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Background HIV-1 incidence calculation currently includes recency classification by HIV-1 incidence assay and unsuppressed viral load (VL ≥ 1000 copies/mL) in a recent infection testing algorithm (RITA). However, persons with recent classification not virally suppressed and taking antiretroviral (ARV) medication may be misclassified. Setting We used data from 13 African household surveys to describe the impact of an ARV-adjusted RITA on HIV-1 incidence estimates. Methods HIV-seropositive samples were tested for recency using the HIV-1 Limiting Antigen (LAg)-Avidity enzyme immunoassay, HIV-1 viral load, ARVs used in each country, and ARV drug resistance. LAg-recent result was defined as normalized optical density values ≤1.5. We compared HIV-1 incidence estimates using 2 RITA: RITA1: LAg-recent + VL ≥ 1000 copies/mL and RITA2: RITA1 + undetectable ARV. We explored RITA2 with self-reported ARV use and with clinical history. Results Overall, 357 adult HIV-positive participants were classified as having recent infection with RITA1. RITA2 reclassified 55 (15.4%) persons with detectable ARV as having long-term infection. Those with detectable ARV were significantly more likely to be aware of their HIV-positive status (84% vs. 10%) and had higher levels of drug resistance (74% vs. 26%) than those without detectable ARV. RITA2 incidence was lower than RITA1 incidence (range, 0%-30% decrease), resulting in decreased estimated new infections from 390,000 to 341,000 across the 13 countries. Incidence estimates were similar using detectable or self-reported ARV (R2 > 0.995). Conclusions Including ARV in RITA2 improved the accuracy of HIV-1 incidence estimates by removing participants with likely long-term HIV infection.

BACKGROUND Measurement of mother-to-child HIV transmission through population-based surveys requires large sample sizes because of low HIV prevalence among children. We estimate potential improvements in sampling efficiency resulting from a targeted sample design. SETTING Eight countries in sub-Saharan Africa with completed Population-based HIV Impact Assessment (PHIA) surveys as of 2017. METHODS The PHIA surveys used a geographically stratified 2-stage sample design with households sampled from randomly selected census enumeration areas. Children (0-14 years of age) were eligible for HIV testing within a random subsample of households (usually 50%). Estimates of child HIV prevalence in each country were calculated using jackknife replicate weights. We compared sample sizes and precision achieved using this design with a 2-phase disproportionate sample design applied to strata defined by maternal HIV status and mortality. RESULTS HIV prevalence among children ranged from 0.4% (95% confidence interval: 0.2 to 0.6) in Tanzania to 2.8% (95% confidence interval: 2.2 to 3.4) in Eswatini with achieved relative standard errors between 11% and 21%. The expected precision improved in the targeted design in all countries included in the analysis, with proportionate reductions in mean squared error ranging from 27% in Eswatini to 61% in Tanzania, assuming an equal sample size. CONCLUSIONS Population-based surveys of adult HIV prevalence that also measure child HIV prevalence should consider targeted sampling of children to reduce required sample size, increase precision, and increase the number of positive children tested. The findings from the PHIA surveys can be used as baseline data for informing future sample designs.

BACKGROUND The need for accurate HIV annual program planning data motivated the compressed timeline for the 2018 Nigerian HIV/AIDS Indicator and Impact Survey (NAIIS). The survey team used stakeholder cooperation and responsive design, using survey process and paradata to refine survey implementation, to quickly collect high-quality data. We describe processes that led to generation of data for program and funding decisions, ensuring HIV services were funded in 2019. SETTING Nigeria is the most populous country in Africa, with approximately 195 million people in 36 states and the Federal Capital Territory. Challenges include multiple security threats, poor infrastructure, seasonal rains, and varied health system capacity. METHODS Stakeholders worked together to plan and implement NAIIS. Methods from other population-based HIV impact assessments were modified to meet challenges and the compressed timeline. Data collection was conducted in 6 webs. Responsive design included reviewing survey monitoring paradata and laboratory performance. Costs required to correct data errors, for example, staff time and transportation, were tracked. RESULTS NAIIS data collection was completed in 23 weeks, ahead of the originally scheduled 24 weeks. Responsive design identified and resolved approximately 68,000 interview errors, affecting approximately 62,000 households, saving about US$4.4 million in costs. Biweekly field laboratory test quality control improved from 50% to 100% throughout NAIIS. CONCLUSIONS Cooperation across stakeholders and responsive design ensured timely release of NAIIS results and informed planning for HIV epidemic control in Nigeria. Based on NAIIS results, funds were provided to place an additional 500,000 HIV-positive Nigerians on antiretroviral therapy by the end of 2020, pushing Nigeria toward epidemic control.