Easier-to-Spread Covid Variant in U.S. Amps Up Vaccine Urgency

An easier-to-spread variant of Covid-19 detected in the U.S. for the first time last week could intensify the virus’s surge, if it hasn’t already, boosting the urgency for a speedier, more effective vaccine push.

Only three states — Colorado, California and Florida — haveidentified cases of the mutated strain that’s been raging in the U.K. for months. But U.S. health officials say they don’t yet know how far the variant may already have traveled in the U.S., or what it could mean for the future.

“I suspect it’s more widespread than we know,” said Michelle Barron, senior medical director of infection prevention and control atUCHealth, a health-care system with a dozen hospitals and hundreds of clinics in Colorado. “It’s a function of ‘if you look for it, you will find it.’”

The discovery of the mutant strain in the U.S. comes as the drive to vaccinate most Americans has been hampered by ineffective coordination and a lack of federal support for states and health-care systems. While more than 4.28 million Americans had been vaccinated as of Saturday evening, according to Bloomberg’svaccine tracker, that’s far fewer than the 20 million doses U.S. health officials predicted for the end of 2020.

Meanwhile, the number of infections is surging, with almost 231,000 new cases reported in the U.S. on Thursday before the holiday weekend, when reporting can be sporadic. Four states — including New York and California — have surpassed 1 million infections overall, and more than 350,000 Americans have died.

“It is a race, and this variant has made the whole challenge more formidable,” said Eric Topol, director of the Scripps Research Translational Institute in La Jolla, California. “Whatever we saw in 2020 in terms of a challenging virus, it’s going to be taken to a new level.”

Distributing vaccineshas been a challenge for a U.S. health system strained by a concurrent surge in infections. State and local governments are struggling with complex logistics to keep the shots cold, deciding who should get early access, and persuading vaccine skeptics.

To boost the amount of vaccine available, the U.S. government is considering cutting by half the dose of theModerna Inc. shot given to those 18 to 55, said Moncef Slaoui, Operation Warp Speed’s chief scientific officer, on CBS’s “Face the Nation.” He said there is evidence showing the half-dose provides the same level of protection for that age group.

Slaoui’s comments came in response to a question about the U.K’s decision to get as many people as possible their first dose of a vaccine fromPfizer Inc. andBioNTech SE, while possibly delaying a second dose. He said such a shift would be a mistake for the U.S. since it wasn’t supported by trial data.

CDC Studies

Meanwhile, the U.S. Centers for Disease Control and Prevention is currently attempting to model what effect the variant could have on accelerating spread, according to Kristen Nordlund, an agency spokeswoman. At this time, though, “we do not have results,” Nordlund said in an email.

Prior to November, only a select number of U.S. cases had been sequenced, a laboratory procedure that can determine the genetic makeup of the pathogen as it travels through the population. Since then, however, the CDC has launched a national program to detect novel strains, said Greg Armstrong, director of the CDC’s advanced molecular detection program.

The CDC is now scaling up to sequence 750 samples on its own each week, according to Armstrong, and the agency is partnering with labs around the country to map the genetic material of about 1,750 virus samples weekly.

The agency is also exploring whether the mutations could make existing treatments less effective, according to Henry Walke, the CDC’s Covid-19 incident manager. Still, there’s no reason that measures like wearing a mask and social distancing would be less effective in preventing transmission of the new strain, he said during a call with reporters last week.

Mutating Viruses

Viruses have the opportunity to change through mutations that arise naturally as they replicate and circulate in their hosts. Some, like influenza, evolve quickly with thousands of mutations and distinct lineages, while others are more stable.

The new variant, known scientifically as B.1.1.7, contains a huge number of mutations, which is unusual, said Andy Pekosz, director of the Center for Emerging Viruses and Infectious Diseases atJohns Hopkins University. A particular concern is the change in the spike protein, which binds to human cells, allowing the virus to gain entry.

Scientists suspect these mutations are making it easier for the spike protein to attach. The new strain is thought to be 57% to 70% more transmissible than other strains of the virus.

U.K. Prevalence

In the U.K., the new variant was responsible for 62% of Covid-19 infections in London in the week ending Dec. 9, up from 28% in early November, according to Paul Hunter, a professor of medicine at theUniversity of East Anglia’s Norwich School of Medicine. Cases have also been identified in more than a dozen other countries, including Australia, Canada, Germany, Italy, Japan, Lebanon, the Netherlands, Singapore and South Korea.

In Colorado, state scientists are attempting to do full genetic sequencing on any samples that show signs of the U.K. variant, according to state scientific director Emily Travanty. Samples are flagged when only two of the three genes targeted by the gold-standard PCR tests used by the state are found, indicating a mutation has occurred in the third — the critical spike protein.

The missing gene is present, according to Travanty, but rendered undetectable by the test because of the mutation, making it a signature of the variant, she said. When laboratories find that red flag, it indicates more investigation is needed.

Much Unknown

“There is a lot we don’t know about this variant,” Colorado Governor Jared Polis said last week after the first U.S. case was discovered in his state. “But if it does transmit more quickly, more people will get it and more people will be hospitalized.”

Still, there are some positive findings related to the variant. It is apparently not any deadlier, though if more people are infected, there would be more deaths. And it is not thought to be able to overcome the two vaccines already being distributed in the U.S., thePfizer Inc.-BioNTech SE shot, and theModerna Inc. shot.

“There is a good news here,” Topol said. “It will not affect the vaccine’s efficacy. That’s why there is this race. If we get ahead of this and get everyone vaccinated, if we do that quickly, we will have this virus under control.”

Speed of Transmission

Meanwhile, in the U.K., the added speed of transmission thought to be related to the new strain has been noticeable. The number of new cases has risen dramatically in recent weeks, even as the country instituted stronger and stronger lockdowns, said Michael Osterholm, director of the Center for Infectious Disease Research and Policy at theUniversity of Minnesota.

In the U.S., mask-wearing and social distancing have often been more a political issue than a public health one, with at least one adviser to President Donald Trump suggesting that herd immunity, which occurs when enough people become immune to a disease to make its spread unlikely, can be reached by simply letting the disease run free.

While that theory could be more easily tested by letting the new variant run wild, the cost would be considerable more cases and deaths among Americans. The best idea is to get the country to herd immunity based on higher rates of vaccination, not transmission, Osterholm said.

”Getting there with infection or vaccination, with protection or disease — we will get there,” Ossterholm said. “Our job is to minimize disease-related protection.”

Drift Over Time

The virus’s makeup will drift over time as is the case with all viruses, scientists suggest, and the changes could eventually warrant a new vaccine. But that could take years, they said.

Still, the risk exists that the virus could build off the new variant, creating more devastating mutations that could trigger more severe disease or render vaccines and therapeutics ineffective.

“Every time it accumulates new changes, it opens up the landscape for where the virus can evolve into,” according to Pekosz at Johns Hopkins. “This virus is mutating, but is it evolving? We don’t know yet. That’s why we have to monitor the changes.”

Take influenza, for example. When it interacts with people who have immune protection, it will mutate to get around that immunity, Pekosz said. Measles, on the other hand, tends to die off.

“The coronavirus hasn’t seen enough people with immunity to it to let us predict what it’s going to do,” he said.

— With assistance by Angelica LaVito

Source: Read Full Article