United States is facing a shortage of monkeys for COVID-19 vaccine research

The race for a coronavirus vaccine to end the pandemic has suddenly created and escalated the demand for monkeys.

Before the drug is tried on humans, monkeys are used in preclinical trials to test a vaccine’s safety and effectiveness. But with more than 100 vaccines in development around the world, there aren’t enough monkeys to go around.

“There is a shortage,” said Dr. Skip Bohm, associate director and chief veterinary medical officer of the Tulane National Primate Research Center.

Nonhuman primate research centers have been strained in recent years because of restrictions on imported monkeys from countries like China and India, and a lack of funding to support domestic breeding.

While animal rights advocates condemn using primates in experiments, researchers say it’s essential for development of medical science.

The National Primate Research Centers try to use the smallest number of animals necessary for a valid scientific result, according to the centers’ website. Unfortunately, it’s not currently possible to completely replace animal models with computer simulations or cell cultures.

“We all hope there’s a day we don’t have to use animals in research but right now … not all humans are going to submit for an examination where they get regular x-rays, regular CT analysis or blood analysis,” Bohm said.

Rhesus monkeys, or Rhesus Macaques, are the most commonly used monkeys for preclinical trials because they share about 93% of their genes with humans, according to the National Primate Research Centers.

Jay Rappaport, director and chief academic officer of Tulane’s National Primate Research Center, says the species has been used in research for years, so scientists are most familiar with how its immune system combats pathogens, especially coronaviruses.

“Their immune systems and immune responses are very similar to what you see in humans and they can give you a very good idea of safety and efficacy in vaccines,” he said.

Tulane’s primate research center has about 5,000 monkeys but only about 500 are used for research in a normal year because of age, health and colony dynamics. This year, Bohm estimates the same number of primates might be needed across the centers just for COVID-19 research alone.

To satisfy the demand, NIH and research centers have had to collaborate more closely than ever. NIH created a committee to prioritize COVID-19 research while centers developed master protocols to optimize research, including sharing control groups.

“By doing this, this saves us probably half of the animals,” Rappaport said.