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The discovery of several new variants of the coronavirus that could spread more easily, including a mutation that took hold in the Bay Area in December, makes it even more urgent to correct the struggling vaccination rollout in the country – before the evolution of the virus causes another flare or learns. to escape vaccines.
Throughout the year-long pandemic, public health experts have indicated that beating the virus is a marathon, that it would take several months of commitment to social distancing to win. It’s still true. But in many ways, the race has intensified in recent weeks: between a virus that produces new mutations that could make it harder to contain and a vaccination campaign marked by repeated escapes.
“We’re really in a race now,” said Dr. Charles Chiu, the UCSF virologist who identified the L452R variant that exploded in parts of the Bay Area over the past month. “This only increases our urgency to mass vaccinate the population before other variants evolve and emerge.”
A worrying aspect: the more the coronavirus circulates in the community, the more likely it is to mutate and develop into new variants. And there have never been more viruses in California and the United States than today – and many other countries are struggling to contain it as well, creating more risk in an interconnected world.
“By letting the virus run rampant, we allow it to accumulate many mutations. And some of them can be beneficial for the virus, ”said Dr. Catherine Blish, an infectious disease specialist at Stanford. “The best thing we can do right now is get the vaccine as quickly as possible to as many people as possible to reduce the total burden of infection, so that we accumulate fewer mutations.
“We cannot stop the virus from mutating,” she said. “But we can really get the upper hand here.”
The United States, and California in particular, are in dire straits in the pandemic. The country surpassed 400,000 COVID-19 deaths on Tuesday, and in California, cases and daily deaths have been extremely high for weeks.
Meanwhile, the vaccination campaign the country needs to escape the pandemic has been fraught with problems, both state and nationally – most recently with 330,000 doses of Moderna withdrawn from circulation in California. due to concerns about allergic reactions.
One new variation, or more, has the potential to make a bad situation worse. If a more infectious version of the virus takes over, it could re-energize a surge that’s just starting to stabilize. And it could potentially undermine vaccination efforts if vaccines are less effective against it.
The immediate threat to the Bay Area and the rest of the state from new variants is not yet clear. The highly infectious B117 variant which is spreading widely in the UK has been identified in Southern California, but only in a few dozen cases. But the Centers for Disease Control and Prevention warned last week that the variant could become the dominant version of the virus in the United States as early as March and could fuel a further massive increase in cases.
The L452R variant, which was announced in California on Sunday, appears to have a foothold in parts of the state and has been linked to several large outbreaks in Santa Clara County, but scientists are uncertain whether it is more contagious than the virus. type that has circulated in California to this day. While the L452R turns out to be more contagious, it’s unclear how the competition would go between it and the B117 variant.
The B117 variant is not able to escape vaccines, but scientists are not familiar with the L452R variant. Neither appears to cause more serious illness – although a more infectious virus would inevitably lead to more illness and death.
The emergence of the two new variants in California, along with at least two others spreading to other parts of the world, raises new concerns about mutations that may still be occurring or may already be there that have not. just not yet been detected. Experts say the arrival of these variants shows more clearly than ever that the pandemic must be brought under control quickly.
“With 3,000 or 4,000 people dying every day (in the United States), we were already in a race with the virus we knew, and now we’re going to add another element,” said Dr. Robert Wachter, president of the department. of medicine at UCSF. “It’s like you’re in a race and suddenly the person you’re running against is 50% faster.
“Once we had two incredibly effective and safe vaccines, that was really how fast can you get that in people’s arms,” he said. “Not only because of the threats that were obviously pretty clear, but also the emerging threats that will manifest over time.”
The coronavirus, like all other so-called RNA viruses, mutates regularly. But the COVID-19 virus tends to mutate at a slower rate than many other viruses, adopting only one or two mutations per month. Most of these mutations have little or no effect. Some make the virus less likely to survive. Other mutations make it slightly more or less infectious. Or they alter the way the virus interacts with the body’s immune system, making it a more difficult target for natural immunity or a vaccine.
When enough mutations accumulate, a new variant emerges that is genetically separated from its parent and behaves in a significantly different way. The B117 variant has 23 mutations and is much more infectious than its parent. Another variant found in South Africa also appears to spread more easily.
The L452R variant has five mutations. Infectious disease experts fear it is also more contagious, if only because of how quickly it has taken hold in the region and other parts of the state. But they don’t yet know how these mutations affect his behavior.
Another major concern that so many variants have been detected in such a short time frame is that this coronavirus is mutating faster than most scientists thought. This is probably due in part to simple calculations – there are so many viruses circulating in the world right now that even at a slow rate of mutation, the alterations will build up.
Public health experts say that as of yet, there is no evidence that the new variants are not susceptible to vaccines. But lab tests suggest that some variants, including L452R, have a mutation that can make vaccines less effective. Much more research needs to be done, Chiu and others said.
The good news is that the vaccines currently in use can be easily modified to match a new variant, infectious disease experts have said. This is not an ideal situation, however – it would certainly complicate an already chaotic vaccination campaign. And it would take a much more aggressive surveillance effort to identify new variants and determine how well vaccines work against them.
The possibility that a variant will escape vaccines could become more pronounced as more people become immunized, infectious disease experts say. Vaccinating people puts pressure on the virus to mutate for its survival. Random mutations that allow the virus to escape the vaccine will be favored – and more likely to replicate.
“If you have a virus circulating that is now meeting immune control (from a vaccine), you will help, with a much higher probability, evolve variants that will fit and grow better,” said the Dr Melanie Ott, director of the Gladstone Institute of Virology, an independent research group in San Francisco.
It also means that a clumsy immunization schedule that leaves large gaps in protection could make the emergence of a variant that can escape vaccines more likely, she said. Much of the world does not yet have access to vaccines, so even if the United States does tame the virus, it should be vigilant about the virus crossing borders.
Until the herd’s immunity is achieved and the virus stops circulating, variants will remain a problem.
“If we are too slow, we will potentially have variants that could be less sensitive to the vaccine. We will have a situation where the vaccine is partially inactive, ”said Ott. “We need to get as many people vaccinated as quickly as possible, so that we have as little virus as possible in circulation.”
Erin Allday is a writer for the San Francisco Chronicle. Email: [email protected] Twitter: @erinallday
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