Limitations on the Use of Chimpanzees in Biomedical Research

Ellen P. Carlin

The scientific and animal welfare communities have been abuzz of late related to announcements on the status of the captive chimpanzee, a great ape and human beings’ closest genetic cousin.  Implementation of two federal policies (one final, one under consideration) will affect whether and how chimpanzees can be used in U.S.-funded research.  Two agencies have proposed two different approaches to the status of the animals.   The proposals differ based on the unique authorities of the agencies, but they share some common implications.

The proposals – one to limit biomedical research in chimpanzees, the other to classify them as endangered – have generated both praise and misgivings, largely pitting those who support the policies on animal welfare grounds against those who object to research limitations that could slow or halt medical progress in certain areas.  Chimpanzees have commonly been used in virology research, most notably for hepatitis and HIV studies.  Much of the unease expressed by scientists and others has been with respect to the potential impacts on development of a hepatitis C vaccine.  Even if waivers were granted, the process could lead to delays.  The restrictions could also impact research flexibility on viral diseases that have not yet emerged.  Other scientists and welfare champions, however, believe the benefits outweigh the costs.  In light of advances in in vitro, in silico, and alternative in vivo models, combined with the significant reductions in wild chimpanzee populations in recent decades, they deem further protections to be warranted.

 National Institutes of Health announces cessation of most NIH-funded biomedical research on chimpanzees


Nearly 700 chimpanzees are owned or supported by the National Institutes of Health (NIH), an agency of the U.S. Department of Health and Human Services and the foremost federal biomedical research agency in the United States.  In 2010, the NIH commissioned the Institute of Medicine (IOM) to review the scientific need for chimpanzees in NIH-funded research.  Specifically, the IOM was tasked to describe the unique biological/immunological characteristics of the chimpanzee that make it a necessary animal model.


The IOM concluded in 2011 that most biomedical research using chimps was unnecessary, with two potential exceptions:  completion of a limited number of monoclonal antibodies in development, and possibly the development of a prophylactic hepatitis C virus vaccine (the IOM committee reached no consensus on whether a preclinical challenge study using the chimpanzee model was necessary).  The committee recommended that chimpanzee use in biomedical research be limited to those studies for which no other suitable model is available, for which the research in question could not be performed ethically on human subjects, and for which forgoing the use of chimpanzees would significantly slow or prevent important advancements in life-threatening or debilitating conditions.  The committee also recommended limitations on the use of chimps in comparative genomics and behavioral research.

The NIH’s Director, Dr. Francis Collins, accepted the recommendations, and in February 2012 an NIH advisory group was established to determine plans for implementation.  The group issued its proposal in January 2013 and sought public comment.  On June 26, 2013, having received comments and finalized the recommendations, the NIH announced that it would significantly reduce the use of chimpanzees in NIH-funded biomedical research and retire most NIH-funded chimps into the Federal Sanctuary System, operated by Chimp Haven.  Up to 50 chimps will be maintained for future research that meets the IOM and NIH criteria, and a review panel will be established to consider research proposals that would use these chimps.


In a written statement, Dr. Collins explained the decision, stating, “Americans have benefitted greatly from the chimpanzees’ service to biomedical research, but new scientific methods and technologies have rendered their use in research largely unnecessary.”


The federal government has been moving in this direction since at least 2002, when the Chimpanzee Health Improvement, Maintenance and Protection (CHIMP) Act was signed into law by President Clinton.  The Act established a sanctuary system to provide for the retirememt of federally owned or supported chimps deemed no longer needed for research.


U.S Fish and Wildlife Service proposes to include captive chimpanzees on its endangered species list


In a related policy development, the U.S Fish and Wildlife Service (FWS), an agency of the Department of the Interior, issued a proposed rule on June 12, 2013 that could significantly impact research with chimpanzees.  Resulting from a public petition, the proposal sets out to list all chimpanzees (whether wild or captive) as endangered under the Endangered Species Act of 1973 (the Act).  If finalized, the rule would extend the protections of the Act to captive chimpanzees in the United States, which have thus far been exempt.


The wild chimpanzee was listed as “threatened” under the Act in 1976, but a concurrent “special rule” was issued that exempted captive chimpanzees in the United States.  In 1990, wild chimpanzees were reclassified as “endangered.”  In March 2010, a petition was submitted on behalf of eight groups, including the Humane Society of the United States, the Jane Goodall Institute, and the Wildlife Conservation Society, to remove the exemption for the captive chimpanzees.  FWS reviewed the petition and concurred, prompting proposal of the new rule.  In its proposal, FWS cites the IOM’s conclusion that the need for chimpanzees in research is decreasing, but the threat to the species is not.  The public comment period closes on August 12, 2013, after which point the agency will consider issuing a final rule.


According to FWS, the decision to issue the proposed rule reflects concern over growing threats to chimpanzees, and aligns the species’ status with existing legal requirements by correcting inconsistencies in the application of the law.  Membership of captive chimpanzees in the “endangered species” community would afford these animals protections under the law, which would in turn influence whether and how the animals could be used in research of any kind.  Permits would be required, and would be issued only for those studies deemed to have positive impact on the conservation of the species.  FWS’ press release on the action states that the agency will work closely with the NIH and other stakeholders in the biomedical research community to consider the implications of the proposed rule.