | 5.1% (2.2–11.4) | 0.0%^ | 4.9% (2.1–10.9) | |
| Individual monthly income (VND) | < 2.5 million | 12.7% (8.1–19.2) | 10.8% (5.9–18.7) | 12.6% (8.2–18.8) |
| 2.5–4.5 million | 38.3% (30.3–47.0) | 56.6% (41.6–70.5) | 39.0% (31.3–47.3) | |
| > 4.5 million | 37.6% (29.6–46.3) | 19.4% (10.1–34.2) | 36.9% (29.2–45.2) | |
| Unknown | 11.5% (6.2–20.2) | 13.2% (6.6–24.7) | 11.5% (6.4–19.8) | |
| Self-reported HIV status prior to survey* | Positive | 55.4% (47.1–63.4) | 52.1% (35.7–68.1) | 55.2% (47.3–62.9) |
| Negative | 6.8% (3.4–13.2) | 14.4% (6.7–28.2) | 7.1% (3.7–13.1) | |
| Do not know | 37.8% (30.0-46.3) | 33.5% (22.1–47.2) | 37.6% (30.2–45.8) | |
| Duration of injecting drug use (years) | < 5 | 20.3% (14.2–28.2) | 33.5% (21.2–48.7) | 20.8% (14.9–28.3) |
| 5–10 | 19.3% (13.8–26.4) | 29.6% (18.3–44.1) | 19.7% (14.3–26.5) | |
| > 10 | 56.1% (47.9–64.1) | 36.9% (23.4–52.8) | 55.4% (47.4–63.0) | |
| Unknown | 4.3% (1.4–12.4) | 0.0%^ | 4.1% (1.3–11.9) | |
| Usual frequency of injecting drug use (per day) | Once | 13.5% (8.3–21.3) | 24.2% (14.1–38.1) | 13.9% (8.9–21.3) |
| Twice | 59.7% (51.4–67.5) | 59.0% (43.8–72.5) | 59.7% (51.7–67.2) | |
| > Twice | 26.7% (20.0-34.8) | 16.9% (7.9–32.6) | 26.4% (19.9–34.0) | |
| Current use of methadone maintenance therapy | Using | 6.8% (3.4–13.0) | 3.8% (1.2–10.9) | 6.7% (3.4–12.6) |
| Not using | 93.2% (87.0-96.6) | 96.2% (89.1–98.8) | 93.3% (87.4–96.6) | |
| Ever attended drug rehabilitation1 – ever | Yes | 64.3% (55.9–72.0) | 58.9% (43.1–73.1) | 64.1% (56.0-71.5) |
| No | 29.0% (22.1–37.0) | 41.1% (26.9–56.9) | 29.5% (22.8–37.2) | |
| Unknown | 6.7% (3.0-14.1) | 0.0%^ | 6.4% (2.9–13.6) | |
| Attended drug rehabilitation in past 12 months | Yes | 7.1% (3.9–12.7) | 10.6% (4.9–21.4) | 7.2% (4.1–12.5) |
| No | 84.6% (76.8–90.1) | 87.7% (76.2–94.1) | 84.7% (77.3–90.0) | |
| Unknown | 8.3% (4.2–15.7) | 1.7% (0.2–11.6) | 8.0% (4.1–15.1) | |
In Vietnam, in the past drug users were mandatorily sent to rehabilitation centers for drug treatment as well as for job training. At present, if drug treatment in the community fails, then drug users are sent to rehabilitation centers for mandatory treatment
All values are presented as weighted percentages (95% confidence interval) unless otherwise indicated. *Participants with undetectable viral load were assumed to be aware of their HIV-positive status regardless of their survey responses; ^Confidence intervals were not calculated for exact 0% and 100% values; CI, confidence interval; VND, Vietnamese Dong
We found that just over half of participants (55.2%) were aware of their HIV-positive status. Importantly, 48.8% of participants, or 88.4% of those who were aware of their HIV positivity, were using ART. Furthermore, 81.6% of those on ART had undetectable VL. (Data not shown).
Older age (odds ratio [OR] 4.9 for participants > 40 years versus those < 30 years, 95% confidence interval [95% CI] 1.2–20.5) and current use of opioid substitution therapy (OST) (OR 12.7 versus non-use, 95% CI 1.1-141.7) were associated with a higher prevalence of ART use (see Table 2). Living alone (OR 0.1 versus living with relatives, 95% CI 0.0-0.5), living with one’s wife or girlfriend (OR 0.3 versus living with relatives, 95% CI 0.1–0.8), having a higher individual income (OR 0.2 for incomes > VND 4.5 million versus those < VND 2.5 million, 95% CI 0.1–0.7), and attending drug rehabilitation2 in the past 12 months (OR 0.2 versus not attending, 95% CI 0.1–0.8) were associated with a lower prevalence of ART use. The adjusted prevalence of ART use did not differ by province.
Table 2.
Factors associated with antiretroviral therapy use among people who inject drugs with HIV in southern Vietnam (N = 287)
| Characteristic | Raw overall N | Weighted % using ART | Univariate | Multivariate | ||
|---|---|---|---|---|---|---|
| OR (95%CI) | p | aOR (95%CI) | p | |||
| Age (years) | ||||||
| < 30 | 92 | 33.7% | 1.0 | 1.0 | ||
| 30–40 | 156 | 54.3% | 2.3 (1.1–5.1) | 0.04 | 2.5 (1.1–5.8) | 0.04 |
| > 40 | 39 | 60.3% | 3.0 (0.9–9.7) | 0.07 | 4.9 (1.2–20.5) | 0.03 |
| Living arrangement | ||||||
| Alone | 21 | 21.2% | 0.2 (0.1–0.9) | 0.04 | 0.1 (0.0-0.5) | < 0.01 |
| With wife/girlfriend | 59 | 46.9% | 0.8 (0.3–1.9) | 0.58 | 0.3 (0.1–0.8) | 0.02 |
| With relatives | 203 | 53.1% | 1.0 | 1.0 | ||
| Unknown | 4 | 0.0% | - | - | ||
| Education level | ||||||
| None/primary school | 86 | 45.7% | 1.0 | |||
| Secondary school | 152 | 48.5% | 1.1 (0.5–2.4) | 0.77 | ||
| High school/university | 49 | 54.8% | 1.4 (0.5–3.9) | 0.47 | ||
| Employment | ||||||
| Employed | 189 | 44.0% | 1.0 | |||
| Unemployed | 87 | 58.1% | 1.8 (0.8–3.7) | 0.14 | ||
| Unknown | 11 | 39.0% | - | |||
| Individual monthly income (VND) | ||||||
| < 2.5 million | 34 | 62.8% | 1.0 | 1.0 | ||
| 2.5–4.5 million | 115 | 55.6% | 0.7 (0.3–2.2) | 0.59 | 0.6 (0.2-2.0) | 0.37 |
| > 4.5 million | 107 | 31.9% | 0.3 (0.1–0.8) | 0.02 | 0.2 (0.1–0.7) | 0.01 |
| Unknown | 31 | 64.3% | - | - | ||
| Duration of injecting drug use (years) | ||||||
| < 5 | 60 | 37.3% | 1.0 | |||
| 5–10 | 63 | 42.8% | 1.3 (0.4–3.6) | 0.67 | ||
| > 10 | 160 | 54.9% | 2.0 (0.8-5.0) | 0.12 | ||
| Unknown | 4 | 52.6% | - | |||
| Usual frequency of injecting drug use (per day) | ||||||
| Once | 41 | 57.1% | 1.0 | |||
| Twice | 168 | 46.1% | 0.6 (0.2–1.8) | 0.40 | ||
| > Twice | 78 | 50.5% | 0.8 (0.3–2.3) | 0.64 | ||
| Current use of methadone | ||||||
| Using methadone | 19 | 91.1% | 12.2 (1.7–89.0) | 0.01 | 12.7 (1.1-141.7) | 0.04 |
| Not using methadone | 268 | 45.7% | 1.0 | 1.0 | ||
| Ever attended drug rehabilitation 1 | ||||||
| Yes | 193 | 48.2% | 1.0 (0.5-2.0) | 0.94 | ||
| No | 80 | 48.9% | 1.0 | |||
| Unknown | 14 | 53.8% | - | |||
| Attended drug rehabilitation in past 12 months | ||||||
| Yes | 25 | 20.8% | 0.3 (0.1-1.0) | 0.06 | 0.2 (0.1–0.8) | 0.02 |
| No | 244 | 49.8% | 1.0 | 1.0 | ||
| Unknown | 18 | 63.1% | - | - | ||
| Province | ||||||
| Ho Chi Minh City | 203 | 48.9% | 1.0 | 1.0 | ||
| Can Tho | 84 | 46.6% | 0.9 (0.4-2.0) | 0.81 | 1.1 (0.4–2.7) | 0.85 |
1 In Vietnam, in the past drug users were mandatorily sent to rehabilitation centers for drug treatment as well as for job training. At present, if drug treatment in the community fails, then drug users are sent to rehabilitation centers for mandatory treatment
Participants with missing data were included in all models but odds ratios for unknown categories are not presented. OR, odds ratio; aOR, adjusted odds ratio; CI, confidence interval; VND, Vietnamese dong
Figure 1 also shows that 27.5% of PWID with HIV were not using ART with a CD4 cell count < 350 cells/mm3, and 15.7% were not using ART with a CD4 cell count < 200 cells/mm3. Among those not using ART, longer duration of injecting drug use (OR 6.3 for > 10 years versus < 5 years of injecting drug use, 95% CI 1.5–27.3) and province (OR 0.3 for Can Tho versus Ho Chi Minh City, 95% CI 0.1–0.7) were factors significantly associated with a CD4 cell count < 200 cells/mm3 (Table 3). Similar but attenuated results were seen with a CD4 cell count threshold of < 350 cells/mm3, with an OR of 2.4 for > 10 years of injecting drug use versus < 5 years (95% CI 0.8-7.0) and OR of 0.7 for Can Tho versus Ho Chi Minh City (95% CI 0.3–1.6).
Fig. 1.
Weighted prevalence of antiretroviral therapy non-use and antiretroviral therapy non-use with low CD4 cell count among people who inject drugs with HIV in two southern provinces of Vietnam
Table 3.
Factors associated with CD4 cell count < 200 cells/mm3 in individuals not using antiretroviral therapy among people who inject drugs living with HIV in two southern provinces of Vietnam (N = 153)
| Characteristic | Raw overall N | Weighted % with CD4 < 200 | Univariate | Multivariate | ||
|---|---|---|---|---|---|---|
| OR (95%CI) | p | aOR (95%CI) | p | |||
| Age (years) | ||||||
| < 30 | 61 | 29.5% | 1.0 | |||
| 30–40 | 73 | 30.0% | 1.0 (0.4–2.9) | 0.97 | ||
| > 40 | 19 | 37.2% | 1.4 (0.3–5.7) | 0.63 | ||
| Living arrangement | ||||||
| Alone | 16 | 33.9% | 1.3 (0.3–5.1) | 0.70 | ||
| With wife/girlfriend | 30 | 37.3% | 1.5 (0.4–6.4) | 0.58 | ||
| With relatives | 103 | 28.2% | 1.0 | |||
| Unknown | 4 | 34.9% | - | |||
| Education level | ||||||
| None/primary school | 50 | 38.6% | 1.0 | |||
| Secondary school | 81 | 29.4% | 0.7 (0.2-2.0) | 0.46 | ||
| High school/university | 22 | 18.9% | 0.4 (0.1–1.7) | 0.21 | ||
| Employment | ||||||
| Employed | 112 | 26.9% | 1.0 | |||
| Unemployed | 38 | 34.1% | 1.4 (0.5-4.0) | 0.52 | ||
| Unknown | 3 | 54.4% | - | |||
| Individual monthly income (VND) | ||||||
| < 2.5 million | 14 | 19.1% | 1.0 | |||
| 2.5–4.5 million | 59 | 44.7% | 3.4 (0.4–29.9) | 0.27 | ||
| > 4.5 million | 67 | 21.6% | 1.2 (0.2–8.8) | 0.88 | ||
| Unknown | 13 | 39.8% | - | |||
| Duration of injecting drug use (years) | ||||||
| < 5 | 39 | 8.3% | 1.0 | 1.0 | ||
| 5–10 | 39 | 30.5% | 4.8 (1.0-22.7) | 0.05 | 5.0 (1.0-23.6) | 0.04 |
| > 10 | 73 | 37.0% | 6.5 (1.5–27.6) | 0.01 | 6.3 (1.5–27.3) | 0.01 |
| Unknown | 2 | 100.0% | - | - | ||
| Frequency of injecting drug use (per day) | ||||||
| Once | 24 | 51.2% | 1.0 | |||
| Twice | 92 | 26.8% | 0.3 (0.1–1.3) | 0.11 | ||
| > Twice | 37 | 30.7% | 0.4 (0.1-2.0) | 0.28 | ||
| Ever attended drug rehabilitation | ||||||
| Yes | 101 | 31.2% | 1.4 (0.5–3.9) | 0.54 | ||
| No | 49 | 24.7% | 1.0 | |||
| Unknown | 3 | 54.4% | - | |||
| Attended drug rehabilitation in past 12 months | ||||||
| Yes | 17 | 25.2% | 0.8 (0.2–3.9) | 0.78 | ||
| No | 133 | 29.7% | 1.0 | |||
| Unknown | 3 | 54.4% | - | |||
| Province | ||||||
| Ho Chi Minh City | 103 | 31.5% | 1.0 | 1.0 | ||
| Can Tho | 50 | 9.5% | 0.2 (0.1–0.6) | < 0.01 | 0.3 (0.1–0.7) | 0.01 |
Participants with missing data were included in all models but odds ratios for unknown categories are not presented. OR, odds ratio; aOR, adjusted odds ratio; CI, confidence interval; VND, Vietnamese dong
Discussion
This study provides important insights into ART use and immunologic status among PWID living with HIV in two urban centers of Vietnam. Just over half of participants were aware of their HIV-positive status, and while most of those engaged in care achieved viral suppression, a substantial proportion remained undiagnosed or untreated. These findings underscore that HIV case finding remains a critical gap in reaching the UNAIDS 95–95–95 targets.
Our finding that more than half of participants were aware of their HIV-positive status represents a modest increase compared with earlier IBBS estimates [8]. This increase was due to the re-classification of those with an undetectable viral load who reported a negative or unknown status. Nevertheless, the fact that approximately half of PWID living with HIV in Ho Chi Minh City and Can Tho did not know they are HIV-positive remains a concern. This is consistent with the 2014 UNAIDS report which estimated that only 48% of people living with HIV know their status worldwide [9]. Major of those who were aware of their HIV positivity, were liked to ART. Importantly, most of those on ART had undetectable VL. These findings indicate that PWID with HIV in Vietnam are likely linked to ART if they are aware of HIV status and do well once they are engaged in treatment.
An association between older age and higher prevalence of ART use has been demonstrated elsewhere [10] and may be indicative of those with a longer duration of HIV infection being more likely to have sought care. We also found that being engaged in OST was highly associated with ART use. This highlights the effectiveness of the linkage between OST clinics and HIV testing sites in Vietnam, and reinforces the findings of a recent systematic review which found that OST was associated with a 54% increase in ART coverage among PWID [11]. Conversely, those with a recent history of attending a drug rehabilitation center had a low probability of ART use. Although admission to drug rehabilitation is typically associated with mental, social and financial instabilities [12] which may complicate ART use, it can be important to explore all potential opportunities for improving HIV care engagement. While significant barriers exist in these facilities, efforts to expand evidence-based approaches such as OST and integrated HIV services remain critical in ensuring effective and equitable access to HIV testing and treatment for PWID. Our data suggest that more could be done to utilize this opportunity in Ho Chi Minh City and Can Tho. PWID living alone or with their partner were less likely to be on ART than those living with relatives. This is consistent with other studies which have shown people living with HIV are more likely to use and adhere to ART when they have strong social support at home [13, 14]. Importantly, this association appears to be contingent upon the disclosure of one’s HIV status within the household or among friend and acquaintance networks [14]. Those with a high individual income also had a lower rate of ART use. This could be related to the ongoing stigma suffered by people living with HIV and PWID in Vietnam [15] and concern that using ART use will lead to one’s HIV status becoming more widely known. Well-paid PWID may feel that the benefit of ART is not worth the potential loss of income associated with being identified as HIV-positive.
In a large Asian HIV cohort, late ART initiation (defined as a CD4 cell count < 200 cells/mm3 or an AIDS diagnosis prior to starting ART) declined from 82.4% in 2007 to 36.3% after 2011 [4]. While we report a lower proportion of PWID with HIV not using ART with a CD4 count < 200 cells/mm3, our numerator did not include participants who had already started ART with a low CD4 count nor those with a history of AIDS. Unfortunately, we did not have data available on prior AIDS diagnoses or CD4 cell count at ART initiation.
Long-term PWID are more likely than short-term ones to have a history of illness due to advanced symptoms of HIV infection and are less likely to seek help for their drug addiction [16]. These factors could impair the ability of long-term PWID to recognize and act upon advanced symptoms of HIV infection, resulting in them seeking care only when they are severely unwell. Unfortunately, as it has now been well documented, late ART initiation leads to a substantially elevated risk of morbidity and mortality [17]. Compared with other provinces, the PWID population in Ho Chi Minh City comprises a large number of long-term users [2]. However, even after adjusting for the duration of injecting drug use, we found PWID living with HIV in Can Tho had lower adjusted odds of having a low CD4 count compared to those in Ho Chi Minh City. It is uncertain what is driving this association, but it highlights an important issue for health care providers and policy makers in Ho Chi Minh City.
The marked decline in the proportion of new HIV infections attributable to injecting drug use in Vietnam over the past decade likely reflects the substantial scale-up of evidence-based harm-reduction and treatment interventions. Expanded coverage of needle and syringe programs, OST, and antiretroviral treatment among PWID has been shown to reduce HIV incidence in this population. In parallel, improved HIV testing and earlier treatment initiation may have reduced onward transmission among PWID. At the same time, the relative contribution of injecting drug use to new HIV infections has declined as sexual transmission, particularly among men who have sex with men, has become a more prominent driver of the epidemic. Together, these shifts underscore both the success of harm-reduction programs for PWID and the need to sustain and adapt HIV prevention strategies across populations at higher risk for HIV [3, 5, 18].
The cross-sectional design precludes causal inference between identified factors and ART use or CD4 status. Associations observed should therefore be interpreted as correlational rather than causal. Our study population only comprised of PWID living in Ho Chi Minh City and Can Tho hence the results may not be generalizable to other parts of Vietnam. Much of our data on risk behaviors were collected via self-reporting, which is subject to recall and influenced by social norms. Our efforts to mitigate such influences included obtaining informed consent, intensive training for staff related to interview techniques to establish trust with the participants, and triangulating responses with multiple questions to identify discrepancies. We attempted to reduce misclassification by reclassifying participants with undetectable viral load as being aware of their HIV-positive status and on ART. We analyzed factors associated with ART use and low CD4 cell count by combining provincial data based on the assumption that associations were similar across provinces. Pooling data increased the study’s statistical power, allowing for more robust inferences that could be more readily translated into policy and practice. Although these data were collected in 2013, there has since been significant expansion of HIV testing, ART, and medication-assisted treatment services for PWID in Vietnam. Nevertheless, the risk factors identified in this analysis remain important considerations, as they continue to inform current and future interventions aimed at reducing late ART initiation and improving treatment outcomes among PWID. Despite these limitations, the study offers valuable insights into gaps in HIV diagnosis, treatment uptake, and immunologic status among PWID, and identifies subgroups that may benefit from targeted interventions to prevent late ART initiation and advanced immunosuppression.
Conclusion
Just over half of PWID were aware of their HIV-positive status, and among those, nearly nine out of ten were receiving antiretroviral therapy (ART), with most achieving undetectable viral load. ART use was associated with older age and engagement in OST, whereas certain social and structural factors including living arrangements, income, and recent attendance at drug rehabilitation facilities were associated with lower treatment uptake. Among those not on ART, a notable proportion had severely low CD4 cell counts, with longer durations of injecting drug use strongly associated to advanced immunosuppression. Although these data were collected in 2013, the findings provide important historical context and underscore persistent barriers to timely HIV diagnosis and treatment among PWID. To achieve the UNAIDS 95:95:95 goals, expanding HIV testing including case finding effort in community and closed settings, and treatment services tailored to meet the need of PWID may increase the awareness of HIV status and engagement in HIV care among this population. PWID with HIV who reside in mandatory rehabilitation centers are an accessible group who could be better linked to HIV care. These insights remain relevant for informing HIV program design aimed at promoting early ART initiation improving outcomes among PWID with HIV in Vietnam and similar settings.
Supplementary Information
Below is the link to the electronic supplementary material.
Acknowledgements
The authors thank the study participants and the provincial survey teams for their contribution to the 2013 IBBS. We also acknowledge the technical support of the Vietnam Administration of Disease Control and Prevention (formally Vietnam Administration of HIV/AIDS Control) – Ministry of Health, the National Institute of Hygiene and Epidemiology, and Family Health International, Vietnam.
Abbreviations
- AIDS
Acquired immunodeficiency syndrome
- ART
Antiretroviral therapy
- BBS
Behavioral and biologic survey
- CDC
U.S. centers for disease control and prevention
- CI
Confidence interval
- HIV
Human immunodeficiency virus
- IBBS
Integrated behavioral and biologic survey
- IDU
Injecting drug user
- MMT
Methadone maintenance therapy
- MOH
Ministry of health
- MSM
Men who have sex with men
- OR
Odds ratio
- PAC
Provincial AIDS center
- PEPFAR
U.S. president’s emergency plan for AIDS relief
- PLHIV
People living with HIV
- PWID
People who inject drugs
- RDS
Respondent-driven sampling
- STI
Sexually transmitted infection
- UNAIDS
Joint united nations programme on HIV/AIDS
- VL
Viral load
- VND
Vietnamese dong
- WHO
World Health Organization
Author contributions
D.C.T. conceived the study, led data analysis, interpretation, and manuscript drafting. D.C.B. contributed to data interpretation, manuscript development, and critical revisions. A.A.Q. provided methodological guidance and critically reviewed the manuscript for important intellectual content. H.T.T.H. and P.H.T. contributed to study design, data collection coordination, and interpretation of findings. All authors reviewed and approved the final manuscript for submission and agree to be accountable for all aspects of the work.
Funding
The research has been supported by the President’s Emergency Plan for AIDS Relief (PEPFAR) through the U.S. Centers for Disease Control and Prevention (CDC) under the terms of 5U2GGH000116.
Data availability
The dataset analyzed in this study is owned by the Vietnam Ministry of Health and the National Institute of Hygiene and Epidemiology. Data are available upon reasonable request and with permission from the Ministry of Health.
Declarations
Ethics approval and consent to participate
The study was reviewed and approved by the institutional review boards of the National Institute of Hygiene and Epidemiology, Vietnam; Family Health International, Vietnam; and the U.S. Centers for Disease Control and Prevention, USA, and CDC investigators did not interact with human subjects or access identifiable data or specimens for research purposes. The study was conducted in accordance with the ethical principles of the Declaration of Helsinki. All participants provided written informed consent, including consent for storage of specimens and future unspecified laboratory analyses.
Consent for publication
Not applicable.
Competing interests
The findings and conclusions in this paper are those of the authors and do not necessarily represent the official position of the funding agencies.
Footnotes
See 45 Code of US Federal Regulations (C.F.R.), part 46; 21 C.F.R. part 56.
In Vietnam, in the past drug users were mandatorily sent to rehabilitation centers for drug treatment as well as for job training. At present, if drug treatment in the community fails, then drug users are sent to rehabilitation centers for mandatory treatment.
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Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
References
- 1.UNAIDS. Country factsheet - Vietnam 2024 Available from: https://www.unaids.org/en/regionscountries/countries/vietnam
- 2.Ministry of Health - National Institute of Hygiene and Epidemiology. HIV/STI Integrated Biological and Behavioral Surveillance (IBBS) in Vietnam - Results from round III 2013 and trends across three rounds (2005-2009-2013) of surveys. Available from: https://www.researchgate.net/publication/305471855_HIVSTI_Integrated_Biologcial_and_Behavioral_Surveillance_IBBS_in_Vietnam_-_Results_from_Round_III_and_Trends_Across_Three_Rounds_2005_-_2009_-_2013_of_Surveys
- 3.MOH. AIDS epidemic model analysis for mid-term review of the national strategy to end AIDS by 2030. Hanoi: Ministry of Health – Vietnam Administration of Disease Control; 2025.
- 4.Kiertiburanakul S, Boettiger D, Lee MP, Omar SF, Tanuma J, Ng OT, et al. Trends of CD4 cell count levels at the initiation of antiretroviral therapy over time and factors associated with late initiation of antiretroviral therapy among Asian HIV-positive patients. J Int AIDS Soc. 2014;17:18804. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 5.Vietnam Administration for HIV/AIDS Control. Prevalence of HIV, syphilis, and related risk behaviors among men who have sex with men, male people who inject drugs, female sex workers in Vietnam: findings from HIV Sentinel Surveillance Plus (HSS+). Hanoi: Vietnam Ministry of Health; 2025. p. 2012–22.
- 6.Tran HV, Le LV, Johnston LG, Nadol P, Van Do A, Tran HT, et al. Sampling males who inject drugs in Haiphong, Vietnam: comparison of time-location and respondent-driven sampling methods. J Urban Health. 2015;92(4):744–57. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 7.Handcock M, Fellows I, Giles K. Deducer RDS Analyst: graphical user interface to the RDS package for respondent-driven sampling. Version 0.1. 2012. Available from: http://hpmrg.org
- 8.Duong CT, Abdul-Quader A, Nguyen TA, editors. Knowledge of HIV status, enrolment in care, and CD4 count among HIV+ PWID in Vietnam. In: Australian HIV/AIDS Conference; 6–8 November 2016; Adelaide, Australia.
- 9.UNAIDS. The Gap Report 2014. Available from: http://www.unaids.org/sites/default/files/media_asset/UNAIDS_Gap_report_en.pdf
- 10.Hoots BE, Finlayson TJ, Broz D, Paz-Bailey G, Group NS. Antiretroviral therapy use among HIV-infected people who inject drugs-20 cities, United States, 2009–2015. J Acquir Immune Defic Syndr. 2017;75(Suppl 3):S392–6. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 11.Low AJ, Mburu G, Welton NJ, May MT, Davies CF, French C, et al. Impact of opioid substitution therapy on antiretroviral therapy outcomes: a systematic review and meta-analysis. Clin Infect Dis. 2016;63(8):1094–104. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 12.Opsal A, Kristensen O, Larsen TK, Syversen G, Rudshaug EB, Gerdner A, et al. Factors associated with involuntary admissions among patients with substance use disorders and comorbidity: a cross-sectional study. BMC Health Serv Res. 2013;13:57. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 13.Gibbie T, Hay M, Hutchison CW, Mijch A. Depression, social support and adherence to highly active antiretroviral therapy in people living with HIV/AIDS. Sex Health. 2007;4(4):227–32. [DOI] [PubMed] [Google Scholar]
- 14.Waddell EN, Messeri PA. Social support, disclosure, and use of antiretroviral therapy. AIDS Behav. 2006;10(3):263–72. [DOI] [PubMed] [Google Scholar]
- 15.Viet Nam Network of People Living with HIV (VNP+). Stigma Index Report 2014 2014. Available from: https://www.aidsdatahub.org/sites/default/files/resource/plhiv-stigma-index-2014-viet-nam.pdf
- 16.Hacker MA, Friedman SR, Telles PR, Teixeira SL, Bongertz V, Morgado MG, et al. The role of long-term and new injectors in a declining HIV/AIDS epidemic in Rio de Janeiro, Brazil. Subst Use Misuse. 2005;40(1):99–123. [DOI] [PubMed] [Google Scholar]
- 17.Group ISS, Lundgren JD, Babiker AG, Gordin F, Emery S, Grund B, et al. Initiation of antiretroviral therapy in early asymptomatic HIV infection. N Engl J Med. 2015;373(9):795–807. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 18.UNAIDS. Strengthening Viet Nam’s national HIV response: key findings and policy recommendations. 2025. Contract No.: 15 Sep 2025.
Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Supplementary Materials
Data Availability Statement
The dataset analyzed in this study is owned by the Vietnam Ministry of Health and the National Institute of Hygiene and Epidemiology. Data are available upon reasonable request and with permission from the Ministry of Health.