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How the different Covid vaccines handle new variants of the virus

New, more contagious variants of coronavirus are being studied in the United States, raising questions about whether current Covid vaccines will provide protection against mutations.

There are several more contagious varieties emerging all over the globe in the UK, South Africa and Brazil. In the United States, varieties from New York City and California have been identified.

So far, studies suggest that the vaccines currently in use may recognize the new variants ̵

1; but they do not provide as much protection against these new strains. The South African variant, for example, reduced Pfizer-BioNTech’s antibody protection by two-thirds, according to a February study. Modern neutralizing antibodies decreased 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 also fight it. Antibodies protect you by binding to each individual spike protein on the surface of the coronavirus, which prevents If a variant produces many times more virus, the antibodies may not be able to bind to all of these virus pieces as accurately or efficiently.)

But boosters and new versions of vaccines targeted at the variants are already being investigated.

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 handling varieties. Here’s what we know:


Moderna is testing using a third dose of its existing vaccine as well as using a booster shot targeted at the South African variant. (It sent samples to the National Institutes of Health for clinical trials on February 24.)

Modern CEO Stephane Bancel said the company “is committed to making as many updates to our vaccine as necessary until the pandemic is under control,” in a Feb. 24 press release.

Modern vaccine uses messenger RNA or “mRNA” technology to deliver genetic material to cells with instructions on how to make a non-infectious piece of coronavirus spike protein. The immune system recognizes the copies of the spike protein and creates antibodies against it. If a fully vaccinated person is exposed to the current virus in the future, the body can remember how to trigger 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 can take months before the clinical data is ready for review, and even longer before boosters are approved, produced and ready for administration.

Modern-day President Stephen Hoge told Scientific American that if the variants begin to dominate infections in the coming months, the company is ready to “find out when we switch and how.” Hoge did not comment on when the booster would be available.


Pfizer-BioNTech is also testing a third booster shot of its vaccine (which is an mRNA vaccine) on humans who were fully vaccinated in the Phase 1 study. Participants receive their third dose six to 12 months after being fully vaccinated, according to a release.

In addition, the company is discussing a clinical trial with “a variant-specific vaccine”, which is a reconstructed version of its original vaccine using the South African strain, according to a release.

“We think our vaccine is robustly active against all strains,” Pfizer’s scientific director Mikael Dolsten said in an interview on 25 February. In the future, it is “a reasonable option” that people will have to get regular booster shots, Dolsten said. Or companies may need to change the tribes every few years to adapt, he said.

Like Moderna, Pfizer’s mRNA vaccine is quite adaptable.

“The flexibility of our proprietary mRNA vaccine platform allows us to technically develop booster vaccines within a few weeks if needed,” said Ugur Sahin, CEO and co-founder of BioNTech, in a release.

“This regulatory pathway is already 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 for emergency use by the Food and Drug Administration, had an efficacy rate of 72% for the prevention of moderate illness in the United States. However, in South Africa, where a highly contagious mutation of the virus is the primary variant, the efficacy was 64% effective in preventing moderate to severe or critical Covid according to FDA data. In Brazil, the vaccine was 66% effective.

(Experts say it is worth noting that Johnson & Johnson’s trials took place as the new varieties had already become the dominant strains in South Africa and Brazil, while Modernas and Pfizer’s trials took place before that happened.)

Johnson & Johnson’s single-dose vaccine uses an adenovirus, a virus that causes colds, as a messenger to deliver instructions to the body’s cells.

Johnson & Johnson CEO Alex Gorsky said the company is well positioned to adapt the vaccine to variants and is working on developing software that will “help solve 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.

“We are quite sure, based on the clinical data we already have with our vaccine, 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.


Although Novavax’s Covid-to-shot vaccine has not yet been approved in the US, the company expects to receive FDA approval by May.

Data from the UK trial in January show that the vaccine was more than 89% effective in protecting against Covid and 85.6% effective against the UK variant. But 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 “protein subunit vaccine”, meaning that it contains harmless pieces of the surface girl protein that directly trigger the immune system. So, in essence, researchers can add different strains to the existing vaccine when variants arise.

Novavax CEO Stanley Erck told NPR that the Covid vaccines can be fine-tuned “very easily”, similar to how an influenza vaccine is adjusted each year to suit the prominent strains.

It may even end up being a “bivalent vaccine”, which is a vaccine that protects against multiple strains of a virus. “So we use the original Wuhan tribe and the South African tribe [to tweak the vaccine] and test it in humans probably in the second quarter of this year, ”Erck told NPR.

To check your eligibility status, use NBC News’ Schedule Your Vaccine Tool.

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