New, more contagious variants of the coronavirus are being investigated in the US, raising questions about whether the Covid vaccines currently in use offer protection against mutations.
There are several other contagious varieties around the world in the UK, South Africa and Brazil. In the United States, variants from New York City and California have been identified.
So far, studies suggest that the vaccines currently in use can recognize the emerging variants – but they don’t offer as much protection against these new strains. According to a February study, the variant from South Africa reduced Pfizer-BioNTech’s antibody protection by two thirds. Moderna’s neutralizing antibodies fell six-fold compared to the South African variant.
(There are several reasons why the antibodies generated after receiving a vaccine recognize but not fight a variant. For example, they protect antibodies by attaching to every single spike protein on the surface of the coronavirus, preventing it from happening Infecting your cell If a variant produces many times more viruses, the antibodies may not be able to attach themselves to all of these pieces of virus as precisely or efficiently.)
However, boosters and new versions of vaccines targeting the variants are already being studied.
The three emergency vaccines approved by the Food and Drug Administration from Moderna, Pfizer-BioNTech, and Johnson & Johnson work in different ways and therefore have different approaches to dealing with variants. Here’s what we know:
Moderna is testing a third dose of its existing vaccine as well as a booster shot that targets the South African variant. (Samples were sent to the National Institutes of Health for clinical trials on February 24th.)
Stephane Bancel, CEO of Moderna, said in a February 24 press release that the company “is committed to making as many updates as necessary to our vaccine until the pandemic is under control”.
Moderna’s vaccine uses messenger RNA or “mRNA” technology to deliver genetic material to cells with instructions on how to make a non-infectious piece of the coronavirus spike protein. The immune system recognizes the copies of the spike protein and makes antibodies against them. If a fully vaccinated person is exposed to the actual virus in the future, the body can remember how to trigger an immune response and how to make antibodies to the virus.
The new variant boosters use the same technology as Moderna’s original Covid vaccine. Bancel has said that the main thing is to “copy and paste” the new mutations into the vaccine. Dr. Kizzmekia Corbett, who led the team responsible for Moderna’s vaccine, calls this approach “plug and play”.
It can take months before clinical data can be verified and even longer before the boosters can be approved, manufactured and administered.
Stephen Hoge, president of Moderna, told Scientific American that if the variants start to dominate infections in the coming months, the company will be ready to “figure out when and how we switch”. Hoge did not comment on when the booster would be available.
Pfizer-BioNTech is also testing a third booster of its vaccine (which is an mRNA vaccine) in people who were fully vaccinated in the Phase 1 study. Participants will receive their third dose six to 12 months after being fully vaccinated.
The company is also discussing a clinical trial for “a variant-specific vaccine,” which a press release says is a reconstructed version of its original vaccine using the South African strain.
“We believe our vaccine is robust against all strains,” said Mizel Dolsten, Pfizer’s chief scientific officer, in an interview on Feb.25. In the future, it is “a reasonable possibility” that people need regular booster vaccinations, said Dolsten. Or companies may have to change pressures every few years to adapt, he said.
Like Moderna, Pfizer’s mRNA vaccine is quite adaptable.
“The flexibility of our proprietary mRNA vaccine platform enables us to technically develop booster vaccines on demand within weeks,” said Ugur Sahin, CEO and co-founder of BioNTech, in a press release.
“This regulatory pathway is already in place for other infectious diseases such as influenza. We are taking these steps to ensure long-term immunity to the virus and its variants.”
Johnson & Johnson
The latest vaccine to receive emergency approval from the Food and Drug Administration had a 72% effectiveness rate for preventing moderate disease in the United States. In South Africa, where a highly contagious mutation of the virus is the primary variant, its effectiveness was 64%, according to FDA data, it is effective in preventing moderate to severe or critical Covid. In Brazil, the vaccine was 66% effective.
(Experts say it’s worth noting that the Johnson & Johnson trials took place when the new variants had already become the dominant tribes in South Africa and Brazil, while the Moderna and Pfizer trials took place before.)
Johnson & Johnson’s single-dose vaccine uses adenovirus, a virus that causes colds, as a messenger to send instructions to cells in the body.
Alex Gorsky, CEO of Johnson & Johnson, said the company is well positioned to adapt the vaccine for variants and is working on developing software that “will help address some of these new and emerging variants” during one Interviews with CNBC’s “Squawk Box”. 1st March. He didn’t explain how the software would work.
“We are pretty confident that we will see a very robust response based on the clinical data we already have with our vaccine, but we are doing exactly the same thing at the same time [as other companies working on variants]”Said Gorsky.
Although Novavax’s two-shot Covid vaccine has not yet been approved in the United States, the company expects it will receive FDA approval by May.
Data from the UK study in January shows the vaccine was more than 89% effective against Covid and 85.6% effective against the UK variant. However, the Novavax vaccine was less than 50% effective in the South African strain.
Novavax is working on a third booster that could be tested in April, a company spokesman told Scientific American.
Novavax is a two-dose “sub-protein” vaccine, which means it contains harmless parts of the surface spike protein that trigger the immune system directly. In essence, scientists can add different strains to the existing vaccine as soon as variants appear.
Stanley Erck, CEO of Novavax, told NPR that the Covid vaccines are “very easy” to customize, much like how a flu vaccine is adjusted every year to match the known strains.
It could even be a “bivalent vaccine” that protects against multiple strains of the virus. “So we’re going to use the original Wuhan tribe and the South African tribe [to tweak the vaccine] and will likely test it on humans in the second quarter of this year, “Erck told NPR.
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