Background: Based on modeled estimates, 13% of people in Zambia were living with HIV in 2014. The 2016 Zambia Population-based HIV Impact Assessment (ZAMPHIA) is the first national survey to directly assess the status of Zambia''s HIV epidemic by measuring HIV incidence. Findings from ZAMPHIA and progress toward meeting the UNAIDS 90-90-90 targets, including viral load suppression (VLS), are presented.
Methods: A nationally representative household-based sample of 12,310 eligible households was selected in 511 enumeration areas; analyses account for study design. Consenting participants provided demographic and clinical information and blood samples for household HIV testing per national guidelines. HIV-seropositive results were confirmed using the Geenius supplemental assay; viral load and limiting antigen (LAg) avidity EIA testing were performed at a central lab on all HIV-seropositive samples. HIV incidence estimates were based on World Health Organization criteria for recent infection (LAg < 1.5 OD units and HIV RNA > 1000 c/ml). VLS was defined as HIV RNA < 1000 c/ml.
Results: In total, 19,029 adults and 7,959 children provided interviews and blood samples (response rate: 68%). Participation by eligible adults was higher for women than men (71% vs 63%, P< 0.0001). HIV prevalence estimates among adults aged 15-59 and children aged 0-14 were 12.3% and 1.3%, respectively. Adult HIV incidence was 0.66% (female 1.00%, male 0.33%); mean VLS prevalence among all HIV-seropositive adults was 59.8%. An estimated 67.3% of persons living with HIV (PLHIV) knew their HIV status (1st 90), 85.4% of PLHIV who reported knowing their status also reported receiving ART (2nd 90), and 89.2% of these PLHIV who reported receiving ART were virally suppressed (3rd 90).
Conclusions: Zambia has achieved progress towards meeting the UNAIDS 90-90-90 goals. HIV prevalence is stabilizing; HIV incidence is low; and prevalence of VLS is high. Identification of gaps in testing, ART, and viral load suppression is needed to better target expansion of HIV treatment services in Zambia.

HIV prevalence among adults, % [95% CI]9.5 [8.8, 10.3]14.9 [14.0, 15.8]12.3 [11.6, 12.9]
HIV prevalence among children, % [95% CI]----1.3 [1.0, 1.6]
HIV incidence among adults % [95% CI]0.33 [0.11, 0.56]1.00 [0.65, 1.36]0.66 [0.45, 0.88]
Viral load suppression (VLS) prevalence among HIV+ adults, % [95% CI]57.4 [53.4, 61.5]61.3 [58.7, 63.8]59.8 [57.4, 62.2]
Prevalence of HIV+ adults who report knowing their HIV status, % [95% CI]62.8 [58.7, 66.8]70.0 [67.5, 72.5]67.3 [64.8, 69.7]
Self-reported ART prevalence among HIV+ adults who report knowing their HIV status, % [95% CI]86.2 [83.1, 89.4]84.9 [82.5,87.4]85.4 [83.4, 87.4]
VLS prevalence among HIV+ adults who report ART and knowing their HIV status, % [95% CI]88.2 [85.1, 91.4]89.7 [87.7, 91.8]89.2 [87.4, 91.0]
[Selected Findings from 2016 ZAMPHIA]