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COVID-19 vaccines work well against the California variant



As the California coronavirus variant continues to spread across the Golden State and beyond, new research suggests that more vaccines should continue to provide an effective defense against it.

The results, published Wednesday in the New England Journal of Medicine, provide good reason for Californians to continue rolling up their sleeves as the vaccination campaign catches steam across the state.

“We do not expect this variant to be a problem for the vaccines – so that’s really good news,”

; said study leader David Montefiori, a virologist at Duke University.

The California variant is actually a pair of closely related fellow travelers known as B.1.427 and B.1.429. Researchers say they most likely emerged in the state in May and then rose to become the dominant tribe in the midst of the deadly holiday wave.

They accounted for 56% of the samples from California, which were genetically sequenced between February 28 and March 13, according to the Centers for Disease Control and Prevention. They have appeared in every state and District of Columbia and have spread as far as Australia, Singapore, Israel and Denmark.

The California tribe is just one of several so-called variants of concern tracked by the CDC. Others include B.1.1.7, from the United Kingdom, the P.1 variant from Brazil and the B.1.351 variant from South Africa. They threaten because they are more transmissible, more virulent, or more resistant to vaccines than their predecessors.

Researchers and public health officials aim to eliminate these variants by vaccinating the population as soon as possible. Not only will it prevent their spread, but it deprives them of the opportunity to get new mutations that can make them even more dangerous.

Since these coronavirus variants have emerged and spread far beyond their places of origin, they have raised concerns about whether the current crop of vaccines will effectively protect against them. This is because the variants have acquired genetic mutations that affect the spike protein that the virus uses to penetrate and invade human cells – and which the vaccines use as a target.

The fear is that the mutations may alter the spike protein so much that an immune system trained to recognize an earlier version of the virus could not recognize a variant and leave a vaccinated person without biological defense.

So a team of researchers decided to try two vaccines.

They tested blood samples from people who had received the COVID-19 vaccine developed by Moderna or a vaccine candidate from Novavax not yet approved for use in the United States. They then introduced the manipulated versions of viral variants to these blood samples, waiting to see what kind of immune system response they elicited.

The dominant strain in the United States is called D614G, and it was neutralized by blood from people who received one of the vaccines.

The California variant they tested, B.1.429, was slightly less susceptible to both the Moderna and Novavax vaccines, but both shots still generated effective protection, the researchers found. This is because the body generates far higher antibody levels than are actually needed to neutralize the virus, Montefiori said.

And while the Pfizer BioNTech vaccine was not tested in this paper, it would likely work just as well as the Moderna vaccine, as both use similar technology, he said.

“People in Los Angeles can feel very good about getting the current vaccines – that they will be just as protected by these vaccines as people living in areas where they do not have the California variant,” Montefiori said.

“It’s always nice to get that type of result,” he added.

But with both vaccines, there was a marked drop in performance against the South African variant.

These laboratory results were not ideal, but they were not exactly a surprise. In clinical trials, the Novavax vaccine was 89% effective in the United Kingdom, but only 49% effective in South Africa, where B.1.351 predominates.

Similarly, the Johnson & Johnson vaccine, which reduced the risk of moderate to severe disease by 72% when tested in the United States, was only 57% effective in South Africa. And a vaccine developed by AstraZeneca and Oxford University did not work better than placebo when tested in a South African clinical trial.

The new paper was one of several published in the New England Journal of Medicine on Wednesday about viral variants and vaccines.

A team of South African researchers testing blood plasma from patients who had been infected with the South African variant reported that their antibodies still provided a significant level of protection against the “original” version of the coronavirus as well as the Brazilian strain.

The result: Vaccines designed to target the B.1.351 version of the spike protein may be effective against a variety of variants, the researchers suggested.

In another paper, researchers in Israel examined the antibody responses in blood samples from six health workers who had become infected and later received a dose of the Pfizer vaccine. They found that after vaccination their immune system turned against the original virus and the British, Brazilian and South African variants with antibody responses that were 114, 203, 81 and 228 times as high as just before their shots, respectively.

“This underscores the importance of vaccination even in previously infected patients given the added benefit of an increased antibody response to the tested variants,” the researchers wrote.

The South African variant may raise concerns about vaccine resistance, but so far it has done little more than establish a foothold in the United States, Montefiori said. According to the CDC, there have been 386 confirmed cases involving B.1.351 as of Tuesday compared to 16,275 involving the UK variant.

It is important to keep in mind that this type of test does not measure the full degree of protection that a vaccine provides in an actual person, said Dr. Monica Gandhi, an infectious disease expert at UC San Francisco who was not involved in the new research. .

For example, these tests look at antibodies, but not T cells, which form another important arm in the immune system’s defenses.

“This is a laboratory test,” Gandhi said. “This does not tell us in real life whether these vaccines will not be able to elicit enough T cells, which are super difficult to measure, to kill the South African virus.”

John Moore, a virologist at Weill Cornell Medical College who was not involved in the new work, agreed.

There is only so much that can be extrapolated from the immune response seen in blood tests, but a study like this provides useful clues “as to whether different variants are or probably are not a problem for vaccines,” Moore said. “It’s a guide.”




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