U.S. biotechnology firm Novavax Inc. said Thursday its experimental vaccine was about 89 percent effective in preventing the disease caused by the novel coronavirus during a late-stage clinical trial conducted in Britain.

The company also said in a press release the vaccine demonstrated "significant clinical efficacy" against both the rapidly emerging variants of the virus first identified in Britain and South Africa.

In this photo illustration the logo of Novavax is seen on the image of Coronavirus. (NurPhoto/Getty/Kyodo)

The phase three clinical trial in Britain, where a more contagious variant has been spreading, involved more than 15,000 participants between 18 and 84 years of age, including 27 percent over the age of 65.

Of the 62 cases diagnosed with COVID-19, the disease caused by the virus, six had received the vaccine and the rest had been administered a placebo, signaling an efficacy rate of 89.3 percent, the company based in Maryland said.

A preliminary analysis also indicated that the vaccine was 85.6 percent effective against the British strain.

Meanwhile, a mid-stage clinical trial in South Africa showed the vaccine was 60 percent effective among people who were HIV-negative.

In Japan, Takeda Pharmaceutical Co. is preparing to produce and sell a Novavax-developed vaccine.