As the California coronavirus variant continues to spread in the Golden State and beyond, new research suggests that several vaccines should continue to provide an effective defense against it.
The results, published Wednesday in the New England Journal of Medicine, offer good reason for Californians to continue to roll up their sleeves as the vaccination campaign gains momentum across the state.
12:40 pm, 08 April 2021A previous version of this article reported that Johnson & Johnson’s COVID-19 vaccine was 57% effective in preventing moderate to severe illness when tested in South Africa. This figure was exceeded; the J&J vaccine is 64% effective in South Africa.
“We don’t expect this variant to pose a problem for vaccines – so that’s very good news,” said study leader David Montefiori, virologist at Duke University.
The California variant is actually a pair of closely related travel companions known as B.1.427 and B.1.429. Scientists say they likely appeared in the state in May and then became the dominant strain amid the deadly wave of the holidays.
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They represented 56% of samples from California that were genetically sequenced between February 28 and March 13, according to the Centers for Disease Control and Prevention. They appeared in all states and the District of Columbia, and spread to Australia, Singapore, Israel and Denmark.
The California strain is just one of many so-called worrying variants tracked by the CDC. Others include B.1.1.7, from the UK, variant P.1 from Brazil, and variant B.1.351 from South Africa. They are threatening because they are more transmissible, more virulent or more resistant to vaccines than their predecessors.
Scientists and public health officials aim to crush these variants by vaccinating the population as quickly as possible. Not only will this hinder their spread, but it will deprive them of opportunities to acquire new mutations that could make them even more dangerous.
As these coronavirus variants have emerged and spread far beyond their places of origin, they have expressed concerns about whether the current crop of vaccines will effectively protect them. This is because the variants have acquired genetic mutations that affect the spike protein, which the virus uses to enter and invade human cells – and which vaccines use as a target.
The fear is that mutations could alter the spike protein so much that an immune system trained to recognize an earlier version of the virus would fail to recognize a variant, leaving a vaccinated person without any biological defense.
A team of researchers therefore decided to test two vaccines.
They used blood samples from people who received the COVID-19 vaccine developed by Moderna or a candidate vaccine from Novavax that has not yet been approved for use in the United States. Then they introduced technical versions of viral variants to those blood samples and waited to see how many infectious viruses survived.
The dominant strain in the United States is called D614G, and it has been neutralized by the blood of people who have received either vaccine.
The California variant they tested, B.1.429, was somewhat less sensitive to Moderna and Novavax vaccines, but both vaccines still generated effective protection, the researchers found. This is because the body generates much higher levels of antibodies than is actually needed to neutralize the virus, Montefiori said.
And although the Pfizer-BioNTech vaccine was not studied in this article, it would likely work as well as the Moderna vaccine, as both use similar technology, he said.
“People in Los Angeles can feel very happy to receive the current vaccines – that they’re going to be just as protected by these vaccines as people living in areas where they don’t have the California variant,” Montefiori said.
“It’s always nice to get this type of result,” he added.
But with both vaccines, there was a significant drop in performance compared to the South African variant.
These lab results weren’t perfect, but they weren’t much of a surprise. In clinical trials, the Novavax vaccine was 89% effective in the UK, but only 49% in South Africa, where B.1.351 dominates.
Likewise, the Johnson & Johnson vaccine, which reduced the risk of moderate to severe disease by 72% when tested in the United States, was only 64% effective in South Africa. And a vaccine developed by AstraZeneca and the University of Oxford did not perform better than a placebo when tested in a South African clinical trial.
The new article was one of many published Wednesday in the New England Journal of Medicine regarding viral variants and vaccines.
A team of South African researchers who tested the blood plasma of patients who had been infected with the South African variant reported that, in addition to protecting against the local variant, their antibodies also 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 range of variants, the researchers suggested.
In another article, Israeli scientists looked at antibody responses in blood samples from six healthcare workers who had been infected and then received a dose of the Pfizer vaccine. They found that after vaccination, their immune systems reactivated against the original virus and the British, Brazilian and South African variants, with antibody responses 114, 203, 81 and 228 times higher, respectively. , than before their injections.
“This highlights the importance of vaccination even in previously infected patients, given the added benefit of an increased antibody response to the variants tested,” the researchers wrote.
The South African variant may raise concerns about vaccine resistance, but so far it has little more than become established in the United States, Montefiori said. According to the CDC, there were 386 confirmed cases involving B.1.351 on Tuesday, up from 16,275 involving the UK variant.
It’s important to keep in mind that these types of tests don’t measure the full degree of protection that a vaccine offers to a real person, said Dr Monica Gandhi, an infectious disease expert at UC San Francisco who did not participate in the new search. .
For example, these tests focus on antibodies, but not on T cells, which are another crucial arm of the immune system’s defenses.
“This is a lab study,” Gandhi said. “It doesn’t tell us in real life if these vaccines won’t be able to produce enough T cells, which is extremely difficult to measure, to bring down the South African virus.”
John Moore, a virologist at Weill Cornell Medical College who was not involved in the new work, agreed.
There is little that can be extrapolated from the immune response observed in blood samples, but a study like this provides useful clues “as to whether or not different variants are or are not likely to be. pose a problem for vaccines, ”Moore said. “He’s a guide.”