6. What is the relation between age and chronic infection?

It depends on the age at which you get infected in terms of the probability that you are going to have a chronic infection. If you’re infected at birth or in the first few years of life, then you have an extremely high risk of developing a chronic infection. One of the reasons that in China there are very large numbers of hepatitis B carriers is that mothers are infected. They infect their babies at birth or shortly after birth. And ninety percent of those babies go on to be chronically infected usually for their lifetime. And that decreases as you get older. So from one to five years, thirty percent of children who are infected develop chronic infection. But after five years, that falls to five or six percent.