The discovery of a more contagious coronavirus strain in the United States this week has turned the battle against COVID-19 into a high-stakes race between the newly authorized vaccines and a virus that soon may spread even faster.
That’s what scientists are saying after the first US case of the easily transmitted “British variant” of COVID-19 was confirmed in a Colorado National Guardsman with no recent history of travel. They say the new strain may already be spreading undetected elsewhere in the US — a second possible case in Colorado and one in California were being investigated Tuesday — heightening the urgency to ramp up the sluggish national vaccine rollout that’s already behind schedule.
The variant “could be here in Massachusetts, certainly,” said Bill Hanage, an epidemiologist at Harvard’s T.H. Chan School of Public Health, who warned a dearth of genomic tracking may have left the mutant strain invisible in most of the country. “It’s reasonable to assume that it’s here.”
Federal and Massachusetts officials are monitoring the new virus strain closely and are careful to say it does not appear to cause a higher risk of death — it’s just easier to pass from person to person. Drug makers and public health figures think the vaccines will be effective in neutralizing the variant, first detected in Great Britain, though they’re waiting for clear evidence of that.
“The one thing that appears to be true about this mutant is it’s highly, highly contagious,” Massachusetts health and human services secretary Marylou Sudders said Tuesday.
Dr. Henry Walke, incident manager for COVID-19 response at the Centers for Disease Control and Prevention, told a press briefing that “the arrival of this variant in the United States was expected, considering how widespread it is in the United Kingdom and how frequently people travel between the US and the UK.” Walke said the lack of reported travel history of the first man infected “suggests the variant has been transmitted from person to person in the United States.”
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Pandemic fighters see a looming threat in the coming months: Without faster progress in the push to immunize hundreds of millions of Americans, the nation could face new spikes in infections and more onerous lockdowns.
“We need to be in overdrive now,” said Dr. Irwin Redlener, a Columbia University professor and director of the Pandemic Resource and Response Initiative. “We need to move as rapidly as possible to get the whole population vaccinated.”
But about two weeks after its launch, the US vaccination push has been running far behind early projections of 20 million doses administered by the end of the year. Only about 2.6 million Americans, including 75,000 in Massachusetts, have been given the first shots in the two-dose Pfizer and Moderna regimens authorized for emergency use this month.
On Wednesday, the state reported 118 new confirmed coronavirus deaths in Massachusetts, increasing the total deaths during the pandemic past 12,000.
Immunologists say the main danger of the mutant virus strain, called B.1.1.7, is that it has the potential to boost the number of US coronavirus cases substantially. That could further strain health systems across the country and lead to school closings and tougher restrictions on movement such as the lockdown that’s idled much of southern England over the holidays.
British researchers have estimated the new variant is more than 50 percent more transmissible than standard COVID-19.
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“With this [strain] rising and emerging, it makes vaccination all the more important,” Hanage said in an interview. “If it’s more transmissible, we need to deny it the opportunity to transmit and make things so much worse than they are.”
Perhaps the most critical question pondered by scientists is whether the first COVID-19 vaccines — authorized and under development — will be effective against the British strain, which has now been identified in about 20 other countries from Canada to India to the United Arab Emirates.
Viruses are constantly mutating, undergoing small changes as they reproduce and move through populations. Because the coronavirus mutations identified so far appear to be minor and relatively small in number, scientists believe the vaccines will work against the British variant, as well as another mutant coronavirus strain that has cropped up in South Africa. (CDC officials said there’s no evidence that strain is in the US.)
But scientists are awaiting definitive proof from tests that are being conducted in research labs in Boston and elsewhere on whether the vaccines effectively block the variant.
“There’s a high chance these variants are already circulating around the United States,” said Dr. Dan Barouch, director of the Center for Virology and Vaccine Research at Beth Israel Deaconess Medical Center in Boston, whose lab is among those testing whether antibodies found in the blood of convalescent COVID-19 patients and people who’ve gotten vaccines will neutralize the virus variants.
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“I don’t believe there’s need for alarm, but we need to generate the data to determine whether this is a problem,” said Barouch, whose lab has also been working with drug maker Johnson & Johnson on a new one-shot vaccine.
Vaccine makers Moderna and Pfizer, which is working with German partner BioNTech, both released statements saying the messenger RNA technology used in both of their vaccines give them flexibility to combat mutant strains. Both companies said their scientists are working to generate data on how well vaccinated Britons are protected against the variant.
The statement from Cambridge-based Moderna said that the company planned to test its vaccine on the mutant strains of COVID-19, but the flexibility of Moderna’s approach “provide confidence that our vaccine will also be effective at inducing neutralizing antibodies against them.”
Similar testing being done in labs from Maryland to Texas are being closely watched by infectious disease specialists in the US and abroad.
“Typically, you need multiple mutations in order to evade the immune response to vaccines,” said Dr. Daniel Kuritzkes, chief of the division of infectious diseases at Brigham and Women’s Hospital in Boston. “The similarities among these strains is much more than the similarities between flu strains. There’s good reason to believe the vaccines will be effective against all these circulating new strains.”
While the readily spread British strain has prompted dozens of countries to restrict travelers from the United Kingdom or show proof of a negative COVID-19 test before they can enter, it’s not even clear the variant originated in the UK, said Hanage. The variant may simply have been detected first in Britain because the UK is a world leader in genomic epidemiology, he said, sequencing more than 10 times the number of coronavirus genomes as the United States.
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“It’s not being done at the same scale here,” he said. “In the US, we don’t look at the genomes. It’s ridiculous.”
Robert Weisman can be reached at robert.weisman@globe.com.