Figures
Abstract
Objective
To report the viral load and CD4 count in HIV-infected, antiretroviral naïve, first -time HIV-testers, not immediately eligible for treatment initiation by current South Africa treatment guidelines.
Design
This was a cross-sectional study in a high-volume, free-of-charge HIV testing centre in Soweto, South Africa.
Methods
We enrolled first time HIV testers and collected demographic and risk-behaviour data and measured CD4 count and viral load.
Results
Between March and October 2011, a total of 4793 adults attended VCT and 1062 (22%) tested positive. Of the 1062, 799 (75%) were ART naïve and 348/799 (44%) were first-time HIV testers. Of this group of 348, 225 (65%) were female. Overall their median age, CD4 count and viral load was 34 years (IQR: 28-41), 364 (IQR: 238-542) cells/mm3 and 13,000 (IQR: 2050-98171) copies/ml, respectively. Female first time HIV testers had higher CD4 counts (419 IQR: 262-582 vs. 303 IQR: 199-418 cells/mm3) and lower viral loads (9,100 vs. 34,000 copies/ml) compared to males. Of 183 participants with CD4 count >350 cells/mm3, 62 (34%) had viral loads > 10,000 copies/ml.
Citation: Govender S, Otwombe K, Essien T, Panchia R, de Bruyn G, Mohapi L, et al. (2014) CD4 Counts and Viral Loads of Newly Diagnosed HIV-Infected Individuals: Implications for Treatment as Prevention. PLoS ONE 9(3): e90754. https://doi.org/10.1371/journal.pone.0090754
Editor: William A. Paxton, Institute of Infection and Global Health, United Kingdom
Received: November 14, 2013; Accepted: February 3, 2014; Published: March 4, 2014
Copyright: © 2014 Govender et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Funding: This study was funded by Canadian African Prevention Trials Network (CAPT) and Presidents Emergency Plan For AIDS Relief (PEPFAR). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. KO has received research training from the Fogarty International Center (TW007373/0).
Competing interests: The authors have declared that no competing interests exist.
Introduction
Anti-retroviral therapy (ART) initiation has been shown to dramatically reduce HIV transmission in discordant heterosexual couples prompting revisions to treatment eligibility criteria. [1]–[3] Responding to this, new guidelines recommend starting ART either at HIV diagnosis, or at CD4 counts of ≤500 cells/mm3. [4], [5] Current South African (SA) treatment guidelines for ART include recommendations for treatment initiation at a CD4 threshold of ≤ 350 cells/mm3 in non-pregnant, well adolescents and adults.[4], [5].
ART initiation is traditionally based on CD4 counts. In conjunction with viral loads, they allow prognostication. [6] Moreover, viral loads provide a measure of infectivity; individuals with low or suppressed viral loads have markedly lower transmission rates. [7], [8]
This study reports the distribution of CD4 counts and viral loads in ART-naïve, first-time HIV testers and relates CD4 counts to current South African ART initiation thresholds, and the proportion of participants not qualifying for immediate initiation of ART by the CD4 criterion but who have high viral loads and high potential of onward HIV transmission.
Materials and Methods
We analysed data collected at the ZAZI clinic which is a free-of-charge, voluntary counselling and testing (VCT) facility on the campus of the Chris Hani Baragwanath Academic Hospital in Soweto, South Africa. The clinic is connected by a pedestrian bridge to a busy taxi rank. ZAZI tested 15,824 walk-in patients from October 2010 to September 2011. Participants included in this analysis had to be ART-naïve, self-report being HIV tested for the first time, and have no clinical evidence of an AIDS defining condition (WHO Stage 1 or 2 diseases).
Study design
This was a cross-sectional study. All consenting participants were sequentially enrolled, had demographic and behavioural profiles captured and were symptom-screened for tuberculosis and other opportunistic infections. Behavioural profile questions related to number of sexual partners, condom and alcohol usage in the month prior to testing were collected using face-to-face interviews in routine VCT counselling procedure by counsellors. Blood draws for CD4 count and viral load were taken at the time of HIV diagnosis. Those eligible for ART (with CD4 ≤ 350 cells/mm3 as per South African HIV treatment guidelines [4]) were referred to treatment facilities whereas the remaining were followed up at ZAZI at six month intervals. Study data collection was conducted between March 2011 and October 2011.
HIV testing was by double-rapid test algorithm. Those testing negative on SD Bioline HIV 1/2 3.0 rapid test (Standard Diagnostics Inc, Gyeonggi-do, Republic of Korea) were not retested. Positive rapid tests were confirmed with a second rapid test (First Response, Premier Medical Corporation Limited, Daman, India). Discordant rapid test results were resolved with a laboratory HIV ELISA test. Blood was drawn and stored in tubes in room temperature where laboratory staff would collect them daily at scheduled times. No blood stayed overnight in the clinic. HIV-infected clients received CD4 and viral load results within two days of testing and those eligible for treatment and care were referred to local clinics.
Laboratory testing
Viral Load testing was conducted using the Nuclisens Nucleic Acid Sequence Based Amplification (NASBA, bioMerieux, Inc. Durham, NC) test platform for most tests (the detection limit for HIV viral load was < 400 copies/ml) and the Real Time HIV-1 Amplification Polymerase Chain reaction (PCR) (ABBOTT Molecular, Inc, Des Plaines, IL) platform in a few instances. CD4 cells were enumerated using the dual platform method. [9].
Written consent was obtained from each participant for their information to be stored in the clinic database and used for research purposes. The study was approved by the University of the Witwatersrand Human Research Ethics Committee.
Statistical analysis
Median and interquartile ranges were determined for age, CD4 count and viral loads. Continuous measures were compared using the Kruskall-Wallis non-parametric test. CD4 count was categorised dichotomously based on the South African treatment guidelines while viral loads were classified using >10,000 copies/ml as probable high infectivity, based on prior HIV transmission related studies.[8], [10], [11] Overall frequencies and their percentages were determined for categorical variables and by gender. The viral loads between males and females were compared while adjusting for CD4 count and age using analysis of covariance. Behavioural variables stratified by CD4 count and viral load categories were compared using the chi-square test. We determined the correlation between log10 viral load versus CD4 count, and included the least squares line by gender on a scattergram. All hypothesis testing used two-sided tests at 5% significance level using SAS 9.3 (SAS Institute, Cary, NC) statistical software.
Results
A total of 4,793 adults attended VCT between March and October 2011, of whom 1062 (22%) tested HIV-positive (Figure 1). Of the 1062 HIV-infected adults, 799 (75%) were ART naïve, of whom 348 (44%) were first time testers. The leading reasons for exclusion of ineligible participants were: being previously tested (n = 451) and not being ART naïve (n = 263). The median age of all ineligible participants was 35 years (IQR: 30-40), their median CD4 count and viral load was 304 cells/mm3 (IQR: 188-446) and 26,000 copies/ml (IQR: 4,100-140,000), respectively. Ineligible participants were excluded from further analyses.
The median age of the ART-naïve, first time testers was 34 years (IQR: 28-41). Males presented at older age than females (36 vs. 33; p = 0.0086). The overall median CD4 count was 364 cells/mm3 (IQR: 238.0-541.5); median CD4 count in females was higher than males (419 cells/mm3 vs. 303 cells/mm3; p = 0.0001). A total of 183 (53%) participants had CD4 count >350 cells/mm3; the proportion of females with CD4 above 350 cells/mm3 was higher than males (60% vs. 40%, p = 0.0004; Table 1).
Overall the median viral load for ART-naïve, first time testers was 13,000 copies/ml (IQR: 2050-98,171). Females had a markedly lower median viral load compared to males (9,100 vs. 34,000 copies/ml, p = 0.0005). Overall, 187 (54%) participants had viral loads > 10,000 copies/ml. The proportion of males with viral loads >10,000 copies/ml was significantly higher than females (64% vs. 48%; p = 0.0037). Of the 183 participants with CD4 count >350 cells/mm3, 62 (34%) had a viral load > 10,000 copies/ml.
The proportion of males and females with CD4 count >350 cells/mm3 and with viral loads >10,000 copies/ml were similar (males 19/49 [39%] vs. females 43/134 [32%]; p = 0.3975). The distribution of CD4 counts within the two viral load strata (> 10,000 and ≤ 10,000 copies/ml) was not statistically different (Table 2). After adjusting for CD4 count and age, females had a significantly lower HIV viral load compared to males (p = 0.0067).
Of those with CD4 > 350 cells/mm3 and VL > 10,000 copies/ml, males were more likely to report alcohol use (15/19 (79%) vs. 13/39 (33%), p = 0.0011). Those with a CD4 ≤ 350 cells/mm3 were more likely to have more than one partner than participants with CD4 > 350 (p = 0.0414). Condom use, alcohol use and reason for HIV testing were similar between the two CD4 strata of ≤ 350 and > 350 cells/mm3 (Table 3). There was a negative moderate Pearson correlation of -0.504 between log10 viral load and CD4 count (Figure 2) for all participants.
Discussion
We report CD4 counts and viral loads in adult first-time HIV testers who were well, ART naïve, and diagnosed with HIV at an easily accessible, high volume, free-of-charge VCT centre. A large proportion of HIV infected adults not qualifying for immediate ART at the CD4 count threshold of 350 cells/mm3 had high viral loads. Of the ART-naïve first time testers whose CD4 count was above the CD4 threshold for ART initiation as per South African guidelines, 34% had a VL > 10,000 copies/ml suggesting that CD4 count at the time of HIV diagnosis is a poor proxy for HIV transmission risk. Consideration should be given to replacing CD4 count threshold with viral load threshold for ART initiation when planning treatment as prevention (TasP) interventions.
Our results show that most asymptomatic adults requesting HIV testing for the first time had low CD4 counts (median CD4 count 364 cells/mm3) and/or high viral loads (median viral load 13,000 copies/ml). Indeed, almost half of all the asymptomatic first-time testers in this study qualified for immediate initiation of ART according to current South Africa guidelines; most were men. This result underlies the importance of reducing the time to first testing in men. Other studies have noted gender differences in viral loads and CD4 at various stages of the disease, where females develop AIDS at higher CD4 counts and lower viral loads.[12]–[15] The higher median viral load of males increases the rate of disease progression, CD4 decline and relative infectivity (when in a discordant relationship).[1], [16].
Limitations to this study include social desirability bias that may have resulted in misclassification of participants as first-time testers and being ART-naïve. Moreover, the cross- sectional nature of the study does not reflect the dynamic nature of CD4 counts.
Although not an original part of this research, a surprising finding was the high number of HIV testers who were taking ART. They were identified by their low viral loads, and on further questioning reported receiving ART. We speculate, in the absence of supporting data, that there is a sizable group of patients on ART who either want a CD4 count without having to undergo a formal ART clinic visit, or want to confirm their HIV-infection after being told in lay terms that their HIV (viral load) is undetectable.
TasP requires population screening approaches to identify HIV-infected people at the earliest possible opportunity and start them on suppressive antiretroviral therapy to prevent further transmission. This potentially optimal HIV-testing setting (free-of-charge, easily accessible, short waiting times) identified HIV-infected individuals with high viral loads and relatively low CD4 counts. More research is needed to encourage sexually active adults to cyclically present themselves for HIV testing. Moreover, viral load estimation at the time of HIV diagnosis might be a better measure than CD4 count when making decisions about initiation of ART in the context of TaSP. Our data suggest that for TasP to succeed, ART treatment initiation criteria require revision, with a view to commencing therapy irrespective of CD4 counts.
Acknowledgments
ZAZI patients for participating in the study, Anna Mvambo for data management and ZAZI clinic staff for implementing the study protocol.
Author Contributions
Conceived and designed the experiments: SG TE GdB NM. Performed the experiments: SG NM GdB TE. Analyzed the data: KO. Contributed reagents/materials/analysis tools: SG NM GdB GG. Wrote the paper: SG KO RP GdB LM GG NM.
References
- 1. Cohen MS, Chen YQ, McCauley M, Gamble T, Hosseinipour MC, et al. (2011) Prevention of HIV-1 infection with early antiretroviral therapy. N Engl J Med 365: 493–505.
- 2. Granich R, Crowley S, Vitoria M, Lo YR, Souteyrand Y, et al. (2010) Highly active antiretroviral treatment for the prevention of HIV transmission. J Int AIDS Soc 13: 1.
- 3. Granich R, Crowley S, Vitoria M, Smyth C, Kahn JG, et al. (2010) Highly active antiretroviral treatment as prevention of HIV transmission: review of scientific evidence and update. Curr Opin HIV AIDS 5: 298–304.
- 4.
Department of Health. The South African Antiretroviral Treatment Guideline. Available: http://www.sahivsoc.org/practise-guidelines/sa-dept-of-health-guidelines. Accessed on 16th January 2014.
- 5. Meintjes G, Maartens G (2012) Guidelines for antiretroviral therapy in adults. Southern African Journal of HIV Medicine 13: 114–133.
- 6. Mellors JW, Munoz A, Giorgi JV, Margolick JB, Tassoni CJ, et al. (1997) Plasma viral load and CD4+ lymphocytes as prognostic markers of HIV-1 infection. Ann Intern Med 126: 946–954.
- 7. Hughes JP, Baeten JM, Lingappa JR, Magaret AS, Wald A, et al. (2012) Determinants of per-coital-act HIV-1 infectivity among African HIV-1-serodiscordant couples. J Infect Dis 205: 358–365.
- 8. Quinn TC, Wawer MJ, Sewankambo N, Serwadda D, Li C, et al. (2000) Viral load and heterosexual transmission of human immunodeficiency virus type 1. Rakai Project Study Group. N Engl J Med 342: 921–929.
- 9. Glencross D, Scott LE, Jani IV, Barnett D, Janossy G (2002) CD45-assisted PanLeucogating for accurate, cost-effective dual-platform CD4+ T-cell enumeration. Cytometry 50: 69–77.
- 10. Murnane PM, Hughes JP, Celum C, Lingappa JR, Mugo N, et al. (2012) Using plasma viral load to guide antiretroviral therapy initiation to prevent HIV-1 transmission. PLoS One 7: e51192.
- 11. Phillips A, Pezzotti P (2004) Short-term risk of AIDS according to current CD4 cell count and viral load in antiretroviral drug-naive individuals and those treated in the monotherapy era. AIDS 18: 51–58.
- 12. Farzadegan H, Hoover DR, Astemborski J, Lyles CM, Margolick JB, et al. (1998) Sex differences in HIV-1 viral load and progression to AIDS. Lancet 352: 1510–1514.
- 13. Prins M (1999) Do gender differences in CD4 cell counts matter? AIDS 13: 2361–2364.
- 14. Sterling TR, Vlahov D, Astemborski J, Hoover DR, Margolick JB, et al. (2001) Initial plasma HIV-1 RNA levels and progression to AIDS in women and men. N Engl J Med 344: 720–725.
- 15. Touloumi G, Pantazis N, Babiker AG, Walker SA, Katsarou O, et al. (2004) Differences in HIV RNA levels before the initiation of antiretroviral therapy among 1864 individuals with known HIV-1 seroconversion dates. AIDS 18: 1697–1705.
- 16. de Wolf F, Spijkerman I, Schellekens PT, Langendam M, Kuiken C, et al. (1997) AIDS prognosis based on HIV-1 RNA, CD4+ T-cell count and function: markers with reciprocal predictive value over time after seroconversion. AIDS 11: 1799–1806.