Hepatitis B virus (HBV) infection is a global public health problem despite the availability of an effective vaccine. It is estimated that there are 248 million HBV carriers in the world, of whom roughly 600,000 die annually from HBV-related liver disease. The implementation of effective vaccination programs in many countries has resulted in a significant decrease in the incidence of new hepatitis B infection. Nevertheless, HBV infection remains an important cause of morbidity and mortality.
Transmission: Unscreened blood and blood products and mother-to-child transmission is the predominant mode of transmission in high-prevalence areas. Breastfeeding does not appear to increase the risk of transmission. In comparison, horizontal transmission, particularly in early childhood, accounts for most cases of chronic HBV infection in intermediate-prevalence areas, while unprotected sexual intercourse and injection drug use in adults are the major routes of spread in low-prevalence areas.
Clinical Manifestations: The spectrum of clinical manifestations of hepatitis B virus (HBV) infection varies in both acute and chronic disease. During the acute phase, manifestations range from subclinical or anicteric hepatitis to icteric hepatitis and, in some cases, fulminant hepatitis. During the chronic phase, manifestations range from an asymptomatic carrier state to chronic hepatitis, cirrhosis, and hepatocellular carcinoma. Extrahepatic manifestations can also occur with both acute and chronic infection. Approximately 70 percent of patients with acute hepatitis B virus (HBV) infection has subclinical or anicteric hepatitis, while 30 percent develop icteric hepatitis. The incubation period lasts one to four months. A serum sickness-like syndrome may develop during the prodromal period, followed by constitutional symptoms, anorexia, nausea, jaundice, and right upper quadrant discomfort. The symptoms and jaundice generally disappear after one to three months.
Treatment: Direct acting antivirals i.e Entacavir and tenofovir are now preferred on interferons.
Immunization: Incidence of disease has markedly reduced due to availability of recombinant vaccine. Three doses are recommended i.e. 0, 1 and 6 months. Anti-HBs titers > 10 IU/ml are considered protective against disease.
Prevention: Proper screening of blood and blood products. Avoid high risk behaviors. Children born to HBV positive mothers must be vaccinated at birth along with one dose of immunoglobulin. Promoting HBV vaccination among all susceptible people.