The Effectiveness of the UNAIDS Strategy«90-90-90»in Populations with Different Population Growth

Abstract

Introduction. Available data indicate that the effectiveness of the strategy of "90-90-90" varies considerably between countries. For example, Australia with figures 90-90-79 (2016) has not achieved the negative trend of the incidence and prevalence, while Niger 35-90-57 performance demonstrates a stable decrease in the HIV epidemic. One possible explanation for the observed processes may have different development of the epidemic process in populations that differ by demographic characteristics. From this we can assume that the epidemic control in a strategy of «90-90-90» or any other strategies will differ significantly in such self-regulating systems.Aim: modeling the dynamics of the epidemic process in populations with different probability of HIV transmission and negative, zero, positive population growth.Materials and methods: Computer probabilistic modeling by the Monte Carlo method was carried out. The following parameters were used to describe the epidemic process: population size, birth rate, mortality, HIV prevalence, lethality among patients with HIV/AIDS and probability of HIV transmission. The values of these parameters were close to the UNAIDS global statistics. It is assumed that the effective management of the epidemic reduce the probability of HIV transmission in the population. The dynamics of the population size, incidence and prevalence of HIV infection in populations with negative, zero, positive natural growth and the probability of HIV transmission in the population from 50% to 10% has been consistently studied. Statistical processing carried out by the Student method.Results and discussion. In populations with a negative population growth and a probability of HIV transmission of 0.5, incidence and prevalence at the initial stage are characterized by an increasing trend, reach peak values and decrease to zero. When reducing the probability of HIV transmission peak becomes plateau or directly take the downward shape. In general terms, similar patterns are recorded at zero population growth. The incidence and prevalence of HIV infection with a positive population growth are changing cyclically up and down. Change transmission probabilities range from 0.5 to 0.2 is characterized by a decrease in the frequency and amplitude of peaks increasing incidence and prevalence. When transmission probabilities at 0.1 epidemic process drops sharply. According to the simulation, any managerial impact in countries with negative population growth should be effective. Practical evidence does not contradict theory. For example, indicators "56-66-59" in Ukraine led to a decrease in the incidence. Management actions in populations with positive population growth that reduce the probability of HIV transmission by 20% or 40% are ineffective. When reaching 80%, the epidemic process abruptly stops.Conclusions. The effect of reducing the probability of HIV transmission in populations with a negative and zero population growth is expressed as a linear reduction in incidence and prevalence (at fixed lethality). In populations with a positive natural growth reduction transmission probabilities less than 40% strategically not effective, and when it reaches 80% potentiated abrupt cessation epidemic process.

Keywords

• hiv infection
• mathematical model
• hiv transmission
• stochastic process
• epidemiological factors
• epidemiological studies