Impact of Public Policies AImed at Improving Hiv Care and Surveillance in Brazil: A Bayesian Time Series Analysis Approach

HIV infection remains a global challenge, with 1.3 million new cases reported in 2023. In Brazil, until 2013, there was significant underreporting, as mandatory notification was limited to specific populations. In 2014, a reform in public health policies established universal mandatory notification of HIV, accompanied by advances in diagnosis and treatment, such as the publication of a new technical diagnostic manual and the adoption of the “Test and Treat” strategy, which recommends early initiation of antiretroviral therapy. To evaluate the impact of public health policies targeting HIV implemented in Brazil in 2014, focusing on epidemiological surveillance, case detection, and AIDS-related mortality outcomes. A national epidemiological study analyzing 1,198,895 reported cases of HIV/AIDS between 2007 and 2022, using Bayesian structural time-series modeling (BSTS) to estimate the impact of the 2014 intervention on the incidence of HIV and AIDS notifications among adults, children, pregnant women, and puerperae, as well as on AIDS-related deaths in adults. The model was developed using the CausalImpact package (v1.3.0) in R, with 25,000 Markov Chain Monte Carlo simulations and Gibbs sampling. Spearman correlation was used to assess the association between ART coverage and AIDS-related mortality. Regional variations were explored using synthetic controls representing populations not directly affected by the mandatory notification policy. The policy reform resulted in a 589% increase in adult notification incidence, 480% among women and 660% among men. The largest increases were observed in the South (1,310%), North (1,160%), and Northeast (1,010%) regions, with smaller increases in the Center-West (460%) and Southeast (330%). A mean 21% reduction in AIDS-related deaths was observed, showing a strong negative correlation with ART coverage (ρ = –0.93; p < 0.001). The implementation of mandatory notification, combined with targeted diagnostic and therapeutic strategies, strengthened HIV care systems by promoting early diagnosis and treatment and preventing disease progression among people living with HIV. The study demonstrated significant improvements in surveillance and HIV/AIDS outcomes in Brazil, providing evidence to reinforce public health policies and guide global epidemic-control strategies.