In recent days, the world has watched with curiosity and growing alarm as British scientists describe a newly identified variant of the coronavirus that appears to be both more contagious than the more known, as well as being genetically different. Initial studies of the new variant prompted Prime Minister Boris Johnson to tighten Christmas restrictions and to urge authorities in the Netherlands, Germany and other European countries to ban travel from the UK.
At present, the new variant is the focus of intensive debate and analysis. This is part of what scientists have discovered so far.
Is the British variant some sort of new super virus?
No. This is just one of the many variants that have emerged as the SARS-CoV-2 coronavirus has spread around the world. Mutations occur when the virus replicates, and this variant – known as B.1.1.7 – already has its own signature sequence.
What’s unusual about it?
The variant came to the attention of researchers in December, when it was increasingly common in samples from regions of southern England. It turned out that they had been decreasing in patients since September.
When the researchers took a close look at the genome, they were shocked by the relatively large number of mutations it had developed – 23 in all. Most mutations that arise in the coronavirus are harmful to the virus or have no effect. However, it appeared that several of the mutations in B.1.1.7 could affect the way the virus spreads.
Is it more contagious than other viruses?
It seems. In preliminary studies, British researchers found that the virus is spreading rapidly in parts of southern England and is displacing a host of other variants that have been circulating for months.
However, the fact that one strain of the virus is becoming more common is no evidence that it is spreading faster than others. It can spread by chance. For example, a variant could emerge within a densely populated city where it can be easily transferred and thus make more copies of itself.
However, the epidemiological evidence gathered in England so far seems to indicate that this variant is very spreading. Where it occurs more often, the total number of coronavirus cases is skyrocketing. Neil Ferguson, a public health researcher at Imperial College London, considers the high transmission speed of this variant to be between 50 and 70 percent, compared to other variants in the UK.
Some scientists have considered the possibility that the increase in transmission is, at least in part, a result of how it infects children. Children are generally less likely to contract or transmit the virus than adolescents or adults. However, the new strain may make children “as susceptible as adults,” said Wendy Barclay, a government advisor and virologist at Imperial College London.
Does it cause a more serious illness?
There is no hard evidence to confirm this so far. However, there are reasons to take the opportunity seriously. In South Africa, another strain of the coronavirus has developed a particular mutation that is also found in B.1.1.7. This variant is spreading at full speed through the coastal areas of South Africa. In addition, in preliminary studies, doctors found that people infected with this variant have an increased viral load – a higher concentration of the virus in their upper respiratory tract. In many viral diseases, this is associated with more serious symptoms.
Where does this unusual variety come from?
There is intense debate around that question. One possibility is that the variant has evolved its set of new mutations within a special set of hosts.
In a typical infection, people contract the coronavirus and become contagious for several days before showing symptoms. Later, the virus becomes less abundant in the body as the immune system forces a defense. Unless patients have a severe COVID-19 case, they usually get rid of the virus completely within a few weeks.
Sometimes, however, the virus infects people with weak immune systems. The virus can develop in their bodies for months. Case studies in these immunocompromised people have shown that the virus can accumulate a wide range of mutations when it multiplies in their bodies over a long period of time.
Some researchers have found that natural selection may favor mutant viruses that over time evade the immune system. They have also suggested that the evolution of the variant may have received an extra boost from the drug given to those patients. Some mutants can be tolerant to drugs such as monoclonal antibodies.
Other scientists have pointed out that the virus may have evolved new mutations by spreading through a particular animal population, such as mink, before re-entering the human population. These “animal reservoirs” have become a focus of great interest as more infections in animals have been discovered.
Is the variant already in circulation in the United States?
As far as known not yet. However, this is not to say that it did not reach the United States. British scientists have developed a much better system to check coronaviruses for new mutations. Someone traveling from the UK may have brought it. Now that the world knows to look for the variant, it may appear in more countries.
Will the variant render new vaccines ineffective?
No. Most experts doubt whether it has a significant effect on vaccines, although it cannot yet be ruled out that there is an effect.
The Food and Drug Administration has approved two vaccines, one from Moderna and the other from Pfizer and BioNTech. Both vaccines create immunity to the coronavirus by teaching our immune system to make antibodies to a protein, called a spike, found on the surface of the virus. The spike protein grabs on cells and opens a passage in them. Antibodies produced in response to vaccines stick to the tip of the spike. The result: viruses cannot penetrate.
It could be that a mutation in a coronavirus changes the shape of its spike proteins, making it difficult for antibodies to get to grips with. In addition, eight of the B.1.1.7 mutations are found in the spike gene. However, our immune system can produce a whole host of antibodies to a single viral protein, making it less likely that viruses can easily escape their attack. At the moment, experts don’t believe the variant can evade vaccines. To confirm this, researchers at the Walter Reed Army Research Institute are analyzing changes in the structure of the spike protein.