The discovery of several new variants of the coronavirus that can spread more easily, including a mutation that settled in the bay area in December, makes it even more urgent to correct the country’s problematic vaccination launch – before the evolving virus causes another outbreak. or learn to avoid vaccines.
Throughout the yearlong pandemic, public health experts advised that winning the virus was a marathon, that it would take many months of commitment to social distance measures to win. This is still true. But in many ways, the race has intensified in recent weeks: between a virus that is generating new mutations that may make it more difficult to contain and an immunization campaign marked by repeated mistakes.
“We are really in a race right now,” said Dr. Charles Chiu, the UCSF virologist who identified the L452R variant that exploded in parts of the Bay Area last month. “This only increases our urgency to mass vaccinate the population before other variants evolve and emerge.”
A worrying aspect: the more the coronavirus is circulating 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 now – and many other countries are also struggling to contain them, creating more risks in an interconnected world.
“By allowing the virus to spread wildly, we are allowing it to accumulate many mutations. And some of them can be beneficial for the virus, ”said Dr. Catherine Blish, a specialist in infectious diseases at Stanford. “The best thing we can do now is to deliver the vaccine as quickly as possible to as many people as possible to decrease the total burden of infection, so we are accumulating less mutations.
“We cannot prevent the virus from mutating,” she said. “But we can really take advantage here.”
The USA, and California specifically, are in a precarious situation in the pandemic. The country surpassed 400,000 total COVID-19 deaths on Tuesday, and in California, daily cases and deaths have been overwhelmingly high for weeks.
Meanwhile, the immunization campaign the country needs to escape the pandemic is fraught with problems, both at the state and national levels – most recently, with 330,000 doses of Moderna withdrawn from circulation in California due to concerns about allergic reactions.
A new variant, or more than one, has the potential to make a bad situation worse. If a more infectious version of the virus takes over, it could reinvigorate an outbreak that is beginning to stabilize. And it can hamper immunization efforts if vaccines are less effective against it.
The immediate threat to the Bay Area and the rest of the state from new variants remains unclear. The highly infectious variant B117 that 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 that it could fuel a further massive increase in cases.
The L452R variant, whose presence in California was announced on Sunday, appears to have a foothold in parts of the state and has been linked to several major outbreaks in Santa Clara County, but scientists are not sure if it is more infectious than the type virus that has circulated in California so far. If the L452R is more infectious, it is not clear how the competition between it and the B117 variant would be.
The B117 variant is not able to escape vaccines, but scientists do not know about the L452R variant. Neither seems to cause more serious illness – although a more infectious virus inevitably causes more illness and death.
The emergence of the two new variants in California, along with at least two more spreading in other parts of the world, raises new concerns about which mutations may still arise or may already be here and have simply not yet been detected. Experts say the arrival of these variants makes it clearer than ever that the pandemic must be stopped quickly.
“With 3,000 or 4,000 people dying each day (in the United States), we were already in a race with the virus we knew and now we are 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 competing against is 50% faster.
“Since we had two incredibly effective and safe vaccines, it really was just how fast you can put this in people’s arms,” he said. “Not only because of the threats that were obviously quite clear, but also because of the emerging threats that will emerge over time.”
The coronavirus, like all others 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 a little more or less infectious. Or they change the way the virus interacts with the body’s immune system, making it a more challenging target for natural immunity or a vaccine.
When enough mutations accumulate, a new variant appears that is genetically separated from its mother and behaves in a remarkably different way. The B117 variant has 23 mutations and is much more infectious than its mother. Another variant found in South Africa also seems to spread more easily.
The L452R variant has five mutations. Infectious disease experts fear it may also be more infectious, just because of the speed with which it has spread throughout the region and other parts of the state. But they still don’t know how these mutations affect their behavior.
The fact that so many variants have been detected in such a short time raises another overarching concern: this coronavirus is transforming faster than most scientists thought. This is probably due in part to simple math – there are so many viruses circulating around the world now that, even at a slow mutation rate, the changes will accumulate.
Public health experts say that, for now, there is no evidence that the new variants are not susceptible to vaccines. But laboratory tests suggest that some variants, including L452R, have a mutation that could make vaccines less effective. Much more research needs to be done, Chiu and others said.
The good news is that the vaccines used can now be easily modified to match a new variant, infectious disease experts said. However, this is not an ideal situation – it would certainly complicate an already chaotic vaccination campaign. And it would require 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 may become more evident as more people become immunized, infectious disease experts say. Vaccination of people puts pressure on the virus to mutate and survive. Random mutations that allow the virus to escape the vaccine will be favored – and are more likely to replicate.
“If you have a circulating virus that now finds immune control (from a vaccine), it is much more likely to help develop variants that will be adapted and grow better,” said Dr. Melanie Ott, director of the Gladstone Institute of Virology, a group independent research in San Francisco.
It also means that an awkward vaccination program that leaves big gaps in protection could make it more likely that a variant will escape vaccines, she said. Much of the world has not yet had access to vaccines, so even if the United States domesticated the virus, they would still need to be vigilant about the virus’s arrival across borders.
Until collective immunity is achieved and the virus stops circulating, variants will remain a problem.
“If we are very slow, we will potentially have variants that may be less susceptible to the vaccine. We will have a situation where the vaccine is partially inactive, ”said Ott. “We need to vaccinate as many people as quickly as possible, to have as little virus as possible circulating.”
Erin Allday is a writer for the San Francisco Chronicle. Email: [email protected] Twitter: @erinallday