A new variant of the coronavirus is spreading rapidly in England and raising international alarms. This new variant now accounts for more than 60% of the cases in London. And scientists say the variant is likely more contagious than previous versions of the virus.
Health officials have closed international travel to the United Kingdom. The British government has locked down much of the country. And scientists all over the world are rushing to figure out how the virus mutated and how big a threat the new variant poses.
Here's what we know so far:
Throughout this pandemic, SARS-CoV-2 — the virus that causes COVID-19 — has been mutating. It has accumulated about one or two mutations each month. That's not surprising. Viruses always mutate.
But this new variant in the U.K., called B.1.1.7, has acquired mutations much quicker than scientists expect. The variant has 17 different mutations in its genetic code. And eight of those mutations occur in a critical part of the virus, called the spike protein, which reaches out and binds to human cells during the initial stages of infection.
Scientists have already studied several of the mutations occurring in B.1.1.7, and they are cause for concern. One mutation, called N510Y, makes the virus bind more tightly to human cells. This mutation has also appeared, independently, in a rapidly spreading variant in South Africa.
Another mutation, called D614G, makes the virus more transmissible. B.1.1.7 also contains a small deletion in the virus's genetic code, called 69-70del, and that deletion helps the new variant evade the body's immune system in some people.
These mutations, combined with the fact that B.1.1.7 acquired many changes simultaneously, suggest this new variant didn't arise by chance, but rather the mutations are giving it an advantage. They are helping it adapt to humans.
When scientists first detected B.1.1.7 in late September, it rapidly took over parts of England, pushing out other forms of virus. By early December, the new variant had pushed out other forms of the virus in London and become the dominant one.
This rapid rise suggests B.1.1.7 is more transmissible than other forms of the virus. "There's no hard evidence, but it seems most likely," says biochemist Jeremy Luban at the University of Massachusetts Medical School. "So if a person sneezes on a bus, the new variant is more likely to infect other people than the previous form of the virus."
To figure out transmissibility for certain, scientists have to bring B.1.1.7 into the lab and see if it's better at infecting cells and spreading between animals.
SARS-CoV-2 is already spreading quickly around the world. So a small increase might not make a big difference. It depends on how much better B.1.1.7 spreads.
In the end, how quickly the virus spreads depends on many factors, including people's behavior in a community. That is, whether they wear masks, physically distance and avoid big gatherings. Those factors could be more important than whether B.1.1.7 arrives in a community, says virus expert Pei-Yong Shi at the University of Texas Medical Branch. "With all these human interventions, it's hard to predict the course of the pandemic."
Scientists don't know for sure because this variant has just emerged, but so far, people who catch B.1.1.7 don't seem to be getting sicker.
"There is absolutely no evidence that this [variant of the] virus is more deadly," Luban says. "There's nothing at all to suggest that, and I don't think anyone that I know is worried about that possibility."
Again, scientists don't know for sure if the vaccines will work as well with B.1.1.7. as they do with previous forms of the virus. They need to test out the new variant in laboratory experiments. But many scientists are optimistic.
Why? When we get a vaccine, our immune systems make many antibodies against a big chunk of the virus, not just one small section that could change when the virus mutates. So even if the variant contains 17 mutations, some antibodies targeting the vaccine will likely still bind and neutralize the virus.
"So if you're in line for the COVID-19 vaccine, stay in line. Don't give up your spot. Take it," says microbiologist Andrew Pekosz of Johns Hopkins University. "You know, everything is still looking good from the vaccine standpoint."
Researchers have already detected it in Denmark, the Netherlands and Australia.
The U.K. has been vigilant about looking for new variants and following them. Other countries, including the U.S., haven't been tracking variants as closely. So new variants, such as B.1.1.7, have likely gone undetected.