Novavax Inc said on Thursday its coronavirus vaccine was 89.3% effective in preventing COVID-19 in a trial conducted in the United Kingdom, and was nearly as effective in protecting against the more highly contagious variant first discovered in the UK, according to a preliminary analysis.
A mid-stage trial of the vaccine in South Africa, where a potent variant of the virus is common, showed 60% effectiveness among people who did not have HIV.
Novavax shares rose more than 22% in after hours trading following the report, which comes on the day the United States reported its first cases of the South African variant.
Novavax said the UK trial, which enrolled 15 000 people aged 18 to 84, is expected to be used to apply for regulatory review in Britain, the European Union and other countries.
Some 27% of people in the trial are over age 65.
The study took place as the more highly transmissible UK variant was circulating, and the preliminary analysis suggests the vaccine was 85.6% effective against this mutation, the U.S. company announced in a news release. It did not provide the study data.
In the UK trial, the effectiveness of the vaccine was close to that of the two authorized vaccines from Pfizer Inc /BioNTech SE and Moderna Inc, whose two-dose regimens were around 95% effective at preventing COVID-19 in clinical trials.
John Moore, a professor of microbiology and immunology at Weill Cornell Medical College in New York, said the UK data are essential the same as those shown by Pfizer and Moderna.
“It’s not statistically different. The vaccine basically works well in the predominant strain circulating in the UK, which means it’s like to be equally effective in the United States,” he said.
“The South African variant is clearly going to be an issue, but it’s not an absolutely catastrophic event either. The key thing is to stop this variant from spreading,” Moore added.
The South African variant has been shown to evade antibody protection in lab studies by Moderna Inc and Pfizer Inc and BioNTech.
“The 60% reduced risk against COVID-19 illness in vaccinated individuals in South Africans underscores the value of this vaccine to prevent illness from the highly worrisome variant currently circulating in South Africa, and which is spreading globally,” Professor Shabir Maddi, lead investigator of the Novavax vaccine trial in South Africa.
Novavax said it started making new versions of its vaccine to protect against emerging virus variants in early January and expects to select ideal candidates for a booster in the coming days. The company said it plans to initiate clinical testing of these new vaccines in the second quarter of this year.
