over a quarter of a billion people around the world, HBV is not known simply for its
popularity. As a leading cause of cirrhois and liver cancer (hepatocellular carcinoma),
HBV is also the first example of a successful recombinant vaccine
for human infectious disease, making future preventative tactics for diseases such as HIV
more of a reality.
In Africa and Asia, nearly a quarter of the population are carriers of HBV with 2-10% being chronically infected. Patients with chronic infection generally remain asymptomatic for years until liver cirrhosis (degeneration of the liver) or hepatocellular carcinoma (liver cancer) develop. The rest of the cases are acute HBV infections, with 20-35% experiencing abnormal liver function and jaundice (yellowish skin due to liver cell death). A long incubation period of 30-180 days allows the virus to replicate.
Men are almost twice as likely to develop chronic hepatits B as women; whereas the vast majority of neonatal exposures develops into chronic infection, showing HBV to be endemic.