(Yicai Global) March 19 -- The world's first nucleic acid Covid-19 vaccine was administered to a human earlier this week.

The United States' Food and Drug Administration did due diligence, said Kizzmekia Corbett, a researcher at the National Institutes of Health's Vaccine Research Center who is in charge of the project. "Trust me ... or it would have been sooner," she added, reacting to doubts about the vaccine trial.

A 43-year-old Seattle woman, Jennifer Haller, took the vaccine on March 16, according to media reports. The clinical trial recruited 45 volunteers. Haller will also take a second shot after 28 days. Researchers will observe how the vaccine elicits an immune system response in the human body after two injections.

American biotech firm Moderna developed the vaccine jointly with the NIH via its mRNA nucleic acid vaccine research and development platform and is responsible for the production of vaccine preparations. It is worth noting, however, that Moderna has not previously had any successful human vaccine products.

It took just 65 days from the release of the novel coronavirus' entire sequence to the injection of the first vaccine into a human. But the developers did not publish detailed animal test data before human trials of the vaccine, which has led to doubts.

Corbett countered that Moderna's mRNA platform has been used in humans multiple times, and during the MERS spike and SARS spike as well.

But Prof. Frederic Tangy, head of the Viral Genomics and Vaccination lab at France's Institut Pasteur, which is responsible for the Covid-19 vaccine development, told Yicai Global that before human trials of the vaccine the developers should have at least made public detailed mice data, and then tested it on primates.

Rodent, Chimp Tests

The vaccine has been tested on mice, and data results were obtained on Feb. 21, Corbett said. The immune response of the mice was as expected, suggesting that the vaccine could also be effective in humans but further evaluation was needed, she added.

Chinese scientists had conducted vaccine tests on primates. Corbett did not confirm to Yicai Global whether they are advancing the tests on large animals. Primate tests are not necessary in vaccine development, at least the FDA has not stipulated that, according to an American scientist who participated in the development of the SARS vaccine.

Peter Hotez, dean of the National School of Tropical Medicine at Baylor College of Medicine, is cautious about using new technology platforms such as mRNA to develop vaccines. He told Yicai Global that biotech companies often have no track record of successful vaccine development or approved vaccines, so it could take years and a lot of risks for them to develop successful ones.

Speaking to Yicai Global, Richard Ebright, professor of chemistry and chemical biology at Rutgers University, said that primate experiments are usually needed, but given the seriousness of the Covid-19 pandemic, it is understandable to go directly to human trials.

Corbett acknowledged that the safety risks of the vaccine will take some time to assess. The NIH is preparing for phase 2 clinical trials.

Editors: Xu Wei, Peter Thomas