Novavax Says Vaccine 89.3 Percent Effective in UK Trial, Less in South Africa

January 28, 2021 Updated: January 29, 2021

Novavax announced that its vaccine against the CCP virus was shown to be 89.3 percent effective in preventing the COVID-19 disease in a trial in the United Kingdom, but less effective in South Africa where a different virus variant is more prevalent.

“Strong efficacy in Phase 3 UK trial with over 50 % of cases attributable to the now-predominant UK variant and the remainder attributable to COVID-19 virus,” the company announced on its website.

The company on a conference call noted that this was interim data, and executives said they expect it will be two to three months before they are ready to apply for authorization with regulators in Britain, the European Union, and other countries.

UK Prime Minister Boris Johnson said that if the vaccine is approved, there will be 60 million cases on order.

The trial, which is still underway, enrolled more than 15,000 people aged 18 to 84, including 27 percent over 65.

The study findings are based on cases that occurred at least a week after the second vaccine dose. The first interim analysis found that 62 people so far have been diagnosed with COVID-19 of which only six in the group received the vaccine, with the rest receiving a placebo. Researchers found a “point estimate of vaccine efficacy of 89.3 % (95 % CI: 75.2–95.4).”

“Of the 62 cases, 61 were mild or moderate, and 1 was severe (in placebo group),” the company noted. It added that preliminary analysis indicates that 32 of the 62 cases were the UK variant strain of the CCP (Chinese Communist Party) virus.

Novavax said that the vaccine is about 95.6 percent effective against the non-variant or the older CCP virus, and 85.6 percent effective against the new UK variant.

“Both those numbers are dramatic demonstrations of the ability of our vaccine to develop a very potent immune response,” Novavax CEO Stanley Erck said in a call with investors late Thursday.

Less Efficacy in South Africa

Meanwhile, results from a smaller study in South Africa suggests the vaccine does work but not nearly as well as it does against the UK variant.

The study administered the vaccine to 15 people of 44 people who contracted COVID-19. Genetic testing is still underway, however preliminary data on 27 of the 44 cases showed that 92.6 percent (25 out of 27) had the new South African CCP virus variant, which carries different mutations.

The vaccine in the South Africa trial is showing about 60 percent effectiveness among those who were HIV-negative, the company announced. Including volunteers with HIV, overall the protection was 49 percent.

More concerning is what the study showed about a totally different question—the chances of people getting COVID-19 a second time, said the leader of the South African study, Shabir Madhi of the University of the Witwatersrand in Johannesburg.

Tests suggested that nearly a third of study participants had been previously infected, yet rates of new infections in the placebo group were similar.

“These data suggest that prior infection with COVID-19 may not completely protect against subsequent infection by the South Africa escape variant,” the company announced, asserting that vaccination with its vaccine, in contrast, “provided significant protection.”

Reuters and The Associated press contributed to this report.

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