In the United States, research is being done on new, more contagious variants of the coronavirus, which raises the question of whether the current Covid vaccines offer protection against mutations.
Multiple, more contagious varieties are emerging around the world, in the United Kingdom, South Africa and Brazil. In the US, 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. For example, the South African variant reduced Pfizer-BioNTech’s antibody protection by two-thirds, according to a February study. The Moderna neutralizing antibodies are six-fold with the South African variant.
(There are several reasons why the antibodies generated after receiving a vaccine may recognize a variant, but not fight it. Antibodies protect you by attaching to each individual spike protein on the surface of the coronavirus, making it cannot infect your cell.Variant produces many times more virus, the antibodies may not be able to attach to all those virus pieces as accurately or efficiently.)
But boosters and new versions of vaccines targeting the variants are already being explored.
The three vaccines approved by the Food and Drug Administration for emergency use from Moderna, Pfizer-BioNTech, and Johnson & Johnson work in different ways and therefore have different approaches to dealing with variants. This is what we know:
Modern
Moderna is testing using a third dose of its existing vaccine, as well as a booster shot targeting the South African variant. (It sent samples to the National Institutes of Health for clinical trials on Feb. 24.)
Moderna’s CEO Stephane Bancel said the company is “committed to making as many updates to our vaccine as possible until the pandemic is under control,” in a Feb. 24 press release.
Moderna’s vaccine uses messenger RNA or “mRNA” technology to deliver genetic material to cells with instructions for making a non-infectious piece of the coronavirus spike protein. The immune system recognizes the copies of the spike protein and makes antibodies against it. If a fully vaccinated person is exposed to the actual virus in the future, the body can remember how to activate an immune response and create antibodies that fight the virus.
The boosters for new variants use the same technology as Moderna’s original Covid vaccine. Bancel has said it is essentially a matter of “copying and pasting” 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 may take months for the clinical data to be ready for assessment, and even longer for the boosters to be approved, manufactured and ready to be administered.
Moderna president Stephen Hoge told Scientific American that if the variants start to dominate infections in the coming months, the company is willing to “find out when we switch and how.” Hoge did not comment on when the booster would be available.
Pfizer-BioNTech
Pfizer-BioNTech is also testing a third booster shot of its vaccine (which is an mRNA vaccine) on people fully vaccinated in the phase 1 study. Participants will receive their third dose six to 12 months after they are fully vaccinated, according to a release.
In addition, the company is discussing a clinical trial for “a variant-specific vaccine” which is a reconstructed version of the original vaccine using the strain from South Africa, according to a release.
“We believe our vaccine is potent against all species,” Mikael Dolsten, Pfizer’s Chief Scientific Officer, said in an interview on Feb. 25. In the future, it’s “a reasonable possibility” that people will need regular booster shots, Dolsten said. Or maybe the companies need to change the tribes every few years to adapt, he said.
Like Moderna, Pfizer’s mRNA vaccine is quite customizable.
“The flexibility of our proprietary mRNA vaccine platform allows us to technically develop booster vaccines within weeks if needed,” said Ugur Sahin, CEO and co-founder of BioNTech in a press release.
“This regulatory pathway has already been established 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 approved by the Food and Drug Administration for emergency use had a 72% efficacy rate for preventing moderate disease in the U.S. But in South Africa, where a highly contagious mutation of the virus is the primary variant effectiveness, according to FDA data, was 64% 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 strains in South Africa and Brazil, while the Moderna and Pfizer trials happened before that happened.)
The single-dose vaccine from Johnson & Johnson uses an adenovirus, a virus that causes the common cold, as a messenger to give instructions to the body’s cells.
Alex Gorsky, CEO of Johnson & Johnson, said the company is well positioned to customize the vaccine for variants and is developing software that “will help address some of these new and emerging variants,” during an interview with CNBC’s “Squawk Box”. March 1. He did not explain how the software would work.
Based on the clinical data we already have with our vaccine, we are confident that we will see a very robust response, but at the same time we are doing exactly the same [as other companies working on variants], ‘Said Gorsky.
Novavax
Although the Covid vaccine containing two injections of Novavax has not yet been approved in the US, the company expects it to receive FDA approval in May.
Data from the UK trial in January shows that the vaccine was more than 89% effective at protecting against Covid and 85.6% against the UK variant. But the Novavax vaccine was less than 50% effective against the South African strain.
Novavax is working on a third booster that could be tested in April, a company spokesperson told Scientific American.
Novavax is a two-dose “protein subunit vaccine”, which means that it contains harmless pieces of the protein on the surface that directly activate the immune system. So, essentially, scientists can add different strains to the existing vaccine if variants emerge.
Novavax CEO Stanley Erck told NPR that the Covid vaccines can be “very easily” adapted, similar to how a flu vaccine is adapted to the prominent strains every year.
It could even become a ‘bivalent vaccine’, a vaccine that protects against different strains of virus. So we will use the original Wuhan kind and the South African kind [to tweak the vaccine] and probably testing it in humans in the second quarter of this year, “Erck told NPR.
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