Moderna vaccine found highly effective against Covid-19

Moderna Inc. said its Covid-19 vaccine was 94.5% effective in a preliminary analysis of a large late-stage clinical trial, another sign that a fast-paced hunt by scientists and pharmaceutical companies is paying off with potent new tools that could help control a worsening pandemic.

The highly positive readout comes just a week after a similar shot developed by Pfizer Inc., and BioNTech SE was found to be more than 90% effective in an interim analysis. Both shots rely on a technology called messenger RNA that has never been used to build an approved vaccine. Soon, millions of people around the world could be spared from illness by the breakthroughs.

A preliminary analysis of data from more than 30,000 volunteers showed Moderna's vaccine prevented virtually all symptomatic cases of Covid-19, the disease caused by the coronavirus, the company said in a statement on Monday.

Moderna shares rose 12% in pre-market U.S. trading, while in Europe, the Stoxx 600 Index was up 1.4%. The rally in global shares following the news represented about $120 billion in market value added to the MSCI All Country World Index.

Only five participants who received two doses of the vaccine became sick, compared with 90 coronavirus cases in participants who received a placebo, according to a review by an independent data safety monitoring board appointed by the U.S. National Institutes of Health.

The vaccine also appeared to be effective in preventing the most severe Covid-19 infections. According to Moderna's statement, there were no severe cases among people who got the vaccine, compared with 11 in volunteers who received placebo shots.

Once a vaccine is cleared, distribution is expected to be a significant challenge. Handling some of the shots that are being studied is complicated: For example, Pfizer's must be stored at ultra-cold temperatures until a few days before it is used, a requirement that adds logistical hurdles for states that will be in charge of overseeing the inoculation effort.

Moderna said on Monday that new stability data showed its vaccine is stable at refrigerator temperatures for 30 days, much longer than a previously estimated seven days. It can be kept in freezers for longer-term storage, though it doesn't need the Pfizer vaccine's unique facilities.

Both the Moderna vaccine and Pfizer's based on mRNA technology designed to transform the body's cells into vaccine making factories. Once injected, the vaccines instruct cells to make copies of the coronavirus's spike protein, stimulating the creation of protective antibodies.