The highly contagious British variant of the Covid-19 virus, now the dominant virus strain in the United States, makes the pandemic more difficult to control. But it also comes with a silver lining: The approved vaccines work well against it.
The variant, called B.1.1.7, is better able to take advantage of dropout in mask wearing and social distance and requires more people to develop an immune response to slow it down. Still vaccines from Pfizer Inc.
and its partner BioNTech SE,
and Johnson & Johnson,
along with security measures, they remain effective, and health officials say the shots are beginning to slow down Covid-1
“If we did not have this background of vaccination, we would be completely overwhelmed right now,” said Joshua Schiffer, an associate professor in the Vaccine and Infection Section at the Fred Hutchinson Cancer Research Center. The increased infectivity of the virus “makes it much, much harder to contain,” he said.
The B.1.1.7 variant first appeared in the UK at the end of last year, spurring a deadly new rise in cases and a new round of severe lockdowns. It jumped to several other countries, including the United States, where it quickly became the most common viral variant. Nearly 60% of Covid-19 cases in the United States could be attributed to the variant in early April, according to data from the Centers for Disease Control and Prevention.
A study published in March in the journal Science suggested that B.1.1.7 was within a range of 43% to 90% more infectious than pre-existing variants. With a more contagious variant, each person can, on average, transmit the virus to more people, exacerbating the spread of the virus.
B.1.1.7’s increased infectivity is one of the reasons why health authorities continue to encourage people to keep up with measures such as Wearing a mask, social distance or sticking to outdoor activities until more people are fully vaccinated and cases fall. About 39% of American adults are fully vaccinated, the CDC says.
“With an older variant, you might have been in that transmission chain and transmitted to another person. Now you may be sending to 1.5 or 1.7 other people, and then if you can cut the transmission chain, you will have an even greater effect, ”said Emma Hodcroft, a molecular epidemiologist at the University of Bern in Switzerland. “The role of the broken joint that stops the transmission chain is even more important.”
The proportion of people who need an immune response from vaccination or previous infection to slow the spread of the virus also increases when a virus is more contagious, infectious disease experts say.
The variant has several mutations that distinguish it from previous versions of the virus, including some that affect its tip protein – a structure that sits on the virus’ surface and helps it bind to human cells. All of the approved vaccines in the United States target the spike protein and are designed to mount defenses against it and are all still effective against the B.1.1.7 variant despite its mutations. At least one laboratory-based study found that the variant does not increase the risk of reinfection either.
“The good news is that the vaccines are effective against B.1.1.7,” said Mary Jo Trepka, an infectious epidemiologist at Florida International University. “There’s even more reason why we want to get people vaccinated and want them to be vaccinated now.”
Last week, the CDC further eased its guidelines for fully vaccinated people, saying they do not need to wear masks in certain situations. The current seven-day average of cases is just over 52,500, which is a decrease of approx. 16% from the previous seven days, and hospital admissions have dropped nearly 10%, CDC director Rochelle Walensky said Friday.
“With 100 million Americans fully vaccinated today, we continue to move forward in our progress to end this pandemic,” said Dr. Walensky.
Other coronavirus variants that researchers have marked as a concern have also been identified in the United States, including those that first emerged in Brazil and South Africa, as well as variants originating in the United States.
The varieties from Brazil and South Africa, called P.1. and B.1.351, respectively, have so far not gained a strong foothold in the United States, and some infectious disease experts say that dominance of B.1.1.7 may make it more challenging for these variants to spread.
It is likely that B.1.1.7 arrived in the United States before these other variants of concern, and early super-spreader events could have helped it spread and outcompete them, said Dr. Schiffer. However, the new variant conditions vary according to condition. Eg. P.1. variant accounts for 14.3% of cases in Illinois.
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Researchers say public health authorities need to be aware of new variants. If a population has partial immunity but does not run cases down, variants that can better avoid immune systems, such as B.1.351, can gain an advantage, virologists say.
Additional variants of concern are also likely to arise as Covid-19 cases increase globally. Researchers are collecting data on whether the vaccines are effective against the variant that recently emerged in India. However, a laboratory-based study that has not yet been peer-reviewed suggests that India’s Covaxin vaccine is capable of neutralizing the variant.
However, some drug manufacturers are working on vaccine updates targeted at some of the newer variants, and researchers say that variants can also be brought under control with the now well-known public health measures.
“They have not developed superpowers. They do not scratch through anyone’s mask, ”said Dr. Hodcroft and referred to viral variants. “Many of the things we have in place right now that we followed can be effective.”
—Daniela Hernandez and Denise Blostein contributed to this article.
Write to Brianna Abbott at email@example.com
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