Estimation of HIV (Human Immunodeficiency Virus) and HBV (Hepatitis-B Virus) Infectious Titers in Human Fluids and Tissues

摘要

A four task project was conducted to assess the risks of human immunodeficiency virus (HIV) and hepatitis-B virus (HBV) infection for health care workers. This was the first of the tasks and includes a basic biological description of the two viruses and assess the available information on the distribution of infectious titers in the patients that might be sources of occupational exposure. Two potential vectors of occupational infection were cited: free viral particles and infected cells. Data concerning the distribution of HIV antigen titers in blood suggested that symptomatic stages of HIV infection are associated with increased median titers of free virus and reduced variability in viral titers. One set of serial dilution measurements interpreted in terms of distributions of cell mediated infectious titers for one specific population group, asymptomatic seropositive people, indicated that the median cellular infectious titer for this group may exceed the titer due to free viral particles by approximately 500 times. The authors conclude that a comparison of these data with the HIV titer data helps explain the much greater frequency of occupational transmission for HBV than for HIV.