Novavax Inc.’s COVID-19 vaccine candidate showed strong efficacy against the coronavirus in a large trial that signals a new option is nearing for a global community still desperate for protection against the virus and its variants.

The shot was 90 per cent effective at preventing symptomatic COVID and 100 per cent effective at preventing moderate and severe symptoms, the U.S.-based biotech firm said in a statement on Monday. It was also 93 per cent effective against variants of concern, according to results from a secondary analysis that mostly included cases of the alpha variant predominant in the U.S.

The company plans to apply for regulatory clearance globally, with much of the first available doses going to low- and middle-income countries, Stanley Erck, Novavax’s chief executive officer, said on a conference call. The study results, which were at least as good as many analysts expected, suggest Novavax’s protein-based technology can be a rival to messenger RNA vaccines over time, especially if booster shots are needed.

“If you are going to stop this pandemic, you can’t just stop it in the U.S.,” Erck said in an interview Monday with David Westin on Bloomberg Television, calling his company’s shot particularly well suited to help with lower-income countries. “We can ship it at just standard refrigerated temperatures, and it can go anywhere in the world.”

The data “clearly position Novavax as a viable alternative to mRNA vaccines,” Kelechi Chikere, an analyst at Jefferies, wrote in a note to clients. Over time, Novavax’s vaccine could become a “universal booster” due to its high efficacy and low rate of side effects, Chikere said.

Novavax shares rose 1 per cent to US$211.74 at 12:50 p.m. in New York trading.

The vaccine is based on a recombinant protein technology, also used in the candidate developed by Sanofi and GlaxoSmithKline Plc. At over 90 per cent, the overall efficacy of the vaccine is similar to reported rates for messenger RNA shots developed by Pfizer Inc. with BioNTech SE and by Moderna Inc., as well as the Sputnik V vaccine from Russia, using viral vector technology.

Novavax’s phase 3 trial included almost 30,000 participants in the U.S. and Mexico. Side effects for the shot, given as a two-dose regimen taken 21 days apart, included headache, muscle pain and fatigue.

While the company didn’t provide exact numbers on the side effect rates, Erck said on Bloomberg Television that the shot will “have probably the most benign safety profile of any vaccine.”

Only one case of the highly contagious delta strain, which was first identified in India and remains rare in the U.S., was detected among trial participants, so the vaccine’s efficacy against it isn’t conclusive. And there were only two cases each of the beta and gamma variants detected in the trial so far.

Manufacturing capacity

The trick for Novavax will be ramping up production. The company is on track to reach manufacturing capacity of 100 million doses per month by the end of the third quarter and 150 million per month by the end of 2021. Still, it remains behind mRNA companies that have been in production for months.

While the U.S. has amassed enough doses of the Pfizer, Moderna and Johnson & Johnson shots to inoculate its population, other parts of the world have been slow to keep up. Novavax and its partners have arrangements to supply 1.1 billion doses of the vaccine to Covax, the World Health Organization-backed initiative aimed at providing fair access to vaccines for all countries.

”We look at this as a large ongoing market” akin to that of influenza vaccines, Erck said on the conference call.

U.S. use

In the U.S., the vaccine may be primarily used as a booster, Novavax executives said on the call and the Bloomberg Television interview, citing the vaccine’s low rate of side effects and ability to ship at refrigerator temperatures as potential advantages. Still, Pfizer, Moderna and J&J also have plans to produce boosters.

“The vast majority of our market” in the U.S. in the coming years will be booster shots, Erck told Bloomberg Television.

The new results were similar to results from a 15,000-person trial of the vaccine in the U.K. that was released in March, where the shot demonstrated 90 per cent effectiveness at preventing COVID symptoms across variants and the original version of the virus.