Expert Panel Assesses Animal Models for COVID-19 Research

Angela Rasmussen, a virologist and associate research scientist in the Center for Infection and Immunity at Columbia University Mailman School of Public Health, is a member of an international panel assembled by the World Health Organization (WHO) to develop animal models for COVID-19 to accelerate the testing of vaccines and therapeutic agents. The WHO panel published a review of its findings to date in the journal Nature today.

The first author is César Muñoz-Fontela at the German Center for Infection Research. Rasmussen contributed text and references in a section about mice.

The 64-member multidisciplinary panel has been meeting weekly since February to discuss new data in preclinical models—mostly animals, but also in organ-on-a-chip systems. They covered everything from the basics of model development to using models for drug and vaccine screening. Their goal: help the larger scientific community understand the current state of the field and select the appropriate animal models for their COVID-19 research. Going forward, the panel will continue to share data obtained with animal models already under development, as well as use the models to investigate gaps in knowledge about SARS-CoV-2 and COVID-19.

Included in the new paper is a list of animal models and their various strengths and weaknesses in their ability to mimic various aspects of COVID-19 disease in humans—mice, ferrets, hamsters, non-human primates, mink, cats, and bats. Already, several vaccine candidates have shown protection in rhesus macaques, and both cynomolgus and rhesus macaque models have been useful for the testing of therapeutic agents. Because some models have different susceptibility to SARS-CoV-2 infection and develop different severity or different manifestations of COVID-19, some models are better than others.  

Rasmussen, who is currently finishing a study using samples from a rhesus macaque model, explains: “The rhesus macaque, for example, develops moderate COVID-19 disease, so it’s not useful for studying lethal COVID-19 but is very useful for studying vaccines. The ferret doesn’t get very sick at all, but their respiratory tracts are physiologically more similar to humans than mice, so they are useful for studying transmission. Cats can be infected by humans, so it’s also possible that they could transmit the virus to humans, and thus it’s helpful to understand how the virus replicates in that model,” she says.

“All these models have utility in the future for a variety of studies: testing therapeutics and vaccines, studying pathogenesis in detail, studying transmission modes and routes, characterizing susceptibility across species and investigating possible new reservoirs for the virus, such as cats, and identifying host features associated with susceptibility,” she adds.