As the California variant of coronavirus continues to spread in the Golden State and beyond, new research suggests that several vaccines should continue to provide effective defense against it.
The results, published Wednesday in the New England Journal of Medicine, offer Californians a good reason to roll up their sleeves as the vaccination campaign gains traction across the state.
“We don’t expect this variant to be a problem for the vaccines – so that’s really good news,” said lead investigator 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. Scientists say they most likely showed up in the state in May and then became the dominant nuisance amid the deadly vacation flood.
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They made up 56% of the samples from California that 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 the District of Columbia and have spread to Australia, Singapore, Israel, and Denmark.
The California tribe is just one of several so-called varieties of concerns being pursued by the CDC. Others are B.1.1.7 from Great Britain, the P.1 variant from Brazil and the B.1.351 variant 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 are trying to eradicate these variants by vaccinating the population as soon as possible. Not only will this hinder their spread, but it will also rob them of the opportunity to receive new mutations that could make them even more dangerous.
Since these coronavirus variants have emerged well beyond their places of origin, they have raised concerns about whether the current crop of vaccines will be effective in protecting against them. That’s because the variants have acquired genetic mutations that affect the spike protein that the virus uses to enter and enter human cells – and which the vaccines target.
The fear is that the mutations could alter the spike protein so much that an immune system trained to recognize an earlier version of the virus may fail to recognize a variant, leaving a vaccinated person with no biological defense.
A team of researchers therefore decided to test two vaccines.
They tested blood samples from people who had received the COVID-19 vaccine developed by Moderna or a vaccine candidate from Novavax that is not yet approved in the United States. Then they introduced technical versions of viral variants into those blood samples and waited to see what kind of immune system response they elicited.
The dominant strain in the US is called D614G and it was neutralized by blood from people who had received one of the vaccines.
The California variant B.1.429 they tested was slightly less susceptible to both the Moderna and Novavax vaccines, but both shots still produced effective protection, according to the researchers. That’s because the body makes far higher levels of antibodies than are actually needed to neutralize the virus, Montefiori said.
And while the Pfizer BioNTech vaccine hasn’t been studied in this article, it would likely work about as well as the Moderna vaccine because they both use similar technology, he said.
“People in Los Angeles can feel very comfortable getting the current vaccines – that these vaccines will protect them as much as people who live in areas where they don’t have the California variant,” said Montefiori.
“It’s always nice to get such a result,” he added.
However, both vaccines showed a significant decrease in performance compared to the South African variant.
These laboratory results weren’t ideal, but they weren’t exactly surprising. In clinical trials, the Novavax vaccine was 89% effective in the UK, but only 49% effective in South Africa, where B.1.351 dominates.
Similarly, the Johnson & Johnson vaccine, which reduced the risk of moderate to severe illness when tested in the US by 72%, was only 57% effective in South Africa. A vaccine developed by AstraZeneca and Oxford University did no better than a placebo when tested in a clinical trial in South Africa.
The new paper was one of several published Wednesday in the New England Journal of Medicine on viral variants and vaccines.
A team of South African researchers who tested blood plasma from patients infected with the South African variant reported that their antibodies still offer significant protection against the “original” version of the coronavirus as well as the Brazilian strain.
The result: vaccines that target the B.1.351 version of the spike protein may be effective against a number of variants, the researchers suggested.
In another article, scientists in Israel looked at antibody responses in blood samples from six health care workers who were infected and later received a dose of the Pfizer vaccine. They found that after being vaccinated against the original virus and the British, Brazilian and South African variants, their immune systems spun, with antibody responses 114, 203, 81 and 228 times higher than immediately 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 fuel concerns about vaccine resistance, but so far it has done little more than gain a foothold in the US, Montefiori said. There were 386 confirmed cases of B.1,351 on Tuesday, compared with 16,275 cases with the UK variant, according to the CDC.
It’s important to keep in mind that these types of tests don’t measure the full protection a vaccine gives in an actual person, said Dr. Monica Gandhi, an infectious disease expert at UC San Francisco who was not involved in the new research.
These tests look at antibodies, for example, but not T cells, which are another critical arm of the immune system’s defenses.
“This is a laboratory study,” said Gandhi. “This doesn’t tell us in real life if these vaccines won’t be able to produce enough T cells, which is very difficult to measure to fight the South Africa 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 observed in blood samples, but a study like this one provides useful evidence “whether or not different variants are a problem for vaccines,” Moore said. “It’s a guide.”