Coronavirus vaccine trial: First dose administered to participant

According to the National Institute of Allergy and Infectious Diseases, the study aims to enrol 45 healthy adults over a six-week time frame. Each participant will receive two injections, about a month apart, in varying doses.

The study, which is a Phase I trial, is meant to establish that the vaccine is safe and induces a desired response from participants' immune systems. Proving that the vaccine is effective in preventing Covid-19 infection, however, will require follow-up studies involving many more participants, which will take many more months, experts say.

In a statement, NIAID director, Dr Anthony Fauci (pictured), said: "Finding a safe and effective vaccine to prevent infection with (the novel coronavirus) is an urgent public health priority.

"This Phase 1 study, launched in record speed, is an important first step toward achieving that goal."

CNN reports the the vaccine, which uses genetic material called messenger RNA, was developed by NIAID scientists in collaboration with the biotech company Moderna.

The agency credited the speed with which it stood up a Phase I trial to its prior studies on related coronaviruses SARS and MERS. Scientists had previously worked on an experimental MERS vaccine targeting a protein on the virus' surface, which gave them a "head start for developing a vaccine candidate to protect against Covid-19," the statement said.