Chimpanzees have been shown to be exquisitely susceptible to human hepatitis viruses, without themselves developing clinical illness, thus providing an important model for studies on these agents. Chimpanzees have contributed substantially to human welfare by making possible the development of hepatitis B vaccines, which now prevent development of cirrhosis and hepatocellular carcinoma in millions of people.

Many animal rights activists consider that all research carried out with animals is indefensible. This would apply especially to research with chimpanzees. I assume that chimpanzees are the closest relatives to humans and that they deserve ethical considerations which are similar to those accorded humans. Nevertheless, I believe that it is ethically justifiable to carry out certain types of experimentation with this species, as it is also with humans. I welcome the opportunity to defend this position here.