A new Covid-19 vaccine from Novavax Inc. was effective in big trials in the U.K. and South Africa, though its protective power appeared to be reduced in South Africa, where a worrisome mutation is prevalent.
The results indicated that another highly potent vaccine could soon be available to help ameliorate the pandemic, in addition to existing vaccines from Pfizer Inc., Moderna Inc., and AstraZeneca Plc that are authorized in various countries. But the South Africa results also suggested that the virus is starting to mutate in ways that could make vaccines less effective over time.
Shares of Novavax rose 30% in premarket trading Friday.
Novavax said its vaccine met its primary endpoint in a final-stage study on more than 15,000 people in the U.K., proving to be 89.3% effective in preventing symptomatic Covid-19. The result was based on an interim analysis of 62 cases, of which 56 were in the placebo group and only 6 in people who had got the vaccine.
The trial found the vaccine remained effective against the more transmissible B.1.1.7 strain that is common there. There was a low level of significant adverse events, the company said.
Good news that the @Novavax vaccine has proved effective in UK trials. Thank you to all the volunteers who made these results possible.
Our medicines regulator will now assess the vaccine, which will be made in Teesside. If approved, we have 60m doses on order.— Boris Johnson (@BorisJohnson) January 28, 2021
Unlike other new vaccines that induce human cells to make viral proteins, the Novavax vaccine itself mimics portions of the spike protein that the coronavirus uses to enter cells. It also includes an adjuvant, a component that boosts the immune response.
The trial results could soon put the vaccine on a path to authorization in multiple countries. Novavax is backed by $1.6 billion in funding from the U.S. government under a deal for 100 million doses, and the U.K. is set to get 60 million doses. British Prime Minister Boris Johnson said on Twitter that officials there are ready to review the vaccine.
The vaccine was somewhat less effective in a second trial in South Africa, where a worrisome variant called B.1.351 is prevalent. This variant contains mutations in the spike protein that change its shape and may make it harder for antibodies to recognize it.
In the South Africa trial of over 4,400 people, the vaccine was 60% effective in the vast majority of people that were HIV negative, Novavax said in a statement. It was 49.4% effective overall, when HIV positive patients were also counted.
Most cases of the virus seen in the trial had the new South Africa mutation, the company said.
What Bloomberg Intelligence Says:
“Novavax’s U.K. Covid-19-vaccine Phase III trial — the first test against the new B.1.1.7 variant — produced a good result with high efficacy, though just 60% efficacy against the South African B.1.351 variant is a concern.”
— Sam Fazeli, pharma analyst
Novavax S. African Data a Concern, Despite Vaccine Acing in U.K.
Novavax is also conducting a large federally funded trial in the U.S. and Mexico. It has enrolled 16,000 people to date, and the company expects to complete enrollment of all 30,000 people in mid-February, it said in a statement.
It’s not yet clear whether the company would seek U.S. emergency authorization to distribute the vaccine based on the U.K. and South Africa trials, or whether it would wait for data from the U.S.-Mexico trial first. AstraZeneca hasn’t yet sought U.S. clearance for its vaccine while it waits for data from a U.S. trial.
Meanwhile, the company has already started working on new vaccine constructs against the emerging strains and expects to choose candidates for a booster shot or combination vaccine in the coming days, it said.
