Naomi: a new modelling tool for estimating HIV epidemic indicators at the district level in sub-Saharan Africa.

INTRODUCTION: HIV planning requires granular estimates for the number of people living with HIV (PLHIV), antiretroviral treatment (ART) coverage and unmet need, and new HIV infections by district, or equivalent subnational administrative level. We developed a Bayesian small-area estimation model, called Naomi, to estimate these quantities stratified by subnational administrative units, sex, and five-year age groups. METHODS: Small-area regressions for HIV prevalence, ART coverage and HIV incidence were jointly calibrated using subnational household survey data on all three indicators, routine antenatal service delivery data on HIV prevalence and ART coverage among pregnant women, and service delivery data on the number of PLHIV receiving ART. Incidence was modelled by district-level HIV prevalence and ART coverage. Model outputs of counts and rates for each indicator were aggregated to multiple geographic and demographic stratifications of interest. The model was estimated in an empirical Bayes framework, furnishing probabilistic uncertainty ranges for all output indicators. Example results were presented using data from Malawi during 2016-2018. RESULTS: Adult HIV prevalence in September 2018 ranged from 3.2% to 17.1% across Malawi's districts and was higher in southern districts and in metropolitan areas. ART coverage was more homogenous, ranging from 75% to 82%. The largest number of PLHIV was among ages 35 to 39 for both women and men, while the most untreated PLHIV were among ages 25 to 29 for women and 30 to 34 for men. Relative uncertainty was larger for the untreated PLHIV than the number on ART or total PLHIV. Among clients receiving ART at facilities in Lilongwe city, an estimated 71% (95% CI, 61% to 79%) resided in Lilongwe city, 20% (14% to 27%) in Lilongwe district outside the metropolis, and 9% (6% to 12%) in neighbouring Dowa district. Thirty-eight percent (26% to 50%) of Lilongwe rural residents and 39% (27% to 50%) of Dowa residents received treatment at facilities in Lilongwe city. CONCLUSIONS: The Naomi model synthesizes multiple subnational data sources to furnish estimates of key indicators for HIV programme planning, resource allocation, and target setting. Further model development to meet evolving HIV policy priorities and programme need should be accompanied by continued strengthening and understanding of routine health system data

HIV suppression was maintained during the COVID-19 pandemic in Malawi: a program-level cohort study.

OBJECTIVE Measures introduced to reduce the spread of SARS-CoV-2 by the Malawi government and the national HIV care program might have compromised treatment outcomes of patients living with HIV on antiretroviral therapy (ART). We studied viral load (VL) outcomes before and during the COVID-19 epidemic in Malawi. STUDY DESIGN AND SETTING In this population-based cohort study, we included all routine VL measurements collected from July 2019 to December 2020 in about 650 ART clinics in Malawi. We examined differences between pandemic periods (before/during COVID-19) for i) VL monitoring and ii) VL suppression (VLS: <1000 copies/ml). For i) we studied the number of VL measurements over time and assessed predictors of missed measurements before and during COVID-19 in logistic regression models. For ii) we estimated the odds of VLS before and during the COVID-19 epidemic stratified by treatment regimen using generalized estimation equations adjusted for age, sex, time on ART, and type of biological sample. We imputed missing treatment regimens by population-calibrated multiple imputation. RESULTS We included 607,894 routine VL samples from 556,281 patients. VL testing declined during COVID-19 (243,729; 40%) compared to before COVID-19 (365,265; 60%), but predictors of missing tests were similar in the two periods. VLS rates increased slightly from 93% before to 94% during COVID-19. Compared to before COVID-19, the odds of VLS increased during COVID-19 for patients on protease inhibitor-based (PI) regimens (adjusted odds ratio [aOR] 1.22, 95% CI: 0.99-1.49) and for patients on integrase strand transfer inhibitor-based (INSTI) regimens (aOR 1.10, 95% CI: 1.03-1.17). There was no difference in VLS between the two periods among patients on non-nucleoside reverse transcriptase inhibitor-based (NNRTI) regimens. VLS varied by age, sex, regimen, and duration on ART, ranging from 45.1% (95% CI 40.3-50.0%) to 97.2% (95% CI 96.9-97.4%). CONCLUSION There was a significant decline in VL monitoring during COVID-19, but we did not find clear evidence that the pandemic reduced VL suppression rates. Routine scheduled VL monitoring, targeted adherence support, and timely regimen switches for patients with treatment failure remain critical to improving VLS

Factors associated with HIV viral suppression among children and adults receiving antiretroviral therapy in Malawi in 2021: Evidence from the Laboratory Management Information System.

OBJECTIVE To describe the prevalence of HIV viral suppression and assess the factors associated with HIV viral suppression among persons receiving ART in Malawi in 2021. METHODS Implementation study using routinely collected patient-level HIV RNA-PCR test result data extracted from the national Laboratory Management Information System (LIMS) database managed by the Department of HIV/AIDS in 2021. We calculated frequencies, proportions and odds ratios (OR) of HIV viral suppression with their associated 95% confidence intervals (95%CI). We performed a random-effects logistic regression to determine the risk factors associated with HIV viral suppression amongst ART patients, controlling for the spatial autocorrelation between districts and adjusting for other variables. RESULTS We evaluated 515,797 adults and children receiving ART and having a viral load test in 2021. Of these, 92.8% had HIV viral suppression. ART patients living in urban areas had lower likelihood of HIV viral suppression than those living in rural areas (adjusted OR [aOR]=0.95, 95%CI: 0.92-0.99, P=0.01). There was an increasing trend in HIV viral suppression with increasing ART duration. Routine VL monitoring samples were 39% more likely to have suppressed VL values than confirmatory HIV VL monitoring samples (aOR=1.39; 95%CI:1.34-1.43, P<0.001). CONCLUSION This is the first national analysis of Malawi HIV VL data from LIMS. Our findings show the need to particularly consider the urban residents, those below 20 years, males, those on ART for less than a year as well as those on specific ARV regimens in order to persistently suppress HIV VL and consequently achieve the goal of achieving HIV VL suppression by 2030