Moderna’s Covid-19 vaccine set for testing in 30,000 volunteers

29 Jul 2020

Image: © weyo/

If the vaccine proves safe and effective in humans, Moderna has said it could potentially deliver up to 1bn doses in 2021.

US biotech company Moderna has finished testing its Covid-19 vaccine candidate on monkeys, successfully protecting them against the virus.

The study involved giving two doses to 16 monkeys. Both injections were found to offer protection against coronavirus exposure and, encouragingly, the monkeys did not show any sign of vaccine-associated enhanced respiratory disease (VAERD), according to Moderna’s report published in the New England Journal of Medicine.

The company’s findings suggest the vaccine could protect humans against the virus in both the upper and lower airways.

Moderna’s vaccine acts by sending a viral messenger RNA (mRNA) into the body. This mRNA is used by the body’s cells to create a fragment of a SARS-CoV-2 viral particle that should not cause an infection, but is enough for the immune system to recognise as a foreign antigen.

MIT Technology Review noted that no other vaccine using messenger RNA has been successful in the past. If this one works, it will be “the first of its kind”.

Human trials

Moderna will now proceed to test the vaccine in a trial of 30,000 people. The next phase will determine its efficacy and safety and results are expected to surface in November or December of this year. Half of the people will get two injections of the vaccine 28 days apart and the other half will get two placebo injections of saltwater.

The study will be double blind. This means that nobody involved in it – participants or medical staff – will know who is getting the actual vaccine and who is getting the placebo shot.

If it is found to be safe and effective in humans, Moderna has said that it will be in a position to deliver 500m doses a year. This could grow to 1bn doses in 2021.

The New York Times lists other candidates for a Covid-19 vaccine, five of which are at the same stage as Moderna’s. The University of Oxford and AstraZeneca are testing their vaccine on people in England, Brazil and South Africa, while trials from other teams are taking place in the US, Argentina, Brazil, Germany, the United Arab Emirates and Australia.

Updated, 9.33am, 29 July 2020: This article has been updated to amend details on the vaccines currently at phase three trials.

Lisa Ardill was careers editor at Silicon Republic until June 2021