'Second chance': Chimps used in hepatitis B experiments get health checks in Liberia

Veterinary teams at a Liberian sanctuary conducted comprehensive health checks — including dental exams, X-rays and blood tests — on chimpanzees once used in American hepatitis B vaccine research. More than 400 chimps were used in the experiments from the 1970s to the early 2000s; 60 survivors, now 30 to 35 years old, have been under Humane World for Animals' care since 2015.