COVID-19 animal research reveals ethical shortcomings

Andrew Fenton and L. Syd M Johnson outline several ethical issues with nonhuman animal research revealed by COVID-19 research


As scientists have raced to understand COVID-19, and develop a vaccine to combat the pandemic, the public has gained a new appreciation for animal research, or so claims an article in The Atlantic. It raises alarms about a “shortage” of monkeys for use in vaccine and other biomedical research. But is it a crisis, or a call for us to think more deeply and critically about the scientific use of animals?

The Atlantic article, in using commodifying language to discuss the monkey “shortage,” treats monkeys as little more than laboratory equipment, things like test tubes and centrifuges. The lack of available monkeys for vaccine research is framed as a problem like PPE and swab shortages. The article also emphasizes that monkeys are needed for vaccine research because of their genetic and biological similarity to humans.  Yet, it avoids the ethical point that such proximity might make monkeys entities of moral concern and not mere equipment.

It is important not to confuse debates about the ethics of animal research with debates about whether the use of animals yields important scientific outcomes. But there is also a scientific problem with the similarity-based arguments for using monkeys: the high fidelity fallacy. What makes an animal or alternative a good model is how well the model reveals what scientists want to know. The more clearly the model does this, the higher its discrimination. But achieving high discrimination doesn’t always require high fidelity (a strong resemblance). Rather, low fidelity models can sometimes perform better and have higher discrimination. When high discrimination models are neglected in favor of high fidelity animal models, and those preferred animals are harmed, it’s an ethics issue.

Photo Credit: Rama. Image Description: Hands in blue medical gloves hold a gray mouse

The Atlantic takes pains to emphasize the high fidelity of monkey models. Monkeys resemble humans more closely than rodents, being more closely related from an evolutionary perspective. Their immune systems are similar, making them better vaccine test subjects. But some rodents get far sicker when infected with SARS-CoV-2 than do the macaques who are the preferred monkey models. Syrian hamsters are rodents who have been used in SARS-CoV-2 research and exhibit a range of symptom severity. Efforts have been made to create mice that carry the human ACE2 receptor that SARS-CoV-2 uses to infect cells in our upper respiratory tract. These modified mice are more readily infected, and more likely to get sick, than their unmodified kin. Overall, it seems that non-primate models offer higher discrimination. The 1980’s HIV-AIDS research with chimpanzees provides another example of a “high fidelity” failure. Although chimpanzees could be infected with HIV, almost none developed AIDS. Ironically, unlike the current monkey “shortage,” this resulted in a “surplus” of chimpanzees. Currently, no single animal model reliably expresses the range of severity of COVID-19 in humans. The best these models can do is get at aspects of the human disease, not its entirety.

The reduction and killing of primates used in COVID-19 research pose additional ethical issues. Monkeys are in short supply in countries like the US, largely because during this pandemic China has stopped exporting the monkeys it breeds. Laboratories have had to collaborate to use the monkeys they do have more efficiently. For example, some labs have the control animals while others have the experimental animals, effectively reducing the number of animals that would ordinarily be used. This reveals that scientists can creatively reduce the number of animals used in research and the “normal” practices don’t live up to the scientific community’s purported commitment to minimize the number of animals used.

Primates used in COVID-19 research are supposedly killed for safety reasons. But this contrasts with the late 20th century US decision that prohibited killing chimpanzees after their use in biomedical research, except where medically necessary (i.e., mercy killing). Killing monkeys fails to value their lives and treats them as disposable tools, despite their similarity to humans and chimpanzees. Any difference of treatment must be justified before it is ethically acceptable, and here, the safety concerns don’t cut it. Macaques don’t reliably express serious disease when infected with SARS-CoV-2, so they don’t present a serious danger to other monkeys, nor is it clearly a mercy to kill those who are infected.

Perhaps the shortage of monkeys is indeed revealing. The high fidelity fallacy persists; pre-pandemic, monkeys were being used in higher numbers than was necessary; and the justification for killing infected monkeys like macaques seems wanting. Importantly, the “shortage” problem might be solved in other ways, using non-animal models. Some vaccine researchers have bypassed animal testing and moved to human clinical trials. Human trials are always necessary for vaccine research, but it’s an open question whether animal trials for SARS-CoV-2 vaccines will help or hinder efforts to develop a vaccine quickly. Perhaps the monkey “shortage” is an opportunity to create better and more efficient ways of doing vaccine research.


Andrew Fenton is an Associate Professor of Philosophy at Dalhousie University.

L. Syd M Johnson is an Associate Professor at the Center for Bioethics & Humanities, Upstate Medical University. @LSydMJohnson