Early studies show that the coronavirus variant that is spreading widely across California is somewhat resistant to antibodies that fight infection, but vaccines must still offer sufficient protection, infectious disease experts say.
Antibodies generated by vaccines, or by previous coronavirus infection, were two to four times stronger against previous versions of the virus compared to the new variant, UCSF scientists found in laboratory studies. They released preliminary results this week.
The finding is disappointing, but it is not a cause for alarm, said the scientists involved in the study, as well as outside observers. Vaccines are extremely powerful and, even with a drop in antibody strength, they are likely to be just as effective against the variant as against the original version of the virus that they were designed to fight.
If efficacy is reduced, vaccines should still prevent almost all cases of serious illness and death, even for the new variant.
“In my opinion, it won’t make a difference in terms of the vaccine’s effectiveness,” said Raul Andino, a virologist at UCSF who led the research on variant antibodies. “I would say that there is nothing to fear now.”
The California variant is now dominant in much of the state; there are technically two variants, known as B.1.429 and B.1.427, but they are almost identical and carry the same key mutations. Scientists are generally studying them as a unique variant.
Two teams of UCSF scientists released 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 illnesses and be resistant to antibodies.
All the results suggest that this variant is worrying and should be monitored closely. The fact that it is so widespread should remind people to be vigilant about wearing masks and to maintain social distance, even when the winter wave subsides and the state reopens, experts warn.
But antibody research in particular is important to put into context, say the scientists. The research itself is critical: if the variants seem capable of escaping vaccines, public health officials want to know about it immediately. Vaccine manufacturers also need to know whether to update their formulas to better match the new variants.
The California variant – along with one from South Africa – could make vaccines marginally less effective in subtle but important ways. As with so many aspects of this pandemic, scientists will not have all of these answers until they have done more research.
Studies in South Africa have shown that vaccines work a little less well against a different variant. The Johnson & Johnson vaccine, for example – which the Food and Drug Administration is considering for emergency clearance – is about 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 found it to be less effective; the new version is still under review.
Similar studies have not yet been done for the California variant. For now, the only sign that there may be problems is antibody resistance in the laboratory, but that does not mean that vaccines will not work in real life.
Antibodies are the immune system’s most powerful response to disease-causing pathogens. They are specialized proteins released by the immune system to attack and kill invaders.
When someone is infected with a virus or another pathogen, the immune system learns from that experience, and if it encounters the same virus again, it will quickly assemble an army of antibodies. Vaccines also stimulate the immune system to release antibodies. Vaccines used in the United States elicit huge antibody responses that are about 95% effective in killing the coronavirus.
To understand the effectiveness of the antibody against the new variant, the UCSF scientists did a common experiment called a neutralization assay. They collected antibodies from people who had been infected 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 various dilutions of antibodies for half an hour. Then the antibodies-soaked viruses were mixed with cells in Petri dishes to test whether the viruses were still alive and infectious. Scientists focused on how much antibodies could be diluted and still be able to kill or neutralize the virus.
The UCSF team found that antibodies generated by vaccines could be diluted twice more against the original virus than against the California variant. Antibodies from previously infected people can be diluted four times more.
In other words, the antibodies were stronger against previous versions of the virus compared to the new variant. Similar studies in South Africa have found that antibodies are six to 10 times stronger against the original form of the virus compared to the variant there.
The California variant is likely to cause concern, “but certainly not like South Africa,” said Dr. Jay Levy, an infectious disease specialist at UCSF, who said he found the results released this week reassuring. “Vaccines will work, unless they mutate to make things worse. You are still neutralizing the virus. “
There are several caveats to these initial results, the most important of which are laboratory experiments that analyze the interactions between the virus and antibodies in a highly controlled environment. In real life, the body creates a complex immune response to the virus. This can be further helped or hindered by environmental factors that cannot be replicated in a laboratory.
The vaccine’s effectiveness is also nuanced. Vaccines in use in the United States are almost 100% effective in preventing hospitalization and death from COVID-19, but it is unclear how they protect against asymptomatic diseases. Vaccinated people can still carry the virus. It is also unknown how long the vaccine will last.
The main lesson remains: everyone should be vaccinated when their turn comes, said Bali Pulendran, professor of microbiology and immunology at Stanford.
“If you asked me, ‘would you get the vaccine in the hope that it could offer 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