Washington – US biotechnology company Novavax said on Thursday that its two-shot COVID-19 vaccine showed a total 89.3% efficiency in a major phase 3 clinical trial in Britain and continued to be highly effective against a variant that was first identified. But the positive news was offset somewhat by other results that showed it offered less protection against a highly transmissible variant of the Crown virus first identified in South Africa.
Like the UK strain, the variant first found in South Africa is spreading rapidly around the world and the first cases have been confirmed in the US. In recent weeks there has been concern that vaccines developed around the world are less effective against the South African variant in particular, and while the results of the Novavax trial seem to confirm a certain level of resistance, both the company as 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 resolving this global public health crisis,” said Stanley Erck, president and CEO of the company, 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 has tweeted that the results were “good news”, adding that UK drug regulators would now evaluate the vaccine for possible approval.
The vaccine was one of six candidates backed by a U.S. 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 recruited up to 16,000 of 30,000 participants so far.
Unlike the Pfizer, Moderna, and AstraZeneca vaccines, which provide genetic instructions that cause human cells to create a key protein in the virus, the Novavax trait injects proteins directly into the body to elicit an immune response.
“Pretty good” against the South African strain
The British trial involved 15,000 people aged 18 to 84, including 27% over the age of 65. The first interim analysis was based on 62 cases of confirmed COVID-19 among participants, of which 56 cases were observed in the placebo group versus six cases among people who received the vaccine.
Preliminary analysis of the company indicated that the variant first identified in the UK, called B.1.1.7, was detected in more than 50% of confirmed cases. Novavax said the results showed that its 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-stage trial in South Africa. This study included just over 4,400 patients from September to mid-January, a period during which variant B.1.351, which contains critical mutations along the virus’s peak protein, spread rapidly across the country.
Overall efficacy was 49.4% in this trial, but this figure increased to 60% among 94% of trial participants who were HIV negative.
Of concern, Novavax said about a third of trial participants in South Africa had been previously infected with the original form of the virus, while subsequent infections during the study were largely of the variant.
The results come just days after South African investigators told CBS News that the new strain appeared in the country highly resistant to antibodies in blood samples from people infected with the original strain of the virus, first detected in Wuhan (China) in late 2019. That research left scientists worried that the previous infection might provide little immunity to the new variant of South- Africa and vaccine efficacy.
Amesh Adalja, a doctor and senior academic at the Johns Hopkins Center for Health Security, told AFP, however, that it was important to keep the decline in effectiveness in perspective and that the vaccine was still a success.
“Sixty percent against the variant is still pretty good,” he said. “It’s clear that the Novavax vaccine prevented serious illness, which in the end is what matters most.”
Professor Shabir Madhi, who is leading the South African trials, said on Thursday evening that the results of Novavax were something he “did not dream of” when he saw the natural immunity of the first wave of COVID infections, with the original strain, the variant in South Africa was badly found.
Novavax CEO Erck described 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 evaluate the performance of a COVID-19 vaccine against UK and South African variants in real-world trials.
Modern has previously said that his the vaccine “should” be effective against the two new highly infectious variants, but the study he cited was based on laboratory research, not actual testing against human infection.
Pfizer has too reported laboratory results suggesting that his vaccine will be effective against the UK variant, but he has not yet revealed any evidence to test against the strain prevalent in South Africa.