Spread of hepatitis-B infections. A seroepidemiologic study

Area of Science:

• Virology
• Immunology
• Epidemiology

Background:

• Hepatitis B virus (HBV) infection is a significant global health concern.
• Understanding the prevalence and subtypes of HBV is crucial for public health strategies.
• Radioimmunoassay (RIA) offers a method for detecting HBV markers.

Purpose of the Study:

• To assess the prevalence of hepatitis B virus (HBV) infections using radioimmunoassay (RIA).
• To determine the distribution of HBV subtypes (HBs Ag and anti-HBs) in different populations.
• To investigate the presence of anti-HBs in immunoglobulin preparations.

Main Methods:

• Solid-phase radioimmunoassay (RIA) for simultaneous detection and quantitation of HBs Ag and anti-HBs.
• RIA used for validation of positive reactions and determination of serum subtype specificity.
• Analysis of sera from various population groups, including healthy individuals, institutionalized subjects, renal patients, and blood donors.

Main Results:

• Neutralizing anti-HBs were found at a prevalence nearly 4-fold higher than HBs Ag, often at low titers.
• High frequencies of HBs Ag and anti-HBs were observed in Italian and Tanzanian populations, institutionalized subjects, renal patients, and blood donors.
• In Italy, 80.2% of HBV markers were subtype 'ay', while in Tanzania, 72.3% were subtype 'ad', with 'w' as a common secondary determinant.
• Low-titer anti-HBs with 'a' and 'd' specificity were detected in standard immunoglobulins from the USA.

Conclusions:

• HBV infection is prevalent across diverse populations, with neutralizing antibodies being more common than the antigen.
• Significant geographical variations in HBV subtypes exist, with 'ay' dominant in Italy and 'ad' in Tanzania.
• The findings contribute to mapping HBV subtypes in Africa and highlight the presence of anti-HBs in immunoglobulin preparations.