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An experimental COVID-19 vaccine protected the monkeys from contracting the viral infection, according to an unrevised report. The new vaccine has now entered clinical trials in china to test the drug in humans.
Although the animal study, published April 19 in the prepress database bioRxiv, not formally reviewed, scientists turned to Twitter to share their first impressions.
“So this is the first ‘serious’ preclinical data I have seen for a real vaccine candidate,” Florian Krammer, professor in the Department of Microbiology at the Icahn School of Medicine at Mount Sinai, tweeted on April 22. Before being tested on healthy humans, the vaccines undergo so-called preclinical testing on animals. The experimental vaccine, developed by the Beijing-based Sinovac Biotech company, showed promising results in rhesus macaques before entering human trials, Krammer noted.
“I’m a fanatic,” he added in another. cheep.
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Now in clinical trials, 144 people will be given multiple doses of the vaccine to determine if it is safe, which means it does not cause dangerous side effects, according to ClinicalTrials.gov. The vaccine would then go on to efficacy trials with more than 1,000 additional people to determine if it triggers an adequate immune response, Meng Weining, senior director of overseas regulatory affairs for Sinovac, he told science magazine.
The Sinovac vaccine it contains an inactivated version of SARS-CoV-2, the virus that causes COVID-19. By introducing an inactive virus into the body, the vaccine must trigger immune system to build antibodies that target the pathogen without triggering a real COVID-19 infection. When administered to rhesus mice, rats and macaques, the vaccine caused the production of these antibodies, according to the bioRxiv report.
“This is an old-fashioned technology,” which would make it easier to manufacture the product, Krammer wrote on Twitter. “What I like the most is that many vaccine producers, also in low- and middle-income countries, could make such a vaccine,” he added in an interview with the journal Science.
To test whether the antibodies generated by the vaccine would neutralize SARS-CoV-2, the research team collected samples from mice and rats and exposed those antibodies to 10 different strains of SARS-CoV-2 in test tubes. The various strains of SARS-CoV-2 were originally sampled from patients in China, Italy, Spain, Switzerland and the United Kingdom, and represent, to some extent, the circulating populations “of SARS-CoV-2, according to the report.
The antibodies generated by the vaccine were able to neutralize the various strains, suggesting that the vaccine could “exhibit potent neutralization activities against SARS-CoV-2 strains circulating worldwide,” the research team wrote. The finding that the antibodies could neutralize different strains “provides strong evidence that the virus is not mutating in a way that makes it resistant to the # COVID19 vaccine. Good to know,” Mark Slifka, professor of molecular microbiology and immunology at Oregon University of Health and Science, tweeted in response to Krammer’s thread.
After their test tube experiments, the research team tested how well the vaccine worked on rhesus macaques, a type of monkey that develops. “Symptoms similar to COVID-19“When infected with SARS-CoV-2. Twelve monkeys received a placebo treatment, a medium dose of the vaccine, or a high dose of the vaccine; all injections were administered in three doses over two weeks.
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Eight days after administering the final dose, the researchers introduced the SARS-CoV-2 virus into the monkey’s lungs through a long tube. While the virus replicated widely in the placebo group, it triggered symptoms of pneumoniaAll of the vaccinated monkeys “were largely protected against SARS-CoV-2 infection,” the authors wrote.
Those in the high-dose group had the best results: One week after being exposed to the virus, the high-dose group showed no detectable SARS-CoV-2 in their lungs or throats. Some virus could still be detected in the medium-dose group after one week, but the infection still seemed to be well controlled. Since the vaccinated monkeys did not develop adverse side effects, the results “give us a lot of confidence” that the vaccine will work in humans, Meng told the journal Science.
Despite this apparent success, Douglas Reed, an associate professor of immunology at the University of Pittsburgh who was not involved in the research, told the journal Science that the number of monkeys included in the study “was too small to produce statistically significant results.” . Reed also expressed concern about how Sinovac’s team developed the coronavirus for use in vaccinated monkeys, claiming that the procedure could have altered the virus so that it was not the version that infects humans.
However, except for small data, the small study “[lessen] concern “about certain side effects a COVID-19 vaccine could cause,” added Reed.
Sinovac’s team found that the vaccinated monkeys showed no adverse side effects, such as fever, weight loss, or a phenomenon called “antibody dependent improvement (ADE),” in which the body reacts. worst to a virus after vaccination, instead of developing protection. Previous vaccines tested against other coronaviruses in animals and the human coronavirus SARS triggered ADE in early animal studies, so there is some concern that a SARS-CoV-2 vaccine may do the same, Live Science previously reported.
Even if the promising results in monkeys carry over to humans, “whether there is lasting protection remains a key question,” Lucy Walker, professor of immune regulation at University College London, who was not involved in the research, wrote on Twitter. In other words, if the vaccine protects humans against COVID-19 infection, we don’t know how long that protection would last.
“But encouraging data [from the bioRxiv study]: no ADE, no obvious surprises, “added Walker.” Many vaccines are under development, increasing the chances of success. “
Originally published in Living science.
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