KI’s oldest macaques and their contribution to research

The group were KI’s oldest macaques – the so-called “old ladies”, at Astrid Fagræus’ laboratory – and they have contributed to knowledge that is directly applicable to human health, including COVID vaccines, since they came to KI. The macaques’ unique biological resemblance to humans makes them invaluable for understanding disease progression, testing drugs and developing new treatments.

At the end of their lives, the five macaques were involved in research concerning how the immune system and vaccines interact, and to evaluate whether long-lasting protection against tuberculosis could develop in older individuals. Their tissues have also been utilised to contribute to new knowledge about, among other things, Alzheimer's disease, Parkinson's disease, multiple sclerosis (MS), ALS, psychiatric diseases and cancer. They continue to contribute to research after their lives have ended.

Thanks to research, improved diagnostics and the development of treatment and new drugs can become a reality for both humans and animals. The COVID-19 pandemic clearly demonstrated just how crucial primates were to the development of the COVID-19 vaccines that saved millions of lives.

Ethical considerations

The decision to euthanise the “old ladies” was made after thorough investigations and ethical considerations by researchers in consultation with veterinarians, ethologists, KI’s animal welfare body and animal care staff. This ensured that the macaques were able to end their lives in the most humane way possible. 

It would have been far worse for animal welfare to allow the macaques to develop age-related diseases, likely resulting in suffering and the need for emergency euthanasia. It is well known that when an individual within a group dies, the remaining animals experience significant stress as macaques establish new hierarchies through aggression.

The alternative of rehoming the older monkeys, to “retire” them, would have led to considerable stress and suffering for the entire group. The process would have required arduous transport followed by adaptation to a new environment and establishment of new hierarchies. It would not have been consistent with prioritising animal welfare. 

Animal welfare is always central to KI’s decisions. The five macaques came to KI when they were three years old, and they have spent most of their adult lives together. The macaques’ living environment at KI has been designed to resemble their natural habitat as closely as possible, and only specially trained animal care staff, ethologists and veterinarians have been permitted to handle them. 

They were used to achieve the greatest possible scientific benefit and will therefore contribute new knowledge in several research projects for a long time to come.