Hepatitis B: An Overlooked STI, a Silent Threat, a Global Disease

Abstract

In the Western world, exposure to hepatitis B virus (HBV) occurs in adulthood via sexual or percutaneous transmission. One-third develop acute hepatitis, while half undergo a subclinical course. Both groups acquire antibodies. The remaining 5-10% of adults develop chronic HBV, the majority of whom are immunocompromised (HIV, chronic renal dialysis or immunosuppression). In endemic regions, primary infection occurs perinatally. Nearly 90% of neonates become chronic HBV carriers. While neonates are at high risk in endemic regions, sexual exposure remains the most common risk factor in the United States. Populations at risk are those with infected partners, multiple partners, or samesex male partners. Untreated, 25-40% of chronically infected individuals develop cirrhosis and hepatocellular carcinoma (HCC). Following the discovery of HBV, Blumberg also developed an HBV vaccine using HBV-infected human plasma. Produced during the AIDS epidemic, while highly efficacious, recombinant vaccine replaced plasma because of concern the plasma could be coinfected. The 1980s yielded another triumph in the fight against HBV. Again, as HIV came to the forefront of public and political attention, research began in the field of anti-HIV drugs. The anti-HBV drugs used today, starting in 1998, were actually discovered to be efficacious in trials developed for HIV patients. HIV-patients coinfected with HBV showed regression of HBV while on HIV therapy. Currently, these therapies delay disease progression and reduce the incidence of HCC. Now armed with both preventative and therapeutic measures for HBV, coupled with increased awareness and education, the eradication of HBV as we move into the 21 st century seems within grasp.