A control systems analysis of HIV prevention model using impulsive input

The effects of a training program for reducing nurses' discrimination towards PLWHAs

Performing a training program for reducing nurses' discrimination towards AIDS clients, and then evaluating the effect of the training model and analyzing the influencing factors of the training effect to form a long-run training model. 150 clinical nurses were selected to attend the program to reduce nurses' discrimination towards AIDS clients. The program included 3 steps: knowledge education, psychological intervention, and behavior correcting. Before the program, we conducted pre-research to learn the current situation, including existing discrimination and training needs. Selected nurses were asked to complete questionnaires before and 6 months after training, and the trainees were from several hospitals in Haikou. The research period was from March to September 2020. The scores for AIDS-related knowledge, discrimination attitudes, and nursing standard behavior before training were (49.69 ± 3.80), (47.01 ± 3.70), and (35.98 ± 3.01), respectively, and the scores from 6 months after training were (59.01 ± 3.88), (52.19 ± 4.98), and (38.12 ± 2.98), respectively. Correlation analysis revealed that the scores for the nurses' AIDS-related knowledge and behavior were positively correlated (R = 0.31, P < .05); however, there was no correlation found between attitude and behavior (P > .05); no significant differences were observed in the 3 scores among nurses in different departments and nurses with different working durations. There was a significant difference detected among nurses in their experience caring for AIDS clients (F = 3.80, P < .05). The nurses with higher education levels also showed a significant difference compared to those with low education levels on their knowledge and behavior scores ([F = 3.49, P < .05] and [F = 4.68, P < .05], respectively). AIDS-related knowledge training and psychological intervention can effectively reduce the discriminatory attitudes of nurses towards AIDS clients.

From the hospital scale to nationwide: observability and identification of models for the COVID-19 epidemic waves

Two mathematical models of the COVID-19 dynamics are considered as the health system in some country consists in a network of regional hospital centers. The first macroscopic model for the virus dynamics at the level of the general population of the country is derived from a standard SIR model. The second local model refers to a single node of the health system network, i.e. it models the flows of patients with a smaller granularity at the level of a regional hospital care center for COVID-19 infected patients. Daily (low cost) data are easily collected at this level, and are worked out for a fast evaluation of the local health status thanks to control systems methods. Precisely, the identifiability of the parameters of the hospital model is proven and thanks to the availability of clinical data, essential characteristics of the local health status are identified. Those parameters are meaningful not only to alert on some increase of the infection, but also to assess the efficiency of the therapy and health policy.

Robust control of HIV infection by antiretroviral therapy: a super-twisting sliding mode control approach

Acquired immune deficiency syndrome is an epidemic infectious disease which is caused by the human immunodeficiency virus (HIV) and that has proliferated across worldwide. It has been a matter of concern for the scientific community to develop an antiretroviral therapy, which will prompt a rapid decline in viral abundance. With this motivation, this study proposes the design of a robust super twisting sliding mode controller based on output information for an uncertain HIV infection model. The control objective is to decrease the concentration of infected CD4+ T cells to a specified level by drug administration using only the output information of the uncertain HIV infection model which is total CD4+ T cell concentration. The robust output-feedback controller has been developed in combination with a robust exact differentiator, functioning as an observer. The reported analysis demonstrates that the approach proposed here is capable of ensuring robust performance under several operating conditions, measurement and modelling error, parametric uncertainties and external disturbances and the simulation results prove the proficiency of the controller proposed.

Occurrence of HIV eradication for preexposure prophylaxis treatment with a deterministic HIV model

The authors examine the human immunodeficiency virus (HIV) eradication in this study using a mathematical model and analyse the occurrence of virus eradication during the early stage of infection. To this end they use a deterministic HIV-infection model, modify it to describe the pharmacological dynamics of antiretroviral HIV drugs, and consider the clinical experimental results of preexposure prophylaxis HIV treatment. They also use numerical simulation to model the experimental scenario, thereby supporting the clinical results with a model-based explanation. The study results indicate that the protocol employed in the experiment can eradicate HIV in infected patients at the early stage of the infection.

Analysis of the HIV eradication phenomenon at the early stage of infection with an extracellular deterministic model

We investigate the phenomenon of HIV eradication at the early stage of the infection and evaluate the chance of the eradication with a mathematical model. We employ an extracellular deterministic model of the HIV infection dynamics and modify the model to include the pharmacokinetics and pharmacodynamics of antiretroviral HIV drugs. In addition we consider clinical experiments for the prevention of HIV infection using pre-exposure chemoprophylaxis treatment. Exploiting the mathematical model we implement the experiment numerically. The study in this paper is supported by the clinical results and provides a theoretical explanation for the results. The result suggests that the protocol of the experiment eradicates the virus in HIV infected patients.