Mathematical analysis of an HIV model with impulsive antiretroviral drug doses

In this paper, we incorporate the periodic therapy from antiretroviral drugs for HIV into the standard within‐host virus model, and study the stability and bifurcation of the system. It is shown that when the basic reproduction number of virus is less than one, there is an infection‐free equilibrium which is globally stable. Further, if it is greater than one, the HIV infection is uniformly persistent. Besides, subharmonic bifurcation occurs under suitable conditions, and chaotic attractor may emerge through period doubling routes, which can be used to explain the HIV patients’ unpredictable unstable health states, even after a long and hard treatment.