Fig. 4

Test-and-treat could increase HIV prevalence. a, c The rate of change in HIV incidence, (b, d) the proportion of the PLWHA (people living with HIV/AIDS). Without test-and-treat policy, the rate of diagnosis was set as α = 0. Under the test-and-treat policy, α = 0.3 was adopted. Parameter values are μ = 1/60, ρ = 1/10, γ = 1/3, β = 0.15, δ = 1/2 and ε = 0.3. The test-and-treat reduces both the incidence and the prevalence in (a) and (b). For panel (c) and (d), ε = 0.5 was used instead of ε = 0.3 as the relative transmissibility for those who are diagnosed. In this scenario, test-and-treat increases HIV prevalence. Initial values are H _u  = 0.15, A _u  = 0.01, H _d  = 0 and A _d  = 0