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BackgroundWe evaluated the prevalence of archived proviral drug resistance mutations (DRMs) associated with resistance to integrase strand transfer inhibitors (INSTIs) shortly before Botswana transitioned in 2016 to using dolutegravir (DTG)-based antiretroviral treatment in first-line regimens.MethodsWe used the Stanford University HIV drug resistance database to analyze INSTI-resistance associated mutations (RAMs) in a large representative population-based cohort of adults recruited in 30 geographically dispersed communities as part of the Botswana Combination Prevention Project (BCPP) cohort from 2013 to 2018. A total of 5,144 HIV-1 proviral DNA sequences were included in our analysis; 1,281 sequences were from antiretroviral therapy (ART)-naïve individuals and 3,863 sequences were from non-nucleoside reverse transcriptase inhibitor (NNRTI) ART-experienced individuals. None of the sequences were from DTG-ART experienced participants.ResultsThe overall prevalence of major INSTIs DRMs was 1.11% (95% CI 0.82–1.39%). The prevalence of INSTI DRMs in ART-naïve individuals was 1.64% (21/1,281) and 0.93% (36/3,863) in ART-experienced individuals. Major INSTI-RAMs detected in ART-naïve individuals were E138K (2/1,281; 0.16%), G140R (8/1,281;0.62%), E92G (2/1,281;0.16%), R263K (5/1,281; 0.4%), N155H (1/1,281; 0.08%), P145S (1/1,281;0.008%). Among the ART-experienced individuals, major INSTI RAMs detected were E138K (4/3,863; 0.10%), G140R (25/3,863;0.65%), G118R (2/3,863, 0.05%), R263K (4/3,863, 0.10%), T66I (1/3,863;0.03%), E138K + G140R (1/3,863, 0.03%|), G140R + R263K (1/3,863, 0.03%). High-level resistance to cabotegravir (CAB), elvitegravir (EVG), and raltegravir (RAL) was detected in 0.70, 0.16 and 0.06% of the individuals, respectively. Notably, bictegravir (BIC) and dolutegravir (DTG) showed no high-level resistance.ConclusionThe overall prevalence of archived INSTI RAMs in Botswana was low prior to transitioning to first-line DTG-based ART regimens, and did not differ between ART-naïve and ART-experienced individuals. Ongoing surveillance of INSTI DRMs in Botswana will allow for re-assessment of INSTI resistance risk following nationwide DTG rollout.

We investigated intra-host genetic evolution using two SARS-CoV-2 isolates from a fully vaccinated (primary schedule x2 doses of AstraZeneca plus a booster of Pfizer), >70-year-old woman with a history of lymphoma and hypertension who presented a SARS-CoV-2 infection for 3 weeks prior to death due to COVID-19. Two full genome sequences were determined from samples taken 13 days apart with both belonging to Pango lineage FL.2: the first detection of this Omicron sub-variant in Botswana. FL.2 is a sub-lineage of XBB.1.9.1. The repertoire of mutations and minority variants in the Spike protein differed between the two time points. Notably, we also observed deletions within the ORF1a and Membrane proteins; both regions are associated with high T-cell epitope density. The internal milieu of immune-suppressed individuals may accelerate SARS-CoV-2 evolution; hence, close monitoring is warranted.

Hepatitis delta virus (HDV) co-infections more often result in severe hepatitis compared to hepatitis B virus (HBV) infections alone. Despite a high HDV prevalence (7.1%), information regarding circulating HDV clades is very limited in Botswana. We extracted total nucleic acid from confirmed HDV-positive samples and quantified their viral load. We then sequenced the large hepatitis delta antigen (L-HDAg) using Oxford Nanopore Technology (ONT). Genotyping was performed using the HDV Database, and HDV mutation profiling was performed on AliView. All participants with HBV genotypic information belonged to sub-genotype A1, and 80% (4/5) of them had a higher HDV viral load and a lower HBV viral load. We sequenced 75% (9/12) of the HDV-positive samples, which belonged to HDV clade 8. A total of 54 mutations were discovered, with the most prevalent being Q148R (16%), D149P (16%) and G151D (16%). Known mutations such as S117A, K131R, R139K and G151D were detected, while the other mutations were novel. Our results reveal that HDV clade 8 is the predominant clade in Botswana. The significance of all mutations remains unclear. Future studies with a larger sample size to detect other HDV clades that might be circulating in Botswana and functionally characterize the detected mutations are warranted.

Background: Approximately 15–20 million people worldwide are infected with hepatitis delta virus (HDV), which is approximately 5 % of people with chronic hepatitis B virus (HBV). Sub-Saharan Africa has high HDV prevalence, leading to worse clinical outcomes among people who are HIV/HBV/HDV tri-infected. There are limited data on HDV prevalence among people with HIV (PWH) who are HBV-infected and uninfected in Botswana. We, therefore, determined HDV prevalence among PWH in Botswana. Methods: This was a retrospective cross-sectional study utilizing archived plasma samples from PWH with results for HBV markers such as hepatitis B surface antigen (HBsAg), hepatitis B core antibody (anti-HBc), immunoglobulin M antibody to hepatitis B core antigen (IgM anti-HBc) and hepatitis B e antigen (HBeAg). Samples were categorized according to their HBsAg status and screened for anti-HDV antibodies. Total nucleic acid was extracted from samples with a single positive anti-HDV result, and HDV ribonucleic acid (RNA) load was quantified using the Altona Diagnostic RealStar® HDV RT-PCR kit. Statistical analysis was performed using STATA version 14.0 where p-values

Abstract We used HIV-1C sequences to predict (in silico) resistance to 33 known broadly neutralizing antibodies (bnAbs) and evaluate the different HIV-1 Env characteristics that may affect virus neutralization. We analyzed proviral sequences from adults with documented HIV-1 seroconversion (N = 140) in Botswana (2013–2018). HIV-1 env sequences were used to predict bnAb resistance using bNAb-ReP, to determine the number of potential N-linked glycosylation sites (PNGS) and evaluate Env variable region characteristics (VC). We also assessed the presence of signature mutations that may affect bnAb sensitivity in vitro. We observe varied results for predicted bnAb resistance among our cohort. 3BNC117 showed high predicted resistance (72%) compared to intermediate levels of resistance to VRC01 (57%). We predict low resistance to PGDM100 and 10-1074 and no resistance to 4E10. No difference was observed in the frequency of PNGS by bNAb susceptibility patterns except for higher number of PNGs in V3 bnAb resistant strains. Associations of VC were observed for V1, V4 and V5 loop length and net charge. We also observed few mutations that have been reported to confer bnAb resistance in vitro. Our results support use of sequence data and machine learning tools to predict the best bnAbs to use within populations.

(1) Background: Hepatitis B virus (HBV) sequencing data are important for monitoring HBV evolution. We aimed to molecularly characterize HBV sequences from participants with HBV surface antigen-positive (HBsAg+) serology and occult hepatitis B infection (OBI+). (2) Methods: We utilized archived plasma samples from people living with human immunodeficiency virus (PLWH) in Botswana. HBV DNA was sequenced, genotyped and analyzed for mutations. We compared mutations from study sequences to those from previously generated HBV sequences in Botswana. The impact of OBI-associated mutations on protein function was assessed using the Protein Variation Effect Analyzer. (3) Results: Sequencing success was higher in HBsAg+ than in OBI+ samples [86/128 (67.2%) vs. 21/71 (29.2%)]. Overall, 93.5% (100/107) of sequences were genotype A1, 2.8% (3/107) were D3 and 3.7% (4/107) were E. We identified 13 escape mutations in 18/90 (20%) sequences with HBsAg coverage, with K122R having the highest frequency. The mutational profile of current sequences differed from previous Botswana HBV sequences, suggesting possible mutational changes over time. Mutations deemed to have an impact on protein function were tpQ6H, surfaceV194A and preCW28L. (4) Conclusions: We characterized HBV sequences from PLWH in Botswana. Escape mutations were prevalent and were not associated with OBI. Longitudinal HBV studies are needed to investigate HBV natural evolution.

(1) Background: we determined the prevalence of the hepatitis B virus (HBV) amongst people without human immunodeficiency virus (HIV) in rural and peri-urban areas in Botswana. (2) Methods: We screened for the hepatitis B surface antigen (HBsAg) from archived plasma samples of people without HIV (n = 2135) randomly selected from the Botswana Combination Prevention Program (BCPP) (2013–2018). We sequenced 415 bp of the surface region using BigDye sequencing chemistry. (3) Results: The median age of participants was 31 (IQR: 24–46) and 64% (1360/2135) were female. HBV prevalence was 4.0% (86/2135) [95% CI: 3.3–4.9]) and ranged between 0–9.2%. Older participants (>35 years) had increased odds of HBV positivity (OR: 1.94; 95% CI: [1.32–2.86]; p = 0.001). Thirteen samples were sequenced and seven (53.8%) were genotype A, three (23.1%) were genotype D and genotype E each. Clinically significant mutations were identified in the surface region, but no classic drug resistance mutations were identified. (4) Conclusions: We report an HBV prevalence of 4.0% (95% CI 3.3–4.9) among people without HIV in rural and peri-urban communities in Botswana with varying rates in different communities. A comprehensive national HBV program is required in Botswana to guide HBV prevention, testing and management.

Abstract We sought to investigate whether SARS‐CoV‐2 was present, and to perform full‐length genomic sequencing, in a 5‐year‐old male crossbreed dog from Gaborone, Botswana that presented overt clinical signs (flu‐like symptoms, dry hacking cough and mild dyspnoea). It was only sampled a posteriori, because three adult owners were diagnosed with SARS‐CoV‐2 infection. Next‐generation sequencing based on Oxford Nanopore Technology (ONT) was performed on amplicons that were generated using a reverse transcriptase real‐time polymerase chain reaction (RT‐qPCR) of confirmed positive SARS‐CoV‐2 nasopharyngeal and buccal swabs, as well as a bronchoalveolar lavage with mean real cycle threshold (qCt) value of 36 based on the Nucleocapsid (N) gene. Descriptive comparisons to known sequences in Botswana and internationally were made using mutation profiling analysis and phylogenetic inferences. Human samples were not available. A near‐full length SARS‐CoV‐2 genome (∼90% coverage) was successfully genotyped and classified under clade 20 O and Pango‐Lineage AY.43 (Pango v.4.0.6 PLEARN‐v1.3; 2022‐04‐21), which is a sublineage of the Delta variant of concern (VOC) (formerly called B.1.617.2, first detected in India). We did not identify novel mutations that may be used to distinguish SARS‐CoV‐2 isolates from the dog and humans. In addition to Spike (S) region mutation profiling, we performed phylogenetic analysis including 30 Delta sequences publicly available reference also isolated from dogs. In addition, we performed another exploratory analysis to investigate the phylogenetic relatedness of sequence isolated from dog with those from humans in Botswana (n = 1303) as of 31 March 2022 and of same sublineage. Expectedly, the sequence formed a cluster with Delta sublineages – AY.43, AY.116 and B.1.617.2 – circulating in same time frame. This is the first documented report of human‐associated SARS‐CoV‐2 infection in a dog in Botswana. Although the direction of transmission remains unknown, this study further affirms the need for monitoring pets during different COVID‐19 waves for possible clinically relevant SARS‐CoV‐2 transmissions between species.

BackgroundThe WHO strategy for cervical cancer elimination strives to achieve 70% coverage with high-performance cervical screening. While few low- and middle-income countries have achieved this, high-risk human papillomavirus (hrHPV) self-testing creates the possibility to rapidly upscale access to high-performance cervical screening across resource settings. However, effective hrHPV screening requires linkage to follow-up, which has been variable in prior studies. This study developed and tested an implementation strategy aimed at improving screening and linkage to follow-up care in South East District in Botswana.MethodsThis study performed primary hrHPV self-testing; those with positive results were referred for a triage visit. Withdrawals for any reason, loss-to follow-up between hrHPV test and triage visit, and number of call attempts to give hrHPV results were also documented. Acceptability of the program to patients was measured as the proportion of patients who completed a triage visit when indicated, meeting the a priori threshold of 80%. Feasibility was defined as the proportion of participants receiving the results and attending follow-up. To assess the associations between participant characteristics and loss-to-follow-up we used log-binomial regressions to estimate risk ratios and 95% confidence intervals (CI).ResultsEnrollment of 3,000 women occurred from February 2021 to August 2022. In total, 10 participants withdrew and an additional 33 were determined ineligible after consent, leaving a final cohort of 2,957 participants who underwent self-swab hrHPV testing. Half (50%) of participants tested positive for hrHPV and nearly all (98%) of participants received their hrHPV results, primarily via telephone. Few calls to participants were required to communicate results: 2,397 (82%) required one call, 386 (13%) required 2 calls, and only 151 (5%) required 3–5 calls. The median time from specimen collection to participant receiving results was 44 days (IQR, 27–65). Of all hrHPV positive participants, 1,328 (90%) attended a triage visit.DiscussionIn a large cohort we had low loss-to-follow-up of 10%, indicating that the strategy is acceptable. Telephonic results reporting was associated with high screening completion, required few calls to participants, and supports the feasibility of hrHPV self-testing in primary care followed by interval triage.

IntroductionMonthly intravenous infusion of broadly neutralizing monoclonal antibodies may be an attractive alternative to daily oral antiretroviral treatment for children living with HIV. However, acceptability among caregivers remains unknown.MethodsWe evaluated monthly infusion of dual bNAbs (VRCO1LS and 10-1074) as a treatment alternative to ART among children participating in the Tatelo Study in Botswana. Eligible children aged 2-5 years received 8-32 weeks of bNAbs overlapping with ART, and up to 24 weeks of bNAbs alone as monthly intravenous infusion. Using closed-ended questionnaires, we evaluated caregiver acceptability of each treatment strategy prior to the first bNAb administration visit (pre-intervention) and after the completion of the final bNAb administration visit (post-intervention).ResultsTwenty-five children completed the intervention phase of the study, and acceptability data were available from 24 caregivers at both time points. Responses were provided by the child's mother at both visits (60%), an extended family member at both visits (28%), or a combination of mother and an extended family member (12%). Caregiver acceptance of monthly bNAb infusions was extremely high both pre-and post-intervention, with 21/24 (87.5%) preferring bNAbs to ART pre-intervention, and 21/25 (84%) preferring bNAbs post-intervention. While no caregiver preferred ART pre-intervention, 2/25 preferred it post-intervention. Pre-intervention, 3 (13%) caregivers had no preference between monthly bNAbs or daily ART, and 2 (8%) had no preference post-intervention. Pre-intervention, the most common reasons for preferring bNAbs over ART were the perception that bNAbs were better at suppressing the virus than ART (n = 10) and the fact that infusions were dosed once monthly compared to daily ART (n = 9). Post-intervention, no dominant reason for preferring bNAbs over ART emerged from caregivers.ConclusionsMonthly intravenous bNAb infusions were highly acceptable to caregivers of children with HIV in Botswana and preferred over standard ART by the majority of caregivers.Clinical trial numberNCT03707977.

ABSTRACT There are limited data on the prevalence of fostemsavir (FTR) resistance-associated polymorphisms in people with HIV in Botswana. We sought to determine the prevalence of FTR resistance-associated polymorphisms in HIV-1 subtype C sequences from antiretroviral therapy (ART)-naïve and ART-experienced individuals in Botswana. Previously reported FTR resistance-associated polymorphisms from literature were surveyed from HIV-1C proviral sequences generated from a large HIV-1 population-based cohort enrolled between 2013 and 2018. Sequences from ART-naïve and ART-experienced individuals were included in the analysis. A total of 6,078 participants with gp120 sequences were included in this study, and 6,030 (99.2%) had known ART status; 1,282 (21.3%) were from ART-naïve individuals, while 4,748 (78.7%) were from individuals on ART at study enrollment. Viral load (VL) data were available for 4,739 (99.8%) ART-experienced individuals, of whom 4,526 (95.5%) were suppressed and 213 (4.5%) had virologic failure (VF) (VL >400). Among those with VF and ART naive, the overall prevalence of FTR resistance was 13.3% (95% CI 11.6%–15.1%) and did not differ between ART-experienced with VF individuals (29/213, 13.6%) and ART-naïve individuals (170/1,282, 13.3%) (P-value = 0.9). The most predominant mutations (prevalence ≥1.0%) were M434I (9.8%), M475I (5.9%), and M426L (1.1%). The overall prevalence of FTR polymorphisms was similar in both ART-naïve and ART-experienced individuals with VF in a setting with no prior FTR exposure. We recommend further studies on the phenotypic impact of these polymorphisms to guide how to monitor for FTR resistance. (This study has been registered at ClinicalTrials.gov under registration no. NCT01965470.) IMPORTANCE Fostemsavir (FTR) is a newly licensed antiretroviral drug that has been shown to have activity against HIV-1. The mechanism of action of FTR is different from all currently available antiretrovirals (ARVs), and as such, it offers hope for HIV-1 suppression in those people with HIV (PWH) who harbor HIV-1 variants with drug resistance mutations to currently used ARVs. Using 6,030 HIV-1 sequences covering the HIV-1 envelope from PWH in Botswana who are antiretroviral therapy (ART) naïve as well as those who are failing ART, we explored the sequences for FTR resistance-associated polymorphisms. We found the prevalence of FTR polymorphisms to be similar in both ART-naïve and ART-experienced individuals with VF in this setting, with no prior FTR exposure. Further studies on the phenotypic impact of these polymorphisms are warranted to guide how to monitor for FTR resistance.

Abstract Background Low- and middle-income countries (LMICs) account for nearly 85% of the global cervical cancer burden, yet have the least access to high-performance screening. International guidelines recommend human papillomavirus testing (HPV) as primary screening, yet implementation is inhibited by the cost of HPV testing. Atila AmpFire® HPV Assay (AmpFire) is both affordable and easy to use, and offers individual genotyping. The objective of this study was to compare the performance of the AmpFire HPV assay to the Xpert® HPV assay in detection of both HPV and clinically significant cervical disease. Methods We utilized stored cervical specimens from a prospective cohort study of women living with human immunodeficiency virus (HIV) in Botswana conducted from May to July 2018. Positive and negative percent agreement was calculated for the AmpFire and Xpert assays, as was detection of high-grade cervical dysplasia. Results 63 stored cervical specimens had detectable DNA after thawing and were included in the analysis. The positive percent agreement was 91.2% (95%CI 76.3–98.1) and negative percent agreement was 79.3% (95% CI 60.3–92.0). Six cases positive by AmpFire but negative by Xpert were HPV genotypes 35, 52 (n = 2), 58, 68, and co-infection with HPV 45 and 68. Both Xpert and AmpFire assays detected HPV in all 10 samples of women who had high-grade cervical dysplasia. Conclusions The AmpFire HPV assay demonstrated excellent analytic performance in both detection of HPV and clinically significant cervical disease. AmpFire HPV is a promising option to increase access to affordable, type-specific HPV screening for cervical cancer in LMICs.

We evaluated subsequent virologic outcomes in individuals experiencing low-level virem ia (LLV) on dolutegravir (DTG)-based first-line antiretroviral therapy (ART) in Botswana. We used a national dataset from 50,742 adults who initiated on DTG-based first-line ART from June 2016–December 2022. Individuals with at least two viral load (VL) measurements post three months on DTG-based first-line ART were evaluated for first and subsequent episodes of LLV (VL:51–999 copies/mL). LLV was sub-categorized as low-LLV (51–200 copies/mL), medium-LLV (201–400 copies/mL) and high-LLV (401–999 copies/mL). The study outcome was virologic failure (VF) (VL ≥ 1000 copies/mL): virologic non-suppression defined as single-VF and confirmed-VF defined as two-consecutive VF measurements after an initial VL < 1000 copies/mL. Cox regression analysis identified predictive factors of subsequent VF. The prevalence of LLV was only statistically different at timepoints >6–12 (2.8%) and >12–24 (3.9%) (p-value < 0.01). LLV was strongly associated with both virologic non-suppression (adjusted hazards ratio [aHR] = 2.6; 95% CI: 2.2–3.3, p-value ≤ 0.001) and confirmed VF (aHR = 2.5; 95% CI: 2.4–2.7, p-value ≤ 0.001) compared to initially virally suppressed PLWH. High-LLV (HR = 3.3; 95% CI: 2.9–3.6) and persistent-LLV (HR = 6.6; 95% CI: 4.9–8.9) were associated with an increased hazard for virologic non-suppression than low-LLV and a single-LLV episode, respectively. In a national cohort of PLWH on DTG-based first-line ART, LLV > 400 copies/mL and persistent-LLV had a stronger association with VF. Frequent VL testing and adherence support are warranted for individuals with VL > 50 copies/mL.

(1) Background: We aimed to determine the prevalence of hepatitis B virus (HBV) resistance-associated mutations (RAMs) in people with HBV and human immunodeficiency virus (HBV/HIV) in Botswana. (2) Methods: We sequenced HBV deoxyribonucleic acid (DNA) from participants with HBV/HIV from the Botswana Combination Prevention Project study (2013–2018) using the Oxford Nanopore GridION platform. Consensus sequences were analyzed for genotypic and mutational profiles. (3) Results: Overall, 98 HBV sequences had evaluable reverse transcriptase region coverage. The median participant age was 43 years (IQR: 37, 49) and 66/98 (67.4%) were female. Most participants, i.e., 86/98 (87.8%) had suppressed HIV viral load (VL). HBV RAMs were identified in 61/98 (62.2%) participants. Most RAMs were in positions 204 (60.3%), 180 (50.5%), and 173 (33.3%), mostly associated with lamivudine resistance. The triple mutations rtM204V/L180M/V173L were the most predominant (17/61 [27.9%]). Most participants (96.7%) with RAMs were on antiretroviral therapy for a median duration of 7.5 years (IQR: 4.8, 10.5). Approximately 27.9% (17/61) of participants with RAMs had undetectable HBV VL, 50.8% (31/61) had VL < 2000 IU/mL, and 13/61 (21.3%) had VL ≥ 2000 IU/mL. (4) Conclusions: The high prevalence of lamivudine RAMs discourages the use of ART regimens with 3TC as the only HBV-active drug in people with HIV/HBV.

Background: Limited data exist on the differential risk of HIV acquisition between infants born preterm versus those born at term to women living with HIV (WLHIV). With a reported increase in preterm delivery among pregnant WLHIV, understanding the risk of vertical transmission of HIV in preterm infants can inform strategies to optimise the timing of diagnostic testing, antiretroviral prophylaxis, and infant feeding. Objectives: To describe the prevalence and timing of HIV acquisition, in utero versus perinatal, among infants with perinatal HIV exposure born prior to 37 weeks completed gestation age compared to those born at term in the Botswana-based Mpepu study and explore predictors of infant HIV acquisition. Method: Using data extracted from the Mpepu study, we describe the prevalence, timing and risk factors for HIV acquisition in infants born preterm versus those born at term. Fisher exact testing was used to test for differences in prevalence and timing of HIV and a multivariable logistic regression model was used to assess risk factors for infant HIV acquisition. Results: 2866 infants born to WLHIV were included in this secondary analysis. 532 (19%) were born preterm. There was no observed difference in the prevalence of HIV acquisition among infants born preterm versus at term overall (0.8% vs 0.6%, P = 0.54), at birth (0.2% vs 0.3%, P = 1.00) or between 14 and 34 days post-delivery (0.6% vs 0.3%, P = 0.41). The absence of maternal antiretroviral use during pregnancy significantly predicted infant HIV acquisition, with the risk of HIV acquisition reduced by 96% among infants whose mothers were taking antiretroviral treatment (ART) during pregnancy (adjusted odds ratio: 0.003, confidence interval: 0.01–0.02, P 0.001). Conclusion: There was no observed increase of in utero and peripartum HIV acquisition among infants born preterm following foetal exposure to HIV compared to those born at term.

Abstract Introduction In December 2019, the Botswana government expanded free antiretroviral therapy (ART) to include non‐citizens. We evaluated the impact of this policy change on antenatal care (ANC), antiretroviral therapy coverage and adverse birth outcomes. Methods The Tsepamo Surveillance study collects data at up to 18 delivery sites in Botswana. We compared outcomes in citizens and non‐citizens living with HIV before and after antiretroviral therapy expansion to non‐citizens. Adverse birth outcomes included preterm delivery (PTD)

Background: The persistence of HIV-1-infected cells during antiretroviral therapy is well documented but may be modulated by early initiation of antiretroviral therapy in infants. Methods: Here, we longitudinally analyzed the proviral landscape in nine infants with vertical HIV-1 infection from Mozambique over a median period of 24 months, using single-genome, near full-length, next-generation proviral sequencing. Results: We observed a rapid decline in the frequency of intact proviruses, leading to a disproportional under-representation of intact HIV-1 sequences within the total number of HIV-1 DNA sequences after 12-24 months of therapy. In addition, proviral integration site profiling in one infant demonstrated clonal expansion of infected cells harboring intact proviruses and indicated that viral rebound was associated with an integration site profile dominated by intact proviruses integrated into genic and accessible chromatin locations. Conclusion: Together, these results permit rare insight into the evolution of the HIV-1 reservoir in infants infected with HIV-1 and suggest that the rapid decline of intact proviruses, relative to defective proviruses, may be attributed to a higher vulnerability of genome-intact proviruses to antiviral immunity. Technologies to analyze combinations of intact proviral sequences and corresponding integration sites permit a high-resolution analysis of HIV-1 reservoir cells after early antiretroviral treatment initiation in infants.

ABSTRACT: Objectives: There are limited data on the prevalence of doravirine (DOR)-associated drug resistance mutations in people with HIV (PWH) in Botswana. This cross-sectional, retrospective study aimed to explore the prevalence of DOR-associated resistance mutations among ART-naïve and -experienced PWH in Botswana enrolled in the population-based Botswana Combination Prevention Project (BCPP). Methods: A total of 6078 HIV-1C pol sequences were analysed for DOR-associated resistance mutations using the Stanford HIV drug resistance database, and their levels were predicted according to the Stanford DRM penalty scores and resistance interpretation. Virologic failure was defined as HIV-1 RNA load (VL) >400 copies/mL. Results: Among 6078 PWH, 5999 (99%) had known ART status, and 4529/5999 (79%) were on ART at time of sampling. The suppression rate among ART-experienced was 4517/4729 (96%). The overall prevalence of any DOR-associated resistance mutations was 181/1473 (12.3% [95% confidence interval {CI}: 10.7–14.1]); by ART status: 42/212 (19.8% [95% CI: 14.7–25.4]) among ART-failing individuals (VL ≥400 copies/mL) and 139/1261 (11.0% [95% CI: 9.3–12.9]) among ART-naïve individuals (P < 0.01). Intermediate DOR-associated resistance mutations were observed in 106/1261 (7.8% [95% CI: 6.9–10.1]) in ART-naïve individuals and 29/212 (13.7% [95% CI: 9.4–8.5]) among ART-experienced participants (P < 0.01). High-level DOR-associated resistance mutations were observed in 33/1261 (2.6% [95% CI: 1.8–3.7]) among ART-naïve and 13/212 (6.1% [95% CI: 3.6–10.8]) among ART-failing PWH (P < 0.01). PWH failing ART with at least one EFV/NVP-associated resistance mutation had high prevalence 13/67 (19.4%) of high-level DOR-associated resistance mutations. Conclusion: DOR-associated mutations were rare (11.0%) among ART-naive PWH but present in 62.7% of Botswana individuals who failed NNRTI-based ART with at least one EFV/NVP-associated resistance mutation. Testing for HIV drug resistance should underpin the use of DOR in PWH who have taken first-generation NNRTIs.

BackgroundWomen living with HIV-1 (WLHIV) are at higher risk of having an adverse birth outcome, but the underlying mechanism(s) are unknown. We hypothesized that HIV-associated endothelial activation could adversely impact placental function and lead to impaired fetal growth or stillbirth.MethodsWe used stored samples from WLHIV and HIV-negative women who had enrolled during pregnancy in the observational Botswana Tshipidi cohort. Written informed consent was obtained from the participants. We measured plasma levels of markers of endothelial activation (soluble vascular adhesion molecule 1 [VCAM-1], intercellular adhesion molecule 1 [ICAM-1] and E-selectin) from samples taken during pregnancy. We compared log10 biomarker levels by maternal HIV status and by the timing of ART initiation (ART prior to conception vs. during pregnancy; ART prior to sample collection vs. no ART prior to sampling) using t-tests and the Kruskal-Wallis rank test. We evaluated the association between these biomarkers and adverse birth outcomes (composite of stillbirth or small for gestational age [SGA]) using univariate and multivariate log-binomial regression controlling for maternal age (continuous) and timing of ART start. We also used generalized linear models (GLM) to evaluate the association between continuous birthweight (in grams) and gestational age (in weeks) and markers of endothelial dysfunction, adjusting for maternal age (continuous) and timing of ART relative to sample collection.ResultsSpecimens collected before delivery were available for 414 women (372 WLHIV and 42 HIV-negative women), with a median age of 28 years and median gestational age at sample collection of 30 weeks (range 26, 35 weeks). WLHIV had significantly higher median VCAM1 (p = 0.002) than HIV-negative women, but HIV-negative women had higher median ICAM1 (p = 0.01); e-Selectin levels did not differ by maternal HIV status. Women starting ART during pregnancy had higher log10 VCAM1 levels than those on ART before conception, regardless of whether the sample was collected before (p = 0.02) or after (p = 0.03) ART initiation. However, ICAM1 and e-Selectin did not differ significantly by ART status or ART timing. Ninety-eight women (91 WLHIV and 7 HIV-negative), or 9 (2%) and 89 (22%) included in this study, had a stillborn or SGA baby respectively. Univariate and adjusted analyses did not show significant associations between levels of any of the biomarkers with these adverse birth outcomes. However, lower birthweight (p = 0.03) and lower gestational age at delivery were associated e-Selectin and ICAM (p = 0.008), respectively.ConclusionMaternal HIV infection and lack of ART (or recent ART initiation) were associated with one marker of greater endothelial activation (VCAM-1), but not with other markers (ICAM-1 nor E-selectin) in pregnancy. e-Selectin was associated with lower birthweight and every unit increase in log ICAM-1 at delivery was associated with lower gestation age at delivery.

Abstract Introduction In Botswana, where almost all pregnant women known to have HIV receive antiretroviral therapy, a large proportion of vertical HIV transmission may occur among women with incident undiagnosed HIV infection during pregnancy. Botswana guidelines recommend repeat HIV testing every 3 months in pregnancy, with at least one test in the third trimester. We evaluated the rate of repeat HIV testing, calculated HIV incidence during pregnancy and estimated missed seroconversions. Methods In the Botswana Tsepamo Study, we abstracted HIV test dates and results from obstetric records of all women who delivered at maternity wards in 18 communities between 7th May 2017 and 20th August 2021. We defined seroconversion as an initial negative/indeterminate HIV test in pregnancy followed by a positive test during pregnancy/at delivery. The incidence rate (IR) of seroconversion was calculated among women with > = 2 known test dates. Missed seroconversions were estimated among women without a test in the third trimester by applying the IR to the time after the last HIV test until delivery. Results Among 103,529 women delivering in the study period testing negative at the first test and with known conception and HIV test dates, 29,085 (28%) were tested in one trimester of pregnancy, 73,156 (71%) were tested in ≥ 2 trimesters of pregnancy and 9628 (9%) had a test in all trimesters. A total of 78,162 (75%) women had a third‐trimester test. There were 223 seroconversions (2.58/1000 pregnancies, 0.26%) among those with ≥ 2 known HIV test dates, yielding an IR of 0.69/100 person‐years. Among 25,289 women who did not have a test in the third trimester, we estimate approximately 58 seroconversions may have been missed during pregnancy due to a lack of repeat testing. Factors associated with seroconversion during pregnancy included younger age, less education and not being married. Conclusions More than two‐thirds of women had repeat HIV testing in pregnancy and HIV incidence was low. However, an estimated 21% of seroconversions in pregnancy were likely missed due to a lack of re‐testing. To reach the goal of zero new paediatric HIV infections, Botswana will need to intensify repeat HIV testing in the third trimester of pregnancy.

Abstract Background Botswana updated its antiretroviral treatment (ART) guidelines in May 2016 to support breastfeeding for women living with HIV (WLHIV) on ART who have documented HIV RNA suppression during pregnancy. Methods From September 2016 to March 2019, we evaluated feeding method at discharge among WLHIV at eight government maternity wards in Botswana within the Tsepamo Study. We validated the recorded feeding method on the obstetric record using the prevention of mother-to-child transmission of HIV (PMTCT) counsellor report, infant formula dispensing log or through direct observation. Available HIV RNA results were recorded from the obstetric record, and from outpatient HIV records (starting February 2018). In a subset of participants, we used electronic laboratory records to verify whether an HIV RNA test had occurred. Univariable and multivariable logistic regression analyses were performed to identify factors associated with infant feeding choice. Results Among 13,354 WLHIV who had a validated feeding method at discharge, 5303 (39.7%) chose to breastfeed and 8051 (60.3%) chose to formula feed. Women who had a documented HIV RNA result in the obstetric record available to healthcare providers at delivery were more likely to breastfeed (50.8%) compared to women who did not have a documented HIV RNA result (35.4%) (aOR 0.59; 95% CI 0.54, 0.65). Among women with documented HIV RNA, 2711 (94.6%) were virally suppressed ( 400 copies/mL, and 134 (27.4%) of 489 women with no reported ART use. A sub-analysis of electronic laboratory records among 150 women without a recorded result on the obstetric record revealed that 93 (62%) women had an HIV RNA test during pregnancy. Conclusions In a setting of long-standing use of suppressive ART, with majority of WLHIV on ART from the time of conception, requiring documentation of HIV RNA suppression in the obstetric record to inform infant feeding decisions is a barrier to breastfeeding but unlikely to prevent a substantial amount of HIV transmission.

Introduction Sub-Saharan Africa has the largest number of people with HIV, one of the most severe burdens of adverse birth outcomes globally and particular vulnerability to climate change. We examined associations between seasonality and adverse birth outcomes among women with and without HIV in a large geographically representative birth outcomes surveillance study in Botswana from 2015 to 2018.Methods We evaluated stillbirth, preterm delivery, very preterm delivery, small for gestational age (SGA), very SGA, and combined endpoints of any adverse or severe birth outcome. We estimated the risk of each outcome by month and year of delivery, and adjusted risks ratios (ARRs) of outcomes during the early wet (1 November–15 January), late wet (16 January–31 March) and early dry (1 April–15 July) seasons, compared with the late dry (16 July–31 October) season. Analyses were conducted overall and separately by HIV status.Results Among 73 178 women (24% with HIV), the risk of all adverse birth outcomes peaked in November–January and reached low points in September. Compared with the late dry season, the ARRs for any adverse birth outcome were 1.03 (95% CI 1.00 to 1.06) for the early dry season, 1.08 (95% CI 1.04 to 1.11) for the early wet season and 1.07 (95% CI 1.03 to 1.10) for the late wet season. Comparing the early wet season to the late dry season, we found that ARRs for stillbirth and very preterm delivery were higher in women with HIV (1.23, 95% CI 0.96 to 1.59, and 1.33, 95% CI 1.10 to 1.62, respectively) than in women without HIV (1.07, 95% CI 0.91 to 1.26, and 1.19, 95% CI 1.04 to 1.36, respectively).Conclusions We identified a modest association between seasonality and adverse birth outcomes in Botswana, which was greatest among women with HIV. Understanding seasonal patterns of adverse birth outcomes and the role of HIV status may allow for mitigation of their impact in the face of seasonal extremes related to climate change.

Various host factors may impact within-host pathogen evolution. Here, the authors develop a Bayesian approach for identifying host-pathogen interactions using large data sets of pathogen diversity, and apply it to investigate HLA-induced selection in the HIV-1 genome.

BackgroundBotswana introduced the HBV vaccine at birth for all newborns in 2000. To the best of our knowledge, since the introduction of HBV vaccination, there have been limited data for vaccine response to HBV and its impact on early childhood HBV infections among children HIV exposed but uninfected in Botswana.AimsTo determine the prevalence of hepatitis B surface antigen (HBsAg) and HBV vaccine response in 18 months old children HIV exposed but uninfected in Botswana.MethodsStored plasma samples from 304 children at 18 months of age and 287 mothers from delivery were tested for HBsAg. Mothers with positive HBsAg had HBV DNA level tested, and their HBV genotypes were determined by amplifying a 415-base pair (bp) region of the surface gene. Plasma samples from children exposed to HIV were tested for hepatitis B surface antibody (anti-HBs) titers.ResultsNo children (0 of 304) were positive for HBsAg at 18 months while 5 (1.74%) of 287 HIV-positive mothers were HBsAg positive. Four of the HBsAg positive mothers were infected with genotype A1, while 1 was infected with genotype E. The median anti-HBs titer in children was 174 mIU/mL [QR: 70, 457]. Three (1.1%) of 269 children had an inadequate vaccine response (ConclusionNo HBsAg positivity was identified in a cohort of children HIV exposed but uninfected. The absence of HBsAg positives was associated with good HBV vaccine responses and low maternal HBsAg prevalence in Botswana.

ObjectiveHIV-infected women on antiretroviral therapy have a higher risk of preterm birth than HIV-uninfected women in Botswana. To better understand the mechanism for preterm birth among HIV-infected women, we evaluated whether mid-trimester cervical length differed by HIV status as cervical shortening is associated with an increased risk for preterm birth.MethodsWe conducted a prospective cohort study among pregnant women receiving care at the Scottish Livingstone Hospital in Molepolole, Botswana. Consecutive women referred for routine obstetrical ultrasound were consented and enrolled if between 22w0d and 24w6d by ultrasound biometry. Blinded to maternal HIV status, an obstetrician measured transvaginal cervical length using standardized criteria. Cervical length, as well as the proportion of women with a short cervix (ResultsBetween April 2016 and April 2017, 853 women presenting for obstetric ultrasound were screened, 187 (22%) met eligibility criteria, and 179 (96%) were enrolled. Of those enrolled, 50 (28%) were HIV-infected (86% on antiretroviral therapy), 127 (71%) were HIV-uninfected, and 2 (1%) had unknown HIV status. There was no significant difference in mean cervical length between HIV-infected and HIV-uninfected women (32mm vs 31mm, p = 0.21), or in the proportion with a short cervix (10% vs 14%, p = 0.44). Acceptability data was available for 115 women who underwent a transvaginal ultrasound exam. Of these, 112 of 115 (97%) women deemed the transvaginal scan acceptable.ConclusionsThe increased risk of preterm birth observed among HIV-infected women receiving antiretroviral therapy in Botswana is unlikely associated with mid-trimester cervical shortening. Further research is needed to understand the underlying mechanism for preterm birth among HIV-infected women.

BackgroundRotavirus vaccine (RV) and pneumococcal vaccine (PCV) decrease diarrheal and respiratory disease incidence and severity, but there are few data about the effects of these vaccines among HIV-exposed uninfected (HEU) children.MethodsWe recorded RV and PCV vaccination history in a placebo-controlled trial that studied the need for cotrimoxazole among HEU infants in Botswana (the Mpepu Study). We categorized infants by enrollment before or after the simultaneous April 2012 introduction of RV and PCV, and compared diagnoses of diarrhea and pneumonia (grade 3/4), hospitalizations, and deaths from both disease conditions through the 12-month study visit by vaccine era/status across two sites (a city and a village) by Kaplan-Meier estimates.ResultsTwo thousand six hundred and thirty-five HEU infants were included in this secondary analysis, of these 1689 (64%) were enrolled in Gaborone (344 pre-vaccine, 1345 vaccine) and 946 (36%) in Molepolole (209 pre-vaccine, 737 vaccine). We observed substantial reduction in hazard of hospitalization or death for reason of diarrhea and pneumonia in the vaccine era versus the pre-vaccine era in Molepolole (hazard ratio, HR = 0.44, 95% confidence interval, CI = 0.28, 0.71) with smaller reduction in Gaborone (HR = 0.91, 95% CI = 0.57, 1.45). Similar downward trends were observed for diagnoses of diarrhea and pneumonia separately during the vaccine versus pre-vaccine era.ConclusionsAlthough temporal confounding cannot be excluded, significant declines in the burden of diarrheal and respiratory illness were observed among HEU children in Botswana following the introduction of RV and PCV. RV and PCV may maximally benefit HEU children in rural areas with higher disease burden.

Background: Mortality among adult general medical admissions has been reported to be high across sub-Saharan Africa, yet there is a paucity of literature on causes of general medical inpatient mortality and quality-related factors that may contribute to the high incidence of deaths. Based on a prior study at our hospital as well as our clinical experience, death early in the hospitalization is common among patients admitted to the adult medical wards. Objective: Quantify early inpatient mortality and identify factors contributing to early in-hospital mortality of medical patients in a resource-limited hospital setting in Botswana. Methods: Twenty-seven cases of patients who died within 48 hours of admission to the general medical wards at Scottish Livingstone Hospital in Molepolole, Botswana from December 1, 2015–April 25, 2016 were retrospectively reviewed through a modified root cause analysis. Findings: Early in-hospital mortality was most frequently attributed to septic shock, identified in 20 (74%) of 27 cases. The most common care management problems were delay in administration of antibiotics (15, 56%), inappropriate fluid management (15, 56%), and deficient coordination of care (15, 56%). The most common contributing factors were inadequate provider knowledge and skills in 25 cases (93%), high complexity of presenting condition in 20 (74%), and inadequate communication between team members in 18 (67%). Conclusions: Poor patient outcomes in low-and middle-income countries like Botswana are often attributed to resource limitations. Our findings suggest that while early in-hospital mortality in such settings is associated with severe presenting conditions like septic shock, primary contributors to lack of better outcomes may be healthcare-provider and system-factors rather than lack of diagnostic and therapeutic resources. Low-cost interventions to improve knowledge, skills and communication through a focus on provider education and process improvement may provide the key to reducing early in-hospital mortality and improving hospitalization outcomes in this setting.

Summary: Background: Co-trimoxazole prophylaxis reduces mortality among HIV-infected children, but efficacy in HIV-exposed but uninfected (HEU) children in a non-malarial, low-breastfeeding setting with a low risk of mother-to-child transmission of HIV is unclear. Methods: HEU children in Botswana were randomly assigned to receive co-trimoxazole (100 mg/20 mg once daily until age 6 months and 200 mg/40 mg once daily thereafter) or placebo from age 14–34 days to age 15 months. Mothers chose whether to breastfeed or formula feed their children. Breastfed children were randomly assigned to breastfeeding for 6 months (Botswana guidelines) or 12 months (WHO guidelines). The primary outcome, analysed by a modified intention-to-treat approach, was cumulative child mortality from treatment assignment to age 18 months. We also assessed HIV-free survival by duration of breastfeeding. This trial is registered with ClinicalTrials.gov, number NCT01229761. Findings: From June 7, 2011, to April 2, 2015, 2848 HEU children were randomly assigned to receive co-trimoxazole (n=1423) or placebo (n=1425). The data and safety monitoring board stopped the study early because of a low likelihood of benefit with co-trimoxazole. Only 153 (5%) children were lost to follow-up (76 in the co-trimoxazole group and 77 in the placebo group), and 2053 (72%) received treatment continuously to age 15 months, death, or study closure. Mortality after the start of study treatment was similar in the two study groups: 30 children died in the co-trimoxazole group, compared with 34 in the placebo group (estimated mortality at 18 months 2·4% vs 2·6%; difference −0·2%, 95% CI −1·5 to 1·0, p=0·70). We saw no difference in hospital admissions between groups (12·5% in the co-trimoxazole group vs 17·4% in the placebo group, p=0·19) or grade 3–4 clinical adverse events (16·5% vs 18·4%, p=0·18). Grade 3–4 anaemia did not differ between groups (8·1% vs 8·3%, p=0·93), but grade 3–4 neutropenia was more frequent in the co-trimoxazole group than in the placebo group (8·1% vs 5·8%, p=0·03). More co-trimoxazole resistance in commensal Escherichia coli isolated from stool samples was seen in children aged 3 or 6 months in the co-trimoxazole group than in the placebo group (p=0·001 and p=0·01, respectively). 572 (20%) children were breastfed. HIV infection and mortality did not differ significantly by duration of breastfeeding (3·9% for 6 months vs 1·9% for 12 months, p=0·21). Interpretation: Prophylactic co-trimoxazole seems to offer no survival benefit among HEU children in non-malarial, low-breastfeeding areas with a low risk of mother-to-child transmission of HIV. Funding: US National Institutes of Health.

Background: The seroprevalence of human parvovirus-4 (PARV4) varies considerably by region. In sub-Saharan Africa, seroprevalence is high in the general population, but little is known about the transmission routes or the prevalence of coinfection with blood-borne viruses, HBV, HCV and HIV. Methods: To further explore the characteristics of PARV4 in this setting, with a particular focus on the prevalence and significance of coinfection, we screened a cohort of 695 individuals recruited from Durban and Kimberley (South Africa) and Gaborone (Botswana) for PARV4 IgG and DNA, as well as documenting HIV, HBV and HCV status. Results: Within these cohorts, 69% of subjects were HIV-positive. We identified no cases of HCV by PCR, but 7.4% were positive for HBsAg. PARV4 IgG was positive in 42%; seroprevalence was higher in adults (69%) compared to children (21%) (p

HLA class I polymorphism has a major influence on adult HIV disease progression. An important mechanism mediating this effect is the impact on viral replicative capacity (VRC) of the escape mutations selected in response to HLA-restricted CD8+ T-cell responses. Factors that contribute to slow progression in pediatric HIV infection are less well understood. We here investigate the relationship between VRC and disease progression in pediatric infection, and the effect of HLA on VRC and on disease outcome in adult and pediatric infection. Studying a South African cohort of >350 ART-naïve, HIV-infected children and their mothers, we first observed that pediatric disease progression is significantly correlated with VRC. As expected, VRCs in mother-child pairs were strongly correlated (p = 0.004). The impact of the protective HLA alleles, HLA-B*57, HLA-B*58:01 and HLA-B*81:01, resulted in significantly lower VRCs in adults (p

There is progressive concern about the evolving burden of morbidity and mortality caused by coinfection with HIV-1 and hepatitis B virus (HBV) in sub-Saharan Africa, but the epidemiology and impact of this problem are not well defined. We therefore set out to assimilate more information about the nature of HBV/HIV coinfection in this region by undertaking a retrospective observational study of southern African adult women. We used samples from previously recruited HIV-1 positive women attending antenatal clinics in three settings in South Africa and Botswana (n = 950) and added a small cohort of HIV-negative antenatal South African women for comparison (n = 72). We tested for HBsAg and followed up HBsAg-positive samples by testing for HBeAg, HBV DNA, HBV genotype, presence of drug-resistance associated mutations (RAMs) and HDV. We identified HBsAg in 72 individuals (7% of the whole cohort), of whom 27% were HBeAg-positive, and the majority HBV genotypes A1 and A2. We did not detect any HDV coinfection. HBV prevalence was significantly different between geographically distinct cohorts, but did not differ according to HIV status. Among adults from South Africa, HBV/HIV coinfected patients had lower CD4+ T cell counts compared to those with HIV-monoinfection (p = 0.02), but this finding was not replicated in the cohort from Botswana. Overall, these data provide a snapshot of the coinfection problem at the heart of the HIV/HBV co-epidemic, and are important to inform public health policy, resource allocation, education, surveillance and clinical care.

Recent studies in the SIV-macaque model of HIV infection suggest that Nef-specific CD8+ T-cell responses may mediate highly effective immune control of viraemia. In HIV infection Nef recognition dominates in acute infection, but in large cohort studies of chronically infected subjects, breadth of T cell responses to Nef has not been correlated with significant viraemic control. Improved disease outcomes have instead been associated with targeting Gag and, in some cases, Pol. However analyses of the breadth of Nef-specific T cell responses have been confounded by the extreme immunogenicity and multiple epitope overlap within the central regions of Nef, making discrimination of distinct responses impossible via IFN-gamma ELISPOT assays. Thus an alternative approach to assess Nef as an immune target is needed. Here, we show in a cohort of >700 individuals with chronic C-clade infection that >50% of HLA-B-selected polymorphisms within Nef are associated with a predicted fitness cost to the virus, and that HLA-B alleles that successfully drive selection within Nef are those linked with lower viral loads. Furthermore, the specific CD8+ T cell epitopes that are restricted by protective HLA Class I alleles correspond substantially to effective SIV-specific epitopes in Nef. Distinguishing such individual HIV-specific responses within Nef requires specific peptide-MHC I tetramers. Overall, these data suggest that CD8+ T cell targeting of certain specific Nef epitopes contributes to HIV suppression. These data suggest that a re-evaluation of the potential use of Nef in HIV T-cell vaccine candidates would be justified.

BACKGROUND:HLA class I genotype is a major determinant of the outcome of HIV infection, and the impact of certain alleles on HIV disease outcome is well studied. Recent studies have demonstrated that certain HLA class I alleles that are in linkage disequilibrium, such as HLA-A*74 and HLA-B*57, appear to function co-operatively to result in greater immune control of HIV than mediated by either single allele alone. We here investigate the extent to which HLA alleles--irrespective of linkage disequilibrium--function co-operatively. METHODOLOGY/PRINCIPAL FINDINGS:We here refined a computational approach to the analysis of >2000 subjects infected with C-clade HIV first to discern the individual effect of each allele on disease control, and second to identify pairs of alleles that mediate 'co-operative additive' effects, either to improve disease suppression or to contribute to immunological failure. We identified six pairs of HLA class I alleles that have a co-operative additive effect in mediating HIV disease control and four hazardous pairs of alleles that, occurring together, are predictive of worse disease outcomes (q

The first aim of the study is to assess the distribution of HIV-1 RNA levels in subtype C infection. Among 4,348 drug-naïve HIV-positive individuals participating in clinical studies in Botswana, the median baseline plasma HIV-1 RNA levels differed between the general population cohorts (4.1-4.2 log(10)) and cART-initiating cohorts (5.1-5.3 log(10)) by about one log(10). The proportion of individuals with high (> or = 50,000 (4.7 log(10)) copies/ml) HIV-1 RNA levels ranged from 24%-28% in the general HIV-positive population cohorts to 65%-83% in cART-initiating cohorts. The second aim is to estimate the proportion of individuals who maintain high HIV-1 RNA levels for an extended time and the duration of this period. For this analysis, we estimate the proportion of individuals who could be identified by repeated 6- vs. 12-month-interval HIV testing, as well as the potential reduction of HIV transmission time that can be achieved by testing and ARV treating. Longitudinal analysis of 42 seroconverters revealed that 33% (95% CI: 20%-50%) of individuals maintain high HIV-1 RNA levels for at least 180 days post seroconversion (p/s) and the median duration of high viral load period was 350 (269; 428) days p/s. We found that it would be possible to identify all HIV-infected individuals with viral load > or = 50,000 (4.7 log(10)) copies/ml using repeated six-month-interval HIV testing. Assuming individuals with high viral load initiate cART after being identified, the period of high transmissibility due to high viral load can potentially be reduced by 77% (95% CI: 71%-82%). Therefore, if HIV-infected individuals maintaining high levels of plasma HIV-1 RNA for extended period of time contribute disproportionally to HIV transmission, a modified "test-and-treat" strategy targeting such individuals by repeated HIV testing (followed by initiation of cART) might be a useful public health strategy for mitigating the HIV epidemic in some communities.