Estimating HIV incidence, prevalence, and percent of undiagnosed infections in Taiwan using CD4 data.

BACKGROUND/PURPOSE:Estimation of the human immunodeficiency virus (HIV) epidemic trend and percent of undiagnosed infections is an important measure for the assessment of HIV control programs. In this study, we aimed to investigate and estimate the HIV incidence, HIV prevalence, and percent of undiagnosed HIV infections in Taiwan using the CD4 depletion model. METHODS:Data on newly reported HIV diagnoses during 2012-2019 were obtained from the National HIV/AIDS reporting and case management system. We used an Asian-adjusted CD4 depletion model to determine diagnosis delays and then used this distribution and HIV case surveillance data to estimate the incidence, prevalence and percent of undiagnosed infections. RESULTS:The estimated HIV incidence rate decreased after 2012, from 9.4 per 100,000 people (95% confidence interval [CI]: 8.7 to 10.2) to 7.1 per 100,000 people (95% CI: 5.7 to 8.5) in 2019. The prevalence rate increased from 111 per 100,000 people (95% CI: 107 to 116) in 2012 to 158 per 100,000 people (95% CI: 146 to 169) in 2019, whereas the undiagnosed rate decreased from 21.5% (95% CI: 18.2%-24.8%) in 2012 to 12.1% (95% CI: 8.9%-15.2%) in 2019. In addition, the undiagnosed percentage in the population of men who have sex with men (MSM) also decreased from 28.8% to 13.6% during this period. CONCLUSION:We found decreases in the HIV incidence and undiagnosed percentage from 2012 to 2019 in Taiwan. These findings highlight the importance of intensified HIV testing efforts to achieve the global 95-95-95 goals by 2030.