AN Novavax’s Covid-19 vaccine proved almost 90% effective in preliminary results from a major clinical trial in the UK, the company said, but in a separate trial it appeared much less effective against a new variant of the coronavirus that was first identified in southern Africa.
In its test of 15,000 volunteers in the UK, Novavax said, the vaccine prevented nine out of 10 cases, including against a new strain of the virus that is circulating there. But in a study of 4,400 volunteers in South Africa, the vaccine was only 49% effective. In 94% of the study population who did not have HIV, the effectiveness was 60%.
In the UK study, Novavax observed 62 cases of symptomatic Covid-19, with 56 in the placebo group and six among the volunteers who received the vaccine. One placebo patient developed severe Covid-19, compared to zero in the vaccine group. The company provided few details about the safety of the vaccine, saying only that serious side effects were rare and balanced between the study vaccine and placebo groups.
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In the South African study, 29 cases of symptomatic Covid-19 were observed in the placebo group and 15 in the vaccine group.
It is not clear whether this data will be sufficient for US approval, or whether the US will wait for more data, as it appears to be doing with vaccines developed by AstraZeneca and the University of Oxford. Novavax said it hopes to apply for an emergency authorization in the UK in the coming months, once it has final data from its clinical trial there. The company said it was in contact with the Food and Drug Administration, but did not provide details about its plans.
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Operation Warp Speed, the United States government’s vaccine incubator, is conducting its own large Novavax vaccine trial in the United States and Mexico. The researchers hope to complete enrollment in the first half of February.
Carlos del Rio, professor of infectious diseases at Emory University School of Medicine, said the overall efficacy figures are impressive and that the vaccine showed at least some effectiveness against the variant first identified in South Africa.
Likewise, the least effective against this variant may be a vulnerability in the United States, where it was first reported in South Carolina on Thursday, and elsewhere.
Nahid Bhadelia, medical director of the special pathogen unit at the Boston Medical Center, emphasized that while the drop in effectiveness against the South African variant is bad news, the results are not “a complete wash”. The vaccine, she said, “can still make a big difference.” But the results also emphasize the important work of figuring out how to develop reinforcement shots against new variants, especially due to news that the South African strain, B1351, has been found in South Carolina.
Novavax said he is already working on a new version of the vaccine designed to combat more infectious strains of SARS-CoV-2, which could work as a booster injection for people already inoculated. But clinical tests are not expected until the second quarter of this year.
Some experts warned against over-interpreting the effectiveness results in the South Africa trial, noting that they totaled a relatively small number of cases in a preliminary analysis.
“I’m not sure if it is disappointing. The UK data looks very good. South Africa’s data may be more nuanced, ”said Anna Durbin, a professor at the Johns Hopkins Bloomberg School of Public Health, noting that each trial defined symptomatic disease slightly differently. She said she would be interested in seeing more data on the severity of the disease in the reported cases.
Scott Gottlieb, the former FDA commissioner and board member of Pfizer, said he did not think it was a surprise that the vaccine was less effective against the new strain.
“We have already seen experimentally that there is a drop in neutralization against this variant with the other vaccines, and we should expect this to be common to all vaccines that use the original spike protein as an epitope, regardless of how that protein is being delivered,” he said. .
More data will be available with the Johnson & Johnson results, expected soon, because this trial will include patients from Brazil and South Africa.
“I think it increases the risk of putting drivers in development based on these new variants and building a regulatory process that allows this type of incremental and subsequent innovation to reach the market based on something other than totally new and complete. exploding results studies, ”said Gottlieb.
Novavax data comes as countries around the world struggle to ensure sufficient vaccine doses to protect their populations. In the USA, the federal government has struggled to meet the demand for doses of the only two authorized vaccines, from Moderna and partners Pfizer and BioNTech.
Novavax said it expects to produce about 2 billion doses of its vaccine in 2021. The United States has signed a contract to buy 100 million of them and has the option to purchase more.
Like all Covid-19 vaccines that are being used or are in final testing, the injection of two doses of Novavax works by mimicking a protein called pico, which is found on the surface of SARS-CoV-2. When the immune system sees this protein, it produces antibodies against it, thus protecting the body from a case of Covid-19.
But Novavax is using the most tested and proven technology among the pioneers in the race to develop the Covid-19. The first two vaccines authorized in the United States use a technology called mRNA, which introduces genetic material into cells to create a protein that stimulates the immune system. Others still in development, like one from Johnson & Johnson and another from AstraZeneca, use genetically altered viruses to do something similar.
Like some approved vaccines, the Novavax vaccine makes fragments of the spike protein in insect cells and adds another chemical, called an adjuvant, to stimulate the immune system to respond. This approach is used in an approved flu vaccine sold by Sanofi and was the approach that Sanofi and GlaxoSmithKline planned to use in their own Covid-19 vaccine.
The similarities are not entirely coincidental. Gale Smith, the former scientific director of the company that developed the vaccine, is now a scientist at Novavax. But as the drug giants stumbled, Novavax, a small company that had not yet launched a product on the market, mainly achieved its goals.
The company presented promising data in early August that showed neutralizing antibody levels that were almost quadruple those seen in patients who recovered from Covid-19, among the best for any vaccine in the first tests. These same results were published in the New England Journal of Medicine in September.
In July, Novavax received $ 1.6 billion in financing Operation Warp Speed to expand its manufacturing processes, with the agreement that the resulting 100 million doses of vaccine would be owned by the United States government.