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1,183 result(s) for "Thomas, Katherine K."
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Heterosexual HIV-1 transmission after initiation of antiretroviral therapy: a prospective cohort analysis
High plasma HIV-1 RNA concentrations are associated with increased risk of HIV-1 transmission. Initiation of antiretroviral therapy (ART) reduces plasma HIV-1 concentrations. We aimed to assess the effect of ART use by patients infected with HIV-1 on risk of transmission to their uninfected partners. Participants in our prospective cohort analysis were from a randomised placebo-controlled trial that enrolled heterosexual African adults who were seropositive for both HIV-1 and herpes simplex virus type 2, and their HIV-1 seronegative partners. At enrolment, HIV-1 infected participants had CD4 counts of 250 cells per μL or greater and did not meet national guidelines for ART initiation; during 24 months of follow-up, CD4 counts were measured every 6 months and ART was initiated in accordance with national guidelines. Uninfected partners were tested for HIV-1 every 3 months. The primary outcome was genetically-linked HIV-1 transmission within the study partnership. We assessed rates of HIV-1 transmission by ART status of infected participants. 3381 couples were eligible for analysis. 349 (10%) participants with HIV-1 initiated ART during the study, at a median CD4 cell count of 198 (IQR 161–265) cells per μL. Only one of 103 genetically-linked HIV-1 transmissions was from an infected participant who had started ART, corresponding to transmission rates of 0·37 (95% CI 0·09–2·04) per 100 person-years in those who had initiated treatment and 2·24 (1·84–2·72) per 100 person-years in those who had not—a 92% reduction (adjusted incidence rate ratio 0·08, 95% CI 0·00–0·57, p=0·004). In participants not on ART, the highest HIV-1 transmission rate (8·79 per 100 person-years) was from those with CD4 cell counts lower than 200 cells per μL. In couples in whom the untreated HIV-1 infected partner had a CD4 cell count greater than 200 cells per μL, 66 (70%) of 94 transmissions occurred when plasma HIV-1 concentrations exceeded 50 000 copies per mL. Low CD4 cell counts and high plasma HIV-1 concentrations might guide use of ART to achieve an HIV-1 prevention benefit. Provision of ART to HIV-1 infected patients could be an effective strategy to achieve population-level reductions in HIV-1 transmission. Bill & Melinda Gates Foundation; US National Institutes of Health.
Sexual behaviour among women using intramuscular depot medroxyprogesterone acetate, a copper intrauterine device, or a levonorgestrel implant for contraception: Data from the ECHO randomized trial
Contraceptive use has complex effects on sexual behaviour and mood, including those related to reduced concerns about unintended pregnancy, direct hormonal effects and effects on endogenous sex hormones. We set out to obtain robust evidence on the relative effects of three contraceptive methods on sex behaviours, which is important for guiding contraceptive choice and future contraceptive developments. This is a secondary analysis of data from the Evidence for Contraceptive Options and HIV Outcomes (ECHO) randomized trial in which 7,829 HIV-uninfected women from 12 sites in Eswatini, Kenya, South Africa and Zambia seeking contraception were randomly assigned to intramuscular depot-medroxyprogesterone acetate (DMPA-IM), the copper intrauterine device (Cu-IUD) or the levonorgestrel (LNG) implant. Data collected for 12 to 18 months using 3-monthly behavioural questionnaires that relied on recall from the preceding 3 months, were used to estimate relative risk of post-baseline sex behaviours, as well as sexual desire and menstrual bleeding between randomized groups using modified Poisson regression. We observed small but generally consistent effects wherein DMPA-IM users reported lower prevalence of specified high risk sexual behaviours than implant users than Cu-IUD users (the '>' and '<' symbols indicate statistically significant differences): multiple sex partners 3.6% < 4.8% < 6.2% respectively; new sex partner 3.0% < 4.0% <5.3%; coital acts 16.45, 16.65, 17.12 (DMPA-IM < Cu-IUD); unprotected sex 65% < 68%, 70%; unprotected sex past 7 days 33% <36%, 37%; sex during vaginal bleeding 7.1%, 7.1% < 8.9%; no sex acts 4.1%, 3.8%, 3.4% (DMPA-IM > Cu-IUD); partner has sex with others 10% < 11%, 11%. The one exception was having any sex partner 96.5%, 96.9% < 97.4% (DMPA-IM < Cu-IUD). Decrease in sexual desire was reported by 1.6% > 1.1% >0.5%; amenorrhoea by 49% > 41% >12% and regular menstrual pattern by 26% <35% < 87% respectively. These findings suggest that women assigned to DMPA-IM may have a modest decrease in libido and sexual activity relative to the implant, and the implant relative to the Cu-IUD. We found more menstrual disturbance with DMPA-IM than with the implant (and as expected, both more than the Cu-IUD). These findings are important for informing the contraceptive choices of women and policymakers and highlight the need for robust comparison of the effects of other contraceptive methods as well.
Temporal Variability of Human Vaginal Bacteria and Relationship with Bacterial Vaginosis
Little is known about short-term bacterial fluctuations in the human vagina. This study used PCR to assess the variability in concentrations of key vaginal bacteria in healthy women and the immediate response to antibiotic treatment in women with bacterial vaginosis (BV). Twenty-two women assessed for BV using Amsel's criteria were evaluated daily for 7 or 14 days, then at 2, 3 and 4 weeks, using a panel of 11 bacterium-specific quantitative PCR assays. Participants with BV were treated with 5 days of intravaginal metronidazole. Participants without BV had vaginal biotas dominated by lactobacilli, whose levels fluctuated with menses. With onset of menstruation, quantities of Lactobacillus jensenii and Lactobacillus crispatus decreased and were found to be inversely related to Gardnerella vaginalis concentrations (p<0.001). Women with BV had a variety of fastidious bacteria whose concentrations dropped below detection thresholds 1-5 days after starting metronidazole. Recurrent BV was characterized by initial profound decreases of BV-associated bacteria after treatment followed by subsequent increases at relapse. The microbiota of the human vagina can be highly dynamic. Healthy women are colonized with Lactobacillus species, but levels can change dramatically over a month. Marked increases in G. vaginalis were observed during menses. Participants with BV have diverse communities of fastidious bacteria that are depleted by vaginal metronidazole therapy. Women with recurrent BV initially respond to antibiotic treatment with steep declines in bacterial concentrations, but these bacteria later reemerge, suggesting that antibiotic resistance in these bacteria is not an important factor mediating BV recurrence.
Adherence to Antiretroviral Prophylaxis for HIV Prevention: A Substudy Cohort within a Clinical Trial of Serodiscordant Couples in East Africa
Randomized clinical trials of oral antiretroviral pre-exposure prophylaxis (PrEP) for HIV prevention have widely divergent efficacy estimates, ranging from 0% to 75%. These discrepancies are likely due to differences in adherence. To our knowledge, no studies to date have examined the impact of improving adherence through monitoring and/or intervention, which may increase PrEP efficacy, or reported on objective behavioral measures of adherence, which can inform PrEP effectiveness and implementation. Within the Partners PrEP Study (a randomized placebo-controlled trial of oral tenofovir and emtricitabine/tenofovir among HIV-uninfected members of serodiscordant couples in Kenya and Uganda), we collected objective measures of PrEP adherence using unannounced home-based pill counts and electronic pill bottle monitoring. Participants received individual and couples-based adherence counseling at PrEP initiation and throughout the study; counseling was intensified if unannounced pill count adherence fell to <80%. Participants were followed monthly to provide study medication, adherence counseling, and HIV testing. A total of 1,147 HIV-uninfected participants were enrolled: 53% were male, median age was 34 years, and median partnership duration was 8.5 years. Fourteen HIV infections occurred among adherence study participants--all of whom were assigned to placebo (PrEP efficacy = 100%, 95% confidence interval 83.7%-100%, p<0.001). Median adherence was 99.1% (interquartile range [IQR] 96.9%-100%) by unannounced pill counts and 97.2% (90.6%-100%) by electronic monitoring over 807 person-years. Report of no sex or sex with another person besides the study partner, younger age, and heavy alcohol use were associated with <80% adherence; the first 6 months of PrEP use and polygamous marriage were associated with >80% adherence. Study limitations include potential shortcomings of the adherence measures and use of a convenience sample within the substudy cohort. The high PrEP adherence achieved in the setting of active adherence monitoring and counseling support was associated with a high degree of protection from HIV acquisition by the HIV-uninfected partner in heterosexual serodiscordant couples. Low PrEP adherence was associated with sexual behavior, alcohol use, younger age, and length of PrEP use. Please see later in the article for the Editors' Summary.
Standard Treatment Regimens for Nongonococcal Urethritis Have Similar but Declining Cure Rates: A Randomized Controlled Trial
Background. Azithromycin or doxycycline is recommended for nongonococcal urethritis (NGU); recent evidence suggests their efficacy has declined. We compared azithromycin and doxycycline in men with NGU, hypothesizing that azithromycin was more effective than doxycycline. Methods. From January 2007 to July 2011, English-speaking males ≥16 years, attending a sexually transmitted diseases clinic in Seattle, Washington, with NGU (visible urethral discharge or ≥5 polymorphonuclear leukocytes per high-power field [PMNs/HPF]) were eligible for this double-blind, parallel-group superiority trial. Participants received active azithromycin (1 g) + placebo doxycycline or active doxycycline (100 mg twice daily for 7 days) + placebo azithromycin. Urine was tested for Chlamydia trachomatis (CT), Mycoplasma genitalium (MG), Ureaplasma urealyticum biovar 2 (UU-2), and Trichomonas vaginalis (TV) using nucleic acid amplification tests. Clinical cure (<5 PMNs/HPF with or without urethral symptoms and absence of discharge) and microbiologic cure (negative tests for CT, MG, and/or UU-2) were determined after 3 weeks. Results. Of 606 men, 304 were randomized to azithromycin and 302 to doxycycline; CT, MG, TV, and UU-2 were detected in 24%, 13%, 2%, and 23%, respectively. In modified intent-to-treat analyses, 172 of 216 (80%; 95% confidence interval [CI], 74%–85%) receiving azithromycin and 157 of 206 (76%; 95% CI, 70%–82%) receiving doxycycline experienced clinical cure (P = .40). In pathogen-specific analyses, clinical cure did not differ by arm, nor did microbiologic cure differ for CT (86% vs 90%, P = .56), MG (40% vs 30%, P = .41), or UU-2 (75% vs 70%, P = .50). No unexpected adverse events occurred. Conclusions. Clinical and microbiologic cure rates for NGU were somewhat low and there was no significant difference between azithromycin and doxycycline. Mycoplasma genitalium treatment failure was extremely common. Clinical Trials Registration. NCT00358462.
Bacterial vaginosis associates with dysfunctional T cells and altered soluble immune factors in the cervicovaginal tract
BACKGROUNDBacterial vaginosis (BV) is a dysbiosis of the vaginal microbiome that is prevalent among reproductive-age females worldwide. Adverse health outcomes associated with BV include an increased risk of sexually acquired HIV, yet the immunological mechanisms underlying this association are not well understood.METHODSTo investigate BV-driven changes to cervicovaginal tract (CVT) and circulating T cell phenotypes, Kinga Study participants with or without BV provided vaginal tract (VT) and ectocervical (CX) tissue biopsies and PBMC samples.RESULTSHigh-parameter flow cytometry revealed an increased frequency of cervical CD4+ conventional T (Tconv) cells expressing CCR5 in BR+ versus BR- women. However, we found no difference in the number of CD3+CD4+CCR5+ cells in the CX or VT of BV+ versus BV- individuals, suggesting that BV-driven increased HIV susceptibility may not be solely attributed to increased CVT HIV target cell abundance. Flow cytometry also revealed that individuals with BV had an increased frequency of dysfunctional CX and VT CD39+ Tconv and CX tissue-resident CD69+CD103+ Tconv cells, reported to be implicated in HIV acquisition risk and replication. Many soluble immune factor differences in the CVT further support that BV elicits diverse and complex CVT immune alterations.CONCLUSIONOur comprehensive analysis expands on potential immunological mechanisms that may underlie the adverse health outcomes associated with BV, including increased HIV susceptibility.TRIAL REGISTRATIONClinicalTrials.gov NCT03701802.FUNDINGThis work was supported by National Institutes of Health grants R01AI131914, R01AI141435, and R01AI129715.
Sexual behaviour of heterosexual men and women receiving antiretroviral pre-exposure prophylaxis for HIV prevention: a longitudinal analysis
Scarce data are available to assess sexual behaviour of individuals using antiretroviral pre-exposure prophylaxis for HIV prevention. Increased sexual risk taking by individuals using effective HIV prevention strategies, like pre-exposure prophylaxis, could offset the benefits of HIV prevention. We studied whether the use of pre-exposure prophylaxis in HIV-uninfected men and women in HIV-serodiscordant couples was associated with increased sexual risk behaviour. We undertook a longitudinal analysis of data from the Partners PrEP Study, a double-blind, randomised, placebo-controlled trial of daily oral pre-exposure prophylaxis among HIV-uninfected partners of heterosexual HIV-serodiscordant couples (n=3163, ≥18 years of age). Efficacy for HIV prevention was publicly reported in July 2011, and participants continued monthly follow-up thereafter. We used regression analyses to compare the frequency of sex—unprotected by a condom—during the 12 months after compared with the 12 months before July 2011, to assess whether knowledge of pre-exposure prophylaxis efficacy for HIV prevention caused increased sexual risk behaviour. We analysed 56 132 person-months from 3024 HIV-uninfected individuals (64% male). The average frequency of unprotected sex with the HIV-infected study partner was 59 per 100 person-months before unmasking versus 53 after unmasking; we recorded no immediate change (p=0·66) or change over time (p=0·25) after July, 2011. We identified a significant increase in unprotected sex with outside partners after July, 2011, but the effect was small (average of 6·8 unprotected sex acts per year vs 6·2 acts in a predicted counterfactual scenario had patients remained masked, p=0·04). Compared with before July, 2011, we noted no significant increase in incident sexually transmitted infections or pregnancy after July, 2011. Pre-exposure prophylaxis, provided as part of a comprehensive prevention package, might not result in substantial changes in risk-taking sexual behaviour by heterosexual couples. The Bill & Melinda Gates Foundation and the US National Institute of Mental Health.
Single-agent tenofovir versus combination emtricitabine plus tenofovir for pre-exposure prophylaxis for HIV-1 acquisition: an update of data from a randomised, double-blind, phase 3 trial
Antiretroviral pre-exposure prophylaxis (PrEP), with daily oral tenofovir disoproxil fumarate or tenofovir disoproxil fumarate in combination with emtricitabine, has been shown to be efficacious for HIV-1 prevention. Although the use of more than one antiretroviral agent is essential for effective HIV-1 treatment, more than one agent might not be required for effective prophylaxis. We assessed the efficacy of single-agent tenofovir disoproxil fumarate relative to combination emtricitabine plus tenofovir disoproxil fumarate as PrEP. We did a randomised, double-blind, placebo-controlled three-group phase 3 trial of daily oral tenofovir disoproxil fumarate and emtricitabine plus tenofovir disoproxil fumarate PrEP in HIV-1 uninfected individuals in heterosexual HIV-1 serodiscordant couples from Kenya and Uganda. After an interim review, the trial's placebo group was discontinued and thereafter the active groups were continued, and participants initially randomly assigned to placebo were offered rerandomisation in a 1:1 ratio to tenofovir disoproxil fumarate or emtricitabine plus tenofovir disoproxil fumarate as PrEP. The primary endpoints were HIV-1 seroconversion and safety. This trial is registered with ClinicalTrials.gov, number NCT00557245. 4410 (99·6%) of 4427 couples received tenofovir disoproxil fumarate or emtricitabine plus tenofovir disoproxil fumarate and were followed up for HIV-1 acquisition. Of 52 incident HIV-1 infections, 31 occurred in individuals assigned tenofovir disoproxil fumarate (incidence 0·71 cases per 100 person-years) and 21 were in those assigned emtricitabine plus tenofovir disoproxil fumarate (0·48 cases per 100 person-years); HIV-1 incidence in the placebo group until discontinuation was two cases per 100 person-years. HIV-1 prevention efficacy with emtricitabine plus tenofovir disoproxil fumarate was not significantly different from that of tenofovir disoproxil fumarate alone (hazard ratio [HR] 0·67, 95% CI 0·39–1·17; p=0·16). Detection of tenofovir in plasma samples, compared with no detection and as measured in seroconverters and a subset of non-seroconverters, was associated with an 85% relative risk reduction in HIV-1 acquisition for the tenofovir disoproxil fumarate group (HR 0·15, 95% CI 0·06–0·37; p<0·0001) and 93% for the emtricitabine plus tenofovir disoproxil fumarate group (0·07, 0·02–0·23; p<0·0001). No significant differences were noted in the frequency of deaths, serious adverse events, or serum creatinine and phosphorus abnormalities between the two groups. These results do not rule out the potential for a slight difference in HIV-1 protection with tenofovir disoproxil fumarate compared with emtricitabine plus tenofovir disoproxil fumarate, but show that once-daily oral tenofovir disoproxil fumarate or emtricitabine plus tenofovir disoproxil fumarate regimens both provide high protection against HIV-1 acquisition in heterosexual men and women. Bill & Melinda Gates Foundation and US National Institutes of Health.
Feasibility of self-testing for acute malaria using rapid diagnostic tests in three peri-urban sub-Saharan African community settings
Background Malaria is a significant cause of under-five child mortality in sub-Saharan Africa (SSA). The World Health Organization (WHO)-approved rapid diagnostic tests (RDT) for malaria offer a resource-efficient alternative to gold-standard diagnostic methods and may improve timely access to care through self-testing. Methods The feasibility of use of RDT for self-testing was evaluated in 100 households each in Migori County, Kenya; KwaZulu-Natal Province, South Africa; and Copperbelt Province, Zambia. Surveys assessed perceived usability, acceptability, and preferences for RDTs among consenting participants. Results Among 225 participants in Kenya, 80 in South Africa, and 163 in Zambia, 25 (11.5%), 0 (0.0%), and 3 (1.8%) tested positive for malaria, respectively. In Kenya and Zambia, 89% of participants reported previous malaria diagnoses. Participants across all three sites interpreted the RDT with 100% sensitivity and 99.7% specificity compared to RDT interpretation performed by a trained study team member, with only one individual interpreting their test incorrectly. Over 96% of participants across all three sites felt the RDT would be easy to use for specimen collection, test operation, and result interpretation, and 160 (100%) Kenyan participants, 74 (96.1%) South African participants, and 157 (99.4%) Zambian participants felt confident that they had interpreted their own test correctly. Participants’ perceived comfort for future self-testing with an RDT was high in Kenya (92%) and Zambia (86%), and moderate in South Africa (66%). Conclusions These findings indicate that RDT self-testing is highly acceptable and feasible in SSA settings with a high malaria burden.
ThiPhiSA: new pathways to TB prevention from community screening – a household-randomised controlled trial in KwaZulu-Natal, South Africa
IntroductionTuberculosis (TB) remains the leading cause of infectious disease deaths, particularly among people living with HIV (PWH). Despite being preventable, TB preventive therapy (TPT) uptake is low in high-burden regions like South Africa, where new guidelines have expanded TPT eligibility and introduced shorter, more effective regimens like 3 months of weekly rifapentine and isoniazid (3HP). As differentiated service delivery models for HIV care have proven effective, there is increasing recognition that decentralising TPT delivery may improve coverage and completion. This study explores whether a community-based TPT delivery strategy can enhance uptake and completion of TPT compared with traditional clinic-based services.Method and analysisWe will conduct a household-randomised, non-blinded, controlled trial. Persons eligible for TPT will be recruited from the TB TRIAGE+Trial study, a community-based household TB screening study. Households containing at least one person eligible for TPT will be randomised 1:1 to either community-based TPT or standard-of-care clinic referral for TPT. At enrolment, all participants will be provided with a 2-week supply of TPT in the community. Participants randomised to the community arm will receive the entire course of TPT in a single dispense (12 weeks of 3HP or 6 months of isoniazid, if 3HP is contraindicated). Clinic-arm participants will be referred to their local clinic for the remainder of their course of TPT and will collect TPT refills on the clinic-determined schedule. Our primary outcome is the proportion of participants who complete a course of TPT. Secondary outcomes include overall adherence to TPT, predictors of adherence with TPT, participant satisfaction with the assigned TPT delivery method and adverse events.Ethics and disseminationThe study and its tools were approved by the Human Sciences Research Councils Research Ethics Committee (approval number: 2/25/10/23), based in Pretoria, Gauteng, South Africa, as well as the University of Washington Institutional Review Board (Study 00018448). Study findings will be shared through the community advisory group and local stakeholder meetings, relevant international and local meetings/conferences and peer-reviewed publications.Trial registration numberNCT06214910. Date and version: 3.0, 30 July 2024.