The highly contagious variant of the Covid-19 virus in the United Kingdom, which is now the dominant strain of the virus in the United States, makes the pandemic more difficult to control. But it also comes with a silver lining: permitted vaccines work well against it.
Option called B.1.1.7 is better able to use mask gaps and social distancing and requires more people to develop an immune response to slow it down. Still vaccines from Pfizer Inc.
and its partner BioNTech SE,,
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along with precautions, remain effective and health authorities say the shots are starting to slow down Covid-1
“If we hadn’t had this vaccination attempt, we would be completely crushed right now,” said Joshua Schiffer, an associate professor in the Department of Vaccines and Infectious Diseases at the Fred Hutchinson Cancer Research Center. The increased infectivity of the virus “makes it much, much harder to maintain,” he said.
Option B.1.1.7 first appeared in the UK at the end of last year, causing a deadly new jump in cases and a new round of strict blockades. It has spread to several other countries, including the United States, where it has quickly become the most common viral variant. Nearly 60% of Covid-19 cases in the United States could be attributed to the variant by early April, according to data from the Centers for Disease Control and Prevention.
A study published in March in the journal Science suggests that B.1.1.7 is in the range of 43% to 90% more contagious than existing variants. With a more infectious variant, each person, on average, can transmit the virus to more people, worsening the spread of the virus.
The increased infectivity of B.1.1.7 is one of the reasons health authorities continue to urge people to observe precautions such as wearing masks, social distancing or adhering to outdoor activities until more people are fully vaccinated and the cases are eliminated. About 39% of adults in the United States are fully vaccinated, says the CDC.
“With an older version, you may have been in this chain of transmission and transmitted to another person. You can now transmit to 1.5 or 1.7 other people, so if you can break this transmission chain, you will have an even greater effect, “said Emma Hodcroft, a molecular epidemiologist at the University of Bern, Switzerland. “The role of being that broken link that stops this transmission chain is even more important.”
The proportion of people who need to have an immune response from vaccination or a past infection to slow the spread of the virus also increases when the virus is more contagious, infectious disease experts say.
The variant has several mutations that distinguish it from earlier versions of the virus, including some that affect its protein, a structure that sits on the surface of the virus and helps it attach to human cells. All authorized vaccines in the United States target the protein with spikes and are designed to mount protective forces against it and are still effective against variant B.1.1.7 despite its mutations. At least one laboratory study found that the option also did not increase the risk of re-infection.
“The good news is that vaccines are effective against B.1.1.7,” said Mary Joe Trepka, an infectious disease epidemiologist at the International University of Florida. “That’s an even bigger reason why we want to vaccinate people and want them to be vaccinated now.”
Last week, the CDC further eased its guidelines for fully vaccinated people, saying it was not necessary to wear masks in certain situations. The current seven-day average incidence rate is just over 52,500, down about 16 percent from the previous seven days, and hospitalizations have dropped by nearly 10 percent, CDC Director Rochelle Valenski said on Friday.
“With 100 million Americans fully vaccinated to date, we continue to make progress in ending this pandemic,” Dr. Valensky said.
In the United States, other variants of the coronavirus have been identified that scientists have noted as a concern, including those first appearing in Brazil and South Africa, as well as variants originating in the United States.
The options from Brazil and South Africa called P.1. and B.1.351, respectively, have not yet been strongly established in the United States, and some infectious disease experts say that the dominance of B.1.1.7 may make the spread of these variants more challenging.
It is likely that B.1.1.7 arrived in the United States before these other forms of concern, and early events of super-spread may have helped it spread and compete, Dr. Schiffer said. However, the new proportions of the option differ depending on the country. For example P.1. the option represents 14.3% of cases in Illinois.
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Scientists say public health authorities need to pay attention to the new options. If a population has partial immunity but does not reduce the incidence, options that may better evade immune protection, such as B.1.351, may gain an advantage, virologists say.
Additional options for concern will also emerge as Covid-19 cases increase worldwide. Researchers are collecting data on whether vaccines are effective against a variant that has recently appeared in India. But a laboratory study that has not yet been reviewed suggests that the Covaxin vaccine in India is able to neutralize the variant.
Some drugmakers are working on vaccine updates targeting some of the newer options, and scientists say the options can be brought under control with already known public health measures.
“They have not developed superpowers. They don’t make their way through anyone’s mask, “said Dr. Hodcroft, referring to the viral variants. “A lot of the things we have right now that we’re following can be effective.”
—Daniela Hernandez and Denise Blostein contributed to this article.
Write to Brianna Abbott at firstname.lastname@example.org
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