The vaccine, which uses inert pathogens from the virus causing the covid-19 disease, was administered to eight monkeys, who were artificially infected three weeks later, according to research published by pharmaceutical giant Sinovac Biotech.
"The four monkeys that received the vaccine in high doses did not show any detectable trace of the virus in their lungs, seven days after the contamination," said the laboratory, which published the results on 19 April on the bioRxiv website.
Another four apes, to whom the vaccine was administered in a less strong dose, had a high viral load in the body, but managed to resist the disease.
These results must now be subject to a new evaluation by the specialists, before being validated by the scientific community.
Sinovac, a Nasdaq-listed company, began clinical trials of the same vaccine in humans on 16 April.
Questioned by the French news agency AFP, the laboratory declined to comment on this matter.
"These are the first serious preclinical data I have ever seen on an experimental vaccine," virologist Florian Krammer, from the Icahn School of Medicine in New York, commented on Twitter.
"The question is whether this protection is long-lasting," noted immunologist Lucy Walker of University College in London.
In addition to the Sinovac project, Beijing approved two other experimental vaccines launched, on the one hand, by the Military School of Medical Sciences and the CanSino biotechnology group, quoted in Hong Kong, and, on the other hand, by the Biological Products Institute and the Institute of Virology from Wuhan, the city where the coronavirus emerged, at the end of last year.
The American laboratory Moderna announced simultaneously in mid-March that it was also carrying out clinical trials for an experimental vaccine in the United States.
Pharmaceutical groups and research laboratories around the world have launched a race against time to develop treatments and vaccines against covid-19, which has killed more than 190,000 people, in about 2.7 million infected citizens. Experts are using several new technologies.
The estimated period for a vaccine is between 12 and 18 months, at least.