Why scientists are excited by first trial of new Covid vaccine

A U.S company specialising in vaccines has released results from the first stage of human trials of their new Covid-19 vaccine, showing early trial participants have the same neutralising antibody in their blood as those who have contracted and recovered from the coronavirus.

In a press release issued on May 18, pharmaceutical giant, Moderna, said their vaccine, called mRNA-1273, appeared to promote the same immune response to Covid-19 in trial participants as those who had previously had the virus.

While this preliminary result is encouraging, it has only been documented in the first eight people taking part in the first stage of the trial. The first stage was primarily designed to gauge the safety of the vaccine, not its effectiveness in combating the virus, however researchers say the results merit cause for a positive outlook. The second stage of the trial, due to begin in July of this year, will involve a much larger cohort of trial participants and will focus on the vaccine’s ability to stimulate an immune response that will protect the host from the Covid-19 virus.

The first stage of the trial shows that the vaccine appears to have a good safety profile – the first hurdle in vaccine development. Trial participants who received a low and medium strength dose of the vaccine reported no or low-level side effects, however some side effects were noted with those participants given a high dose. Interestingly those given the low and medium strength doses still showed more-than-adequate levels of neutralising antibodies in their blood samples.

Representatives from Moderna say the vaccine has been shown to stop the virus replicating in the lungs of mice in early animal trials – another encouraging indicator.

“With today’s positive interim Phase 1 data and the positive data in the mouse challenge model, the Moderna team continues to focus on moving as fast as safely possible to start our pivotal Phase 3 study in July and, if successful, file a BLA (Biologics License Application with the U.S’s Federal Drug Administration),” said Stéphane Bancel, Chief Executive Officer at Moderna in a statement. “We are investing to scale up manufacturing so we can maximize the number of doses we can produce to help protect as many people as we can from SARS-CoV-2.”

The vaccine is designed to work by introducing a small fragment of the Covid virus’s genetic code into the body – not enough to make the host seriously ill, but enough to jump-start the body’s natural immune system into action and enabling it to develop an effective response against further attacks from the same virus.

The speedy development of the vaccine is due in large part to the extensive body of work already conducted by Moderna, the U.S’s Vaccine Research Center (VRC) and the National Institute of Allergy and Infectious Diseases, into a vaccine for the SARS virus, a close cousin of Covid-19 and a member of the coronavirus family.