Long-suffering laboratory chimps will be given an honorable retirement under a sensible plan announced this week by the National Institutes of Health. They owe their reprieve mostly to their close resemblance to humans, which gave many scientists pause about causing them pain and keeping them in cramped cages, and to scientific advances that make experiments on chimpanzees less vital than they used to be.

The N.I.H., the federal government’s main supporter of biomedical research, announced that most of the chimpanzees it owns or supports — about 310 in all — will be retired in the next several years and moved to sanctuaries from which they cannot be recalled for research. About 50 will be retained for future research that would be conducted under stringent conditions and only if truly necessary. Hundreds of chimps that are privately owned are not directly affected.

The new policy was adopted after two expert groups — the Institute of Medicine and the Council of Councils, a federal advisory committee — concluded that most biomedical research on chimps is unnecessary because the same information can be gleaned through cell-based technologies, new animal models and, when ethically acceptable, testing in humans even without chimpanzee results.

The chief exception may be research on the hepatitis C virus, which infects only two species, chimpanzees and humans, and so cannot be studied in other animals. There is no consensus among experts on whether chimpanzees will be needed to test the effectiveness of a preventive vaccine for hepatitis C or whether it might be feasible, ethically and economically, to test a vaccine’s safety in other animals and then test its effectiveness in humans.