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Early studies show that the coronavirus variant that spreads widely across California is somewhat resistant to infection-fighting antibodies, but vaccines should still offer sufficient protection, infectious disease experts say.
Antibodies generated by vaccines, or by a previous coronavirus infection, were two to four times more potent against earlier versions of the virus compared to the new variant, UCSF scientists found in laboratory studies. They released the preliminary results this week.
The discovery is disappointing, but not alarming, scientists involved in the study as well as outside observers said. The vaccines are extremely potent, and even with a decrease in the strength of the antibodies, they are likely to be about as effective against the variant as against the original version of the virus they were designed to fight.
If there is a reduction in effectiveness, the vaccines should still prevent almost all cases of serious illness and death, even of the new variant.
“In my opinion, it won’t make any difference in terms of how well the vaccine works,” said Raul Andino, a UCSF virologist who led the research on antibody variants. “I would say there is nothing to worry about at the moment.”
The California variant is now dominant in much of the state; there are technically two variants, called B.1.429 and B.1.427, but they are almost identical and carry the same key mutations. Scientists generally study them as a singular variant.
Two teams of scientists from UCSF published the results of the study this week showing for the first time that the variant appears to be more infectious than previous versions of the coronavirus, and that it can also cause more serious illness and be resistant to antibodies.
All the results suggest that this variant is worrying and should be closely monitored. The fact that it’s so prevalent should remind people to remain vigilant about wearing masks and maintaining social distancing, even as the winter wave wears off and the state reopens, experts warn.
But antibody research in particular is important to put in context, scientists say. The research itself is essential: If the variants appear to be able to escape vaccines, public health officials want to find out right away. Vaccine manufacturers also need to know if they need to update their formulations to better match the new variants.
The California variant – along with that of South Africa – could make the vaccines slightly less effective in subtle but important ways. As with many aspects of this pandemic, scientists won’t have all of these answers until they do more research.
Studies in South Africa have shown that vaccines work a little less well against a different variant there. The Johnson & Johnson vaccine, for example – which the Food and Drug Administration is considering for emergency clearance – is around 64% effective in South Africa and 72% effective in the United States. Moderna updated its vaccine to better match the South African variant after studies showed it to be less effective; the new version is still under review.
Similar studies have not yet been performed for the California variant. Right now, the only sign that there may be problems is resistance to antibodies in the lab, but that doesn’t mean vaccines won’t work in real life.
Antibodies are the most powerful response of the immune system to pathogenic pathogens. These are specialized proteins released by the immune system to target and kill invaders.
When a person is infected with a virus or other pathogen, the immune system learns from this experience and if it encounters the same virus again, it will quickly assemble an army of antibodies. Likewise, vaccines trigger the immune system to release antibodies. The vaccines used in the United States trigger huge antibody responses that are about 95% effective in killing the coronavirus.
To understand the effectiveness of antibodies against the new variant, scientists at UCSF performed a common experiment called a neutralization test. They collected antibodies from infected people and others who had been vaccinated, and diluted these antibodies to varying degrees.
They let samples of the California variant and a non-variant virus soak in the different dilutions of antibodies for half an hour. Then, the antibody-soaked viruses were mixed with cells in petri dishes to test whether the viruses were still alive and infectious. Scientists have focused on how much antibodies can be diluted and successfully kill or neutralize the virus.
The UCSF team found that the antibodies generated by the vaccines could be diluted twice as much against the original virus as against the California variant. The antibodies of previously infected people could be diluted four times more.
In other words, the antibodies were stronger against the earlier versions of the virus compared to the new variant. Similar studies conducted in South Africa found that the antibodies were six to 10 times more potent against the original form of the virus than the variant there.
The California variant should be of concern, “but certainly not like South Africa,” said Dr Jay Levy, an infectious disease expert at UCSF who said he found the results released this week reassuring. “Vaccines will work unless they mutate to get worse. You are still neutralizing the virus. “
There are several caveats to these early results, the most important of which is that they are laboratory experiments that analyze interactions between the virus and antibodies in a highly controlled setting. In real life, the body mounts a complex immune response to the virus. This can be further helped or hindered by environmental factors that cannot be replicated in a lab.
The effectiveness of the vaccine is also nuanced. The vaccines used in the United States are almost 100% effective in preventing hospitalization and death from COVID-19, but it is not known to what extent they protect against asymptomatic illnesses. People who have been vaccinated can still carry the virus. It is not yet clear how long vaccine protection lasts.
The key to remember remains: everyone should take a turn, said Bali Pulendran, professor of microbiology and immunology at Stanford.
“If you asked me, ‘would you take the vaccine in the hopes that it offers some protection against the variants? “He said.” My answer would be a resounding yes. “
Erin Allday is a writer for the San Francisco Chronicle. Email: [email protected] Twitter: @erinallday
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