ESTIMATES OF RECENT HIV INFECTION IN THE POPULATION BY FREQUENCY OF OCCURRENCE P24 ANTIGEN AND IN THE KIT DISTINGUISH RECENT FROM LONGSTANDING INFECTION

Abstract

Aim: to compare the incidence of recent cases of HIV infection in the population, recorded by the presence of p24 antigen and in thekit distinguish recent from longstanding infection.Materials and methods. Evaluation of recent HIV infection was carried out through studies of two cohorts of patients: 1) persons with negative / undetermined result of an immune blot and p24 antigen; 2) individuals with positive immune blot who were additionally studied using a test system to determine the duration of infection. Randomly in 2011, 2013, 2014 and 2015, 22%, 17%, 44% and 6% of all newly identified patients with a positive immune blot, respectively, were examined. Statistical processing, correlation coefficient and confidence intervals were calculated using Student’s t-test.Results. There is a close correlation between the detection rate of the p24 antigen of HIV and the frequency of occurrence of recent cases of infection registered among newly identified individuals with positive immune blot (the period of probable infection is less than 9 months). Correlation coefficient =0,91, p<0,05.Conclusion. The established dependence allows one to estimate the recent cases of infection in the population by a calculated method using only the frequency of occurrence of the p24 antigen included in the standard diagnostic algorithm of HIV infection. A formula is proposed in accordance with which it is necessary to add 0,6±0,2 to the frequency of occurrence of the p24 antigen expressed per 1000 individuals covered by screening. With a probability of 95%, the true value of the frequency of occurrence of recent cases of infections in a population will be in the calculated confidence interval.