Open this photo in gallery A doctor is seen labelling protein samples at one of the labs developing a COVID-19 vaccine, in Rockville, Maryland, in a March 20, 2020, file photo. ANDREW CABALLERO-REYNOLDS/AFP/Getty Images

A Chinese ban on the sale of wild animals has frozen the export of monkeys used for pharmaceutical research, turning a measure to prevent future outbreaks into a new obstacle in the fight against the pandemic.

On Jan. 26, the Chinese government temporarily banned the transport and sale of wild animals after a deadly new coronavirus began to spread through a Wuhan market that advertised the sale of live cats, dogs, snakes, rats, foxes, civets, monkeys and other creatures. Less than a month later, China permanently outlawed all trade in wild terrestrial animals, a move praised by international wildlife advocacy groups. The ban applies to animals destined for consumption and provides a specific exemption for use in research, subject to “strict approvals” by the government.

Until recently, China supplied roughly 80 per cent of the monkeys imported into the United States for scientific research, according to statistics maintained by the National Association of Biomedical Research, an advocacy group.

Story continues below advertisement

But strict application of the new ban has effectively halted the Chinese trade in research monkeys, local scientists and breeders said in interviews. Foreign shipments have been frozen, and even domestic researchers have struggled to secure government approval to acquire what scientists call “non-human primates” amid a worldwide race to develop a vaccine against COVID-19.

“Not only have the sale and transport of test monkeys been stopped, but all exports are banned as well. Many companies and institutes are unable to use test monkeys, because they just can’t,” said Qin Zirui, manager of Guangdong Blooming-Spring Biological Technology Development Co. Ltd., a major Chinese supplier of research monkeys whose facilities sprawl over 70 hectares.

Domestic COVID-19 vaccine researchers can only access monkeys after going through a difficult government approval process, Ms. Qin said. She is not aware of such an avenue for foreign researchers. As a result, “the export ban and resultant shortage of monkeys will become an obstacle for other countries in their development of a COVID-19 vaccine,” she warned.

Monkeys have been used by Chinese researchers to test susceptibility to COVID-19 infection and to examine immunity after recovery. They have also been used in both domestic and international vaccine development programs.

The availability of research animals is a key concern for scientists around the world as they seek to test the safety and effectiveness of vaccines before launching human trials. In the United States, the Jackson Laboratory is racing to produce mice that have been genetically modified to be susceptible to COVID-19. It aims to make 800 such mice available per week – but not until the end of June. In Australia, the supply of research ferrets is down to a few months.

”There’s a severe challenge to get access to the mice for the drug trials,” said Rob Grenfell, the health director of the health and biosecurity business unit at the Commonwealth Scientific and Industrial Research Organisation, Australia’s national science research agency. “And ferrets only breed once a year, which makes them very precious,” he said.

Limited supplies mean scientists in Australia are having to make difficult decisions about which trials to conduct. “These are unprecedented times. We’ve never been in this position before,” Dr. Grenfell said. For now, there are enough ferrets for essential studies to proceed. But “ring me in a few months and I might tell you that the last one has gone in,” he said.

Story continues below advertisement

In China, meanwhile, the wildlife ban has placed a freeze on the supply of monkeys for tests. In normal times, China produces roughly 70,000 test monkeys a year. But since the ban, “our business has entered a period of stagnation,” said Zhang Wen, general manager of Beijing Sun-rising Technology Co. Ltd., a trading brokerage for research animals. “All of the animals are sealed and preserved, which means nobody can move them,” he said.

At the same time, the Chinese government has opened what Mr. Zhang called “a special channel for COVID-19-related requests.” But even that channel has proven complicated to access.

In February, Zhuhai Lifanda Biotechnology Co. Ltd. began monkey tests on a new COVID-19 vaccine candidate, but only after what chief executive Peng Yucai described as “a complicated process with many different applications to be stamped by all layers of government.” The company’s partners included the Academy of Military Medical Sciences, and it ultimately managed to secure eight monkeys for testing. From a regulatory perspective, “we would typically need more than that number,” Mr. Peng said. “But because of the tensions and limits with the epidemic, that was the best we could do.”

Another COVID-19 vaccine developer in China confirmed encountering problems securing monkeys for test use.

However, Mr. Peng cautioned against worrying that a shortage could stifle vaccine development, which will require only a fraction of the monkeys available around the world. Research monkeys are also exported from Cambodia, Mauritius and Vietnam, although China has been the largest supplier. And some COVID-19 vaccine trials have already moved on to human tests.

The use of monkeys for research is controversial, but their physiological similarities to humans – especially their pulmonary and immune systems – have made them invaluable for studying lung diseases and vaccines. Their use in research is growing, up more than 20 per cent in the U.S. between 2015 and 2017, according to the U.S. Department of Agriculture.

Story continues below advertisement

At the same time, animal rights groups that decry the practice have succeeded in creating obstacles to the shipment of monkeys for medical research. Among major air carriers, only Air France remains willing to transport them, and People for the Ethical Treatment of Animals last week renewed calls for the airline to end the practice, which PETA said “is dangerous and poses a serious public health risk” while involving animals in “pointless and deadly studies.”

Advocates for animal research, meanwhile, have sought to use the urgency of the coronavirus pandemic to argue in favour of testing on primates and others. The European Animal Research Association (EARA) has called for the classification of research animals as being of “national importance” to speed their clearance through borders.

“If they don’t move these research animals, not just COVID-19 but all research is going to dry up, because we need to access the animals,” said EARA executive director Kirk Leech.

He also suggested another motive for China’s export ban: in order to favour its own researchers. “China has a strategy, ultimately, to become a centre for neuroscience in the world,” he said. “Therefore, tactically, they may or may not want their airlines long term to transport animals.”

With reporting from Alexandra Li

Sign up for the Coronavirus Update newsletter to read the day’s essential coronavirus news, features and explainers written by Globe reporters.