There is a common perception that hepatitis B is a disease of adults, transmitted via sexual intercourse or needles. If that were the case, vaccinating babies would be nonsensical.
But the reality is that hepatitis B is a disease that affects many infants and young children worldwide. And unfortunately, the younger you get the virus, the more likely it is to become a chronic infection that can cause cirrhosis or liver cancer. While most diseases are more severe if you get them as an adult, hepatitis B is paradoxically worse if you get it young, writes Christopher Labos, a Montreal doctor and an associate with the McGill Office for Science and Society. He also co-hosts a podcast called The Body of Evidence.