Voucher incentives to improve viral suppression among HIV-positive people who inject drugs and men who have sex with men in India: a cluster randomised trial.

BACKGROUND: Progress on HIV treatment outcomes for people who inject drugs and men who have sex with men in India has been slow compared with that in other populations. We assessed whether HIV treatment incentives would improve outcomes among these groups. METHODS: We did a matched-pair, cluster randomised trial in 16 sites (eight for people who inject drugs and eight for men who have sex with men) across 15 cities in India. We recruited cohorts of HIV-positive people who inject drugs or men who have sex with men who were antiretroviral therapy (ART)-naive or had less than 12 months of ART exposure. We randomised sites to provide incentives or usual care. At intervention sites, we provided incentive vouchers, which could be exchanged for food or household goods, for attending motivational interviewing sessions and timely appointments at government ART clinics. An ART-naive participant meeting all targets could earn the equivalent to 14 days' wages over 12 months. The primary outcome was survival with viral suppression at 12 months. We used an intention-to-treat analytic approach appropriate for matched-pair cluster randomised trials, adjusting for baseline viral suppression. This study was registered with ClinicalTrials.gov, NCT02969915, and is complete. FINDINGS: Between Oct 30, 2017, and Oct 12, 2018, we recruited 1200 people who inject drugs and 1114 men who have sex with men living with HIV. Among people who inject drugs, 154 (12·8%) identified as female gender and 1046 (87·2%) as male. The site median percentage of participants earning one or more incentives was 96·1% (IQR 93·7-98·1). At 12 months, HIV viral suppression was 31·9% (n=383) among people who inject drugs and 52·1% (n=580) among men who have sex with men. The incentive intervention was not associated with significantly improved survival with viral suppression compared with usual care (adjusted prevalence difference 9·6 percentage points, 95% CI -4·4 to 23·7). INTERPRETATION: Despite high intervention engagement, incentives did not improve survival with viral suppression among people who inject drugs and men who have sex with men living with HIV in India. The poor outcomes overall underscore the need for innovative, multilevel approaches to engage marginalised people living with HIV in low-income and middle-income settings. FUNDING: US National Institutes of Health, Elton John AIDS Foundation.

A Mixture Model for Estimating SARS-CoV-2 Seroprevalence in Chennai, India.

Serological assays used to estimate the prevalence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) often rely on manufacturers' cutoffs established on the basis of severe cases. We conducted a household-based serosurvey of 4,677 individuals in Chennai, India, from January to May 2021. Samples were tested for SARS-CoV-2 immunoglobulin G (IgG) antibodies to the spike (S) and nucleocapsid (N) proteins. We calculated seroprevalence, defining seropositivity using manufacturer cutoffs and using a mixture model based on measured IgG level. Using manufacturer cutoffs, there was a 5-fold difference in seroprevalence estimated by each assay. This difference was largely reconciled using the mixture model, with estimated anti-S and anti-N IgG seroprevalence of 64.9% (95% credible interval (CrI): 63.8, 66.0) and 51.5% (95% CrI: 50.2, 52.9), respectively. Age and socioeconomic factors showed inconsistent relationships with anti-S and anti-N IgG seropositivity using manufacturer cutoffs. In the mixture model, age was not associated with seropositivity, and improved household ventilation was associated with lower seropositivity odds. With global vaccine scale-up, the utility of the more stable anti-S IgG assay may be limited due to the inclusion of the S protein in several vaccines. Estimates of SARS-CoV-2 seroprevalence using alternative targets must consider heterogeneity in seroresponse to ensure that seroprevalence is not underestimated and correlates are not misinterpreted.