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Washington – U.S. biotech firm Novavax said on Thursday its two-dose COVID-19 vaccine showed a 89.3% efficiency in a major Phase 3 clinical trial in Britain and remained highly effective against a variant first identified there. But the positive news was offset somewhat by other results which showed that it offered less protection against a highly transmissible variant of the Corona virus first identified in South Africa.
Like the British strain, the variant first found in South Africa is now spreading rapidly around the world, and the first cases have been confirmed in the United States. In recent weeks, vaccines developed around the world may be less effective against the virus. South African variant in particular, and although the results of the Novavax trial appear to confirm some level of resistance, the company and an external health expert were optimistic about the level of protection provided against the two new strains.
“NVX-CoV2373 has the potential to play an important role in addressing this global public health crisis,” said company president and CEO Stanley Erck, using the Novavax name for the vaccine. “We look forward to continuing to work with our partners, collaborators, researchers and regulators around the world to make the vaccine available as quickly as possible.”
British Prime Minister Boris Johnson tweeted that the results were “good news”, adding that British drug regulators would now be evaluating the vaccine for potential approval.
The vaccine was one of six candidates backed by a US government project formerly known as Operation Warp Speed, which provided the Maryland-based company with $ 1.75 billion. It is also being tested in a trial in the United States and Mexico, which has so far recruited around 16,000 out of 30,000 participants.
Unlike the Pfizer, Moderna, and AstraZeneca vaccines, which provide the genetic instructions for human cells to create a key virus protein, the Novavax vaccine injects the proteins directly into the body to elicit an immune response.
“Fairly good” against South African strain
The UK trial involved 15,000 people between the ages of 18 and 84, 27% of whom were over 65. The first interim analysis was based on 62 confirmed COVID-19 cases among the participants, of which 56 cases were seen in the placebo group versus six cases among those who received the vaccine.
The company’s preliminary analysis indicated that the variant first identified in the UK, called B.1.1.7, has been detected in more than 50% of confirmed cases. Novavax said the results showed their vaccine was 95.6% effective against the original COVID-19 strain and 85.6% against the UK variant.
But the level of protection was lower in a smaller mid-term trial in South Africa. This study recruited just over 4,400 patients from September to mid-January, during which time the B.1.351 variant, which contains critical mutations along the virus spike protein, was spreading rapidly across the country.
The overall efficacy was 49.4% in this trial, but this figure rose to 60% among the 94% of trial participants who were HIV negative.
Worryingly, Novavax said about one-third of trial participants in South Africa had already been infected with the original form of the virus, while subsequent infections during the study largely came from the variant. .
The results come just days after South African researchers told CBS News the new strain in the country emerged very resistant to antibodies in blood samples from people infected with the original strain of the virus, first detected in Wuhan, China at the end of 2019. vaccine effectiveness.
Amesh Adalja, a doctor and senior researcher at the Johns Hopkins Center for Health Security, however, told AFP that it was important to keep the declining efficacy in perspective and that the vaccine was always a success.
“Sixty percent against the variant is still pretty good,” he said. “Obviously, the Novavax vaccine prevented serious illness, which is really what matters most.”
Professor Shabir Madhi, who heads the South African trials, said Thursday evening that Novavax’s results were something “he didn’t dream about” when he saw how natural immunity was from the first wave of infections COVID, along with the original strain, was unfavorable. the variant in South Africa.
Novavax CEO Erck called the preliminary results of the trial’s effectiveness in South Africa “above people’s expectations.”
Studies in Britain and South Africa were the first to assess the performance of a COVID-19 vaccine against British and South African variants in real-world trials.
Moderna has already said that his the vaccine “should” remain effective against the two new highly infectious variants, but the cited study was based on laboratory research and not real-world testing against human infection.
Pfizer also has reported laboratory results who suggest his vaccine will prove effective against the British variant, but has yet to reveal data for testing against the strain prevalent in South Africa.
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