Control of the HIV infection and drug dosage

An increasing number of sophisticated control algorithms become available in the current literature to optimize the HIV therapy. Unfortunately, the pharmacokinetics and pharmacodynamics of antiretroviral drugs are ignored and these algorithms remain purely theoretic. This issue is investigated explicitly in this paper. An elementary pharmacodynamics model is combined with a non linear feedback control computed from standard engineering methods. It is shown that it results in the design of a realistic dosage regimen which drives the immunological system close to the healthy equilibrium state. Although the problem is dealt as a single input system, it is argued that the procedure can be extended to a multitherapy design or to any available control law.     

Occupational HIV infection. Medical workers and HIV prevention

The analysis of the possibility of suffering injuries at a work place, their causes, the knowledge of HIV infection, attitude towards the infected person is presented. The work was carried out, starting from 1990. Every 2 years the anonymous questioning of members of the medical personnel of different specialties at medical institutions of different profile and level was carried out. Five questionings on injuries suffered during work, the knowledge of HIV infection and the attitude of members of the medical profession towards HIV-positive persons. In most cases injuries are inflicted by injection needles (79%), during operations (12%), by splinters of broken medical glassware and appliances (3%) and in other cases (6%). In 91% of cases injuries caused by needles occur in the process of placing caps on the needles. In the course of 9 years changes in the level of knowledge and the attitude towards HIV-infected persons occurred. Changes in the outlook and the knowledge of AIDS were due to the positive influence of intensive education directly at work places.     

Estimation of the incidence of HIV infection

The aim of the method of 'back projection' is to provide estimates of the number of new infections with the human immunodeficiency virus (HIV) as a function of time, by using the numbers of diagnoses of the acquired immune deficiency syndrome (AIDS) together with information on the distribution of the incubation period between infection and diagnosis. Here, the method is investigated with particular reference to cases of HIV infection and AIDS in the United Kingdom.     

HIV infection in the penitentiaries of Ukraine

In connection with a sharp increase of the number of HIV-infected persons in the Ukraine the natural growth of the number of such persons in penitentiary institutions was registered, starting from 1995 (455 persons in 1995, 2,937 persons in 1996, 2,779 persons in 1997 and 173 persons during 5 months of 1998). 83% of HIV infection persons were drug addicts introducing drugs intravenously. In 1997 the strategy of decreasing the risk of infection in penitentiary institutions was worked out in collaboration with UNAIDS experts: repressive and isolation measures were replaced with measures aimed at the "decrease of harm". Special attention is given to circumstances aggravating the epidemic situation in HIV infection, and particularly at the sharp growth of morbidity in tuberculosis and syphilis (10.6 and 10.3 times respectively in 1997 in comparison with 1993). In addition, in 1997 the number of person having drug addiction was noted to increase 2.3 times in comparison with 1993. The necessity of taking constant information and educational measures aimed at decreasing the risk of the spread of HIV infection is emphasized.     

Children, adolescents and HIV infection

The analysis of the occurrence of HIV infection in adults, children and adolescents under 18 years of age on the basis of statistical data by February 1, 1997, is presented. The total number HIV-infected persons registered by this date was 6,232; among them 902 (14.5%) were children and adolescents. 267 children were infected in the hospital focus of HIV infection; of these, 80 children (30%) died of AIDS during the period of 1989-1997. In 1992 only 16 adolescents, HIV infected were registered, while in 1995 the number of HIV-infected adolescents was 34, in 1996 their number rose to 144 and in 1997, to 435. The main cause of adolescent infections (80%) was the intravenous injection of narcotic drugs.