5 things to know about the new coronavirus variant that was found in the UK

Coronavirus testing at Quinsigamond Community College in Worcester earlier this month.Erin Clark/Globe Staff

The coronavirus has swept across the world, sickening tens of millions and killing nearly 1.8 million people while governments have struggled to control the spread. Now a new variant of the virus is raising concern, and the latest reports confirm it has arrived in the United States. Here’s a quick rundown, with the help of Globe wire services, of what you need to know.

What’s the latest news?

British officials sounded the alarm about the variance earlier this month. As of Wednesday, the variant had been detected in two US states, California and Colorado.

Expect more cases. The US Centers for Disease Control and Prevention said in a statement Tuesday that additional cases with the new variant will be detected in the United States in the coming days. Other new variants have also been discovered, including one in South Africa that also seems to spread more easily, according to the CDC, which says it is “monitoring the situation closely.”

Why are people concerned?

The major concern about the virus discovered in Britain is that it appears to be more transmissible. Preliminary analyses suggest the new variant of the SARS-CoV-2 virus is 56 percent to 70 percent more transmissible than other circulating strains of the virus. Greater transmissibility raises the specter that many more people will be infected.

Trevor Bedford, who studies the spread of COVID-19 at the Fred Hutchinson Cancer Research Center in Seattle, told The Associated Press he was worried “there will be another spring wave due to the variant. ... It’s a race with the vaccine, but now the virus has just gotten a little bit faster.”

The variant’s apparent increase in transmissibility “could lead to more cases and place greater demand on already strained health care resources,” the CDC said in its statement Tuesday.

Officials have emphasized the need to continue to take steps such as wearing face coverings, socially distancing, avoiding large gatherings, ensuring good ventilation in indoor spaces, and washing hands frequently.

“We need to be even more vigilant in our prevention measures,” Dr. Henry Walke, CDC incident manager for COVID-19 response, said in a media briefing Wednesday. “We firmly believe that our mitigation measures that are in our guidance now will work” to stop the new variant.

Does it cause more severe illness?

One piece of good news: Scientists in Britain have found no evidence that the new variant is more lethal or causes more severe illness. But experts are warning that people shouldn’t take too much comfort in that fact because, if the new variant does transmit to many more people, it will still lead to many more people falling ill and possibly dying.

“I think the intuitive response ... is to breathe a sigh of relief,” said Stephen Kissler, research fellow in the Department of Immunology and Infectious Diseases at Harvard T.H. Chan School of Public Health. However, he said Wednesday in a media briefing, “Having a strain that’s more transmissible is in some ways a greater threat. Because with something that grows exponentially like this, due to the increased burden of infection that you end up getting, it can actually lead to a greater total number of severe illnesses and deaths.”

How did the new variant arise?

Scientists say there’s nothing new about a virus mutating. Viruses constantly mutate naturally as they replicate and circulate in their hosts. As a result of this ongoing process, many thousands of mutations and distinct lineages have already arisen in the SARS-CoV-2 genome since the virus emerged in late 2019, the Washington Post reported.

“Many mutations lead to variants that don’t change how the virus infects people. Sometimes, however, variants emerged that can spread more rapidly,” CDC’s Walke said.

Will the vaccines still work?

Experts and drugmakers have said the efficacy of the vaccines currently being administered won’t likely be affected. Maria Van Kerkhove, the World Health Organization’s technical lead on COVID-19, told the BBC Dec. 20 that current information suggests the new variant doesn’t have any impact on the vaccines being rolled out. Drugmakers have said they don’t believe their vaccines’ efficacy will be affected. Over time, however, as more mutations occur, vaccines may need to be altered, the Post reported.

“What we know from experience with this mutation and other mutations is that it’s unlikely to have a large impact on vaccine-induced immunity, or an existing immunity” from getting the coronavirus, CDC official Greg Armstrong said in the briefing. He said it was the “opinion of experts from around the world.”

Material from Globe wire services was used in this report.