How Different Covid Vaccines Will Handle New Virus Variants


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

Multiple, more contagious variants are emerging around the world, in the UK, South Africa and Brazil. In the US, New York City and California variants have been identified.

So far, studies suggest that vaccines currently in use may recognize emerging variants, but 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. Moderna neutralizing antibodies were reduced six-fold with the South African variant.

(There are several reasons why antibodies generated after receiving a vaccine may recognize a variant but not fight it as well. Antibodies protect you by attaching to each individual spike protein on the surface of the coronavirus, preventing it from infecting your cell. variant produces many times more virus, antibodies may not be able to adhere to all of these virus fragments with as much precision or efficiency).

But boosters and new versions of vaccines that target the variants are already being explored.

The three vaccines that have been licensed 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 managing variants. This is what we know:

Modern

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

Moderna 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 February 24 press release.

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 copies of the spike protein and creates antibodies against it. If a fully vaccinated person is exposed to the real virus in the future, the body can remember how to trigger an immune response and create antibodies that fight the virus.

The boosters for the new variants use the same technology as Moderna’s original Covid vaccine. Bancel has said that it is essentially “copy and paste” the new mutations in the vaccine. Dr. Kizzmekia Corbett, who led Moderna’s vaccine team, calls this approach “plug and play.”

It can take months for clinical data to be ready for review, and even longer for boosters to be approved, produced, and ready to be administered.

Moderna president Stephen Hoge told Scientific American that if variants begin to dominate infections in the coming months, the company is prepared to “find out when and how we change.” Hoge did not comment on when the booster would be available.

Pfizer-BioNTech

Pfizer-BioNTech is also testing a third booster injection 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, according to a statement.

In addition, the company is discussing a clinical trial for “a specific variant vaccine” that is a rebuilt version of its original vaccine using the South African strain, according to a statement.

“We believe that our vaccine is very active against all strains,” said Pfizer Chief Scientific Officer Mikael Dolsten in an interview on February 25. In the future, it is “a reasonable possibility” that people will need regular booster shots, Dolsten said. Or companies may need to change stresses 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 in a matter of weeks, if necessary,” Ugur Sahin, CEO and co-founder of BioNTech, said in a statement.

“This regulatory pathway is already established for other infectious diseases such as influenza. We take these steps to ensure long-term immunity against the virus and its variants.”

Johnson and Johnson

The newest vaccine to gain emergency use authorization from the Food and Drug Administration had a 72% efficacy rate in preventing moderate illness in the U.S. But in South Africa, where a highly contagious mutation of the virus is Primary variant, effectiveness was 64% effective in preventing moderate to severe or critical Covid, based on FDA data. In Brazil, the vaccine was 66% effective.

(Experts say it is worth noting that the Johnson & Johnson trials were conducted when the new variants had already become the dominant strains in South Africa and Brazil, while the Moderna and Pfizer trials took place before that happened).

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

Johnson & Johnson CEO Alex Gorsky said the company is well positioned to tailor the vaccine to the variants and is working on developing software that will “help address some of these new and emerging variants,” during an interview. with CNBC’s “Squawk Box.” March 1st. He did not explain how the software would work.

“Based on the clinical data that we already have with our vaccine, we are quite confident that we will see a very robust response, but at the same time we are doing the exact same thing. [as other companies working on variants]”Gorsky said.

Novavax

Although Novavax’s two-shot Covid vaccine is not yet approved in the US, the company expects it to get FDA approval in May.

Data from the UK trial in January shows 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 spokesperson told Scientific American.

Novavax is a two-dose “protein subunit vaccine,” which means that it contains harmless parts of the surface protein that directly triggers the immune system. So essentially, scientists can add different strains to the existing vaccine as variants emerge.

Novavax CEO Stanley Erck told NPR that Covid vaccines can be modified “very easily,” similar to how a flu vaccine is adjusted each year to accommodate prominent strains.

It could even end up as a “bivalent vaccine,” which is a vaccine that protects against various strains of a virus. “So we will use the original Wuhan strain and the South African strain. [to tweak the vaccine] and testing it in humans probably in the second quarter of this year, “Erck told NPR.

To check your eligibility status, you can use the NBC News plan, your vaccination tool.

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