A more contagious form of the coronavirus has begun to spread in the United States.
In Britain, where it was first identified, the new variant became the predominant form of the coronavirus in just three months, accelerating the country’s boom and filling its hospitals. It could do the same in the United States, exacerbating a relentless increase in deaths and overwhelming the already strained health care system, experts warned.
A variant that spreads more easily also means that people have to follow precautionary measures such as social distance, mask wear, hand hygiene and improved ventilation in a religious way – unwelcome news for many Americans who are already coming out against restrictions.
“The bottom line is that everything we do to reduce transmission will reduce the spread of any variant, including this one,” said Angela Rasmussen, a virologist at Georgetown University. But “it may mean that the more targeted measures that are not like a complete exclusion will not be as effective.”
What does it mean that this variant is more transferable? What makes this variant more contagious than previous iterations of the virus? And why should we worry about a variant that spreads more easily, but does not seem to make someone sicker?
We asked experts to consider researching this new version of the coronavirus.
The new variant seems to spread more easily between people.
Many variants of the coronavirus have emerged since the pandemic began. So far, all evidence suggests that the new mutant, named B.1.1.7, is more transmissible than previous forms. It first surfaced in Britain in September, but is already responsible for more than 60 per cent of new business in London and surrounding areas.
The new variant appears to infect more people than earlier versions of the coronavirus, even if the environments are the same. It is not clear what the advantage of this variant is, although there are indications that it can infect cells more efficiently.
It is also difficult to say exactly how much more transmissible the new variant may be, because scientists have not yet done the kind of laboratory experiments required. Most conclusions have been drawn from epidemiological observations, and ‘there are as many biases as possible in all the available data’, warns Muge Cevik, an infectious disease expert at the University of St. Petersburg Andrews in Scotland and a scientific adviser to the British Government. .
Scientists initially estimated that the new variant was 70 percent more transferable, but a recent model study linked 56 percent. Once researchers have sifted through all the data, it is possible that the variant appears to be only 10 to 20 percent more transmissible, said Trevor Bedford, an evolutionary biologist at the Fred Hutchinson Cancer Research Center in Seattle.
Nevertheless, dr. Bedford is likely to catch up fast and become the dominant form in the United States by March. Scientists like dr. Bedford closely monitors all known variants to detect further changes that may change their behavior.
Apart from greater portability, the variant behaves like earlier versions.
The new mutant virus may spread more easily, but in any other way it looks little different from its predecessors.
So far, the variant does not seem to make people sicker or lead to more deaths. After all, there is cause for concern: A variant that is more transmissible will increase the death toll, simply because it spreads faster and infects more people.
“In that sense, it’s just a numbers game,” said Dr. Rasmussen said. The effect is amplified “in places like the US and the UK, where the healthcare system is really at its breaking point.”
The transmission pathways – through large and small droplets, and small aerosolized particles floating in overcrowded interior spaces – have not changed. This means that masks, the time constraint with others and the improvement of ventilation in indoor spaces will help the spread of the variant, as these measures do with other variants of the virus.
“By limiting your exposure to any virus, you will reduce the risk of becoming infected, and this will reduce the transmission in general,” said Dr. Rasmussen said.
Infection with the new variant can increase the amount of virus in the body.
Some preliminary evidence from Britain suggests that people infected with the new variant tend to carry larger amounts of the virus in their noses and throats than those infected with previous versions.
“We are talking in the range between ten times larger and 10,000 times larger,” says Michael Kidd, a clinical virologist from Public Health England and a clinical adviser to the British government who studied the phenomenon.
There are other explanations for the finding – dr. Kidd and his colleagues did not have access to information about when people were tested in their disease, which could affect the so-called viral tax, for example.
The finding does offer one possible explanation for why the new variant spreads more easily. The more virus people are infected in their noses and throats, the more they expel the air and surfaces when they breathe, speak, sing, cough or sneeze.
Consequently, situations that expose people to the virus carry a greater chance of new infections. Some new data indicates that people infected with the new variant are spreading the virus to more of their contacts.
With previous versions of the virus, contact detection has suggested that about 10 percent of people who now have contact with an infected person – within six feet for at least 15 minutes – inhale enough virus to become infected.
“With the variant, we can expect 15 percent of it,” said Dr. Bedford said. “Currently, risky activities are becoming more risky.”
Scientists are still learning how the mutations changed the virus.
The variant has 23 mutations, compared to the version that broke out a year ago in Wuhan, China. But 17 of the mutations appear suddenly after the virus deviated from its youngest ancestor.
Each infected person is a crucible and provides opportunities for the virus to change as it multiplies. With more than 83 million people worldwide infected, the coronavirus accumulates mutations faster than scientists expected at the start of the pandemic.
The vast majority of mutations offer no benefit to the virus and become extinct. But mutations that improve the fitness or transmissibility of the virus have a greater chance of getting caught.
At least one of the 17 new mutations in the variant contributes to its greater infectivity. The mechanism is not yet known. Some data suggest that the new variant may bind more tightly to a protein on the surface of human cells, making it easier to infect.
It is possible that the variant blooms in the nose and throat of an infected person, but not in the lungs, for example – which may explain why patients spread it more easily, but do not get diseases worse than earlier versions of the virus caused not. Some flu viruses behave the same, experts say.
“We must consider this evidence to be preliminary and constructive,” said Dr. Cevik said about the growing data on the new variant.
Yet research so far indicates an urgent need to reduce the transmission of the variant, she added: “We need to be much more careful about everything and look at the gaps in our mitigation measures.”