A New Strain of the Coronavirus Is Spreading: Here’s What We Know

Please note, this article was updated on 1/22; information on SARS-CoV-2 variants continues to evolve.

A new strain of SARS-CoV-2 is now circulating globally, leading to stricter lockdown restrictions abroad. With vaccine distribution efforts underway, scientists are working to monitor the spread of this strain, characterize emerging variants and understand their potential impact on vaccine-induced immunity.

Researchers are referring to this strain, a variant with a demonstrably different phenotype, as B.1.1.7. It was first discovered in the United Kingdom and has been circulating since fall 2020, according to the CDC. It has already spread to the U.S., Canada and other countries worldwide.

Researchers have distinguished it from B.1.3.5., a variant of concern (VOC) detected outside of South Africa. Although it does share some key mutations, or changes in the sequencing, it was thought to have emerged independently of the B.1.1.7 lineage. Researchers are also watching other emerging strains, including P.1, identified in Brazilian travelers in Japan, and CAL.20C, a strain in Los Angeles County. Another potential VOC was recently identified in Columbus, Ohio, with three other mutations that have not yet been reported; these findings are currently under review.

“It’s characteristic of RNA-based genomes, like coronaviruses and the human immunodeficiency virus, to mutate. This is part of their evolutionary strategy,” explains Steven Gordon, MD, Chairman of Cleveland Clinic’s Department of Infectious Disease. “What is potentially more concerning is that the B.1.1.7 lineage is more transmissible than what we’ve seen previously with this virus.”

Findings: More contagious, but not more virulent

The B.1.1.7 lineage is estimated to be 56% more transmissible than its predecessor strain, according to a new report. A team of British researchers describes key genetic changes, including three mutations in the spike protein, that have biological significance. One of these mutations has shown a binding affinity for the ACE2 receptor, the known viral entry point for SARS-CoV-2, in humans and in mouse models.

“At this time there is no evidence that suggests this strain is more virulent or leads to increased morbidity or mortality,” notes Dr. Gordon. But its transmissibility is worrisome, especially with known cases in several countries. “The horse is out of the barn on this strain, so to speak.”

Scientists are also concerned that new strains could potentially evade detection by a diagnostic test or become resilient to vaccine-induced immunity.

Dr. Gordon notes that most commercially available PCR tests have multiple pathogenic targets, so if a mutation alters the spike protein, for example, the virus should still be detected — even if the assay cannot distinguish the specific variant.

There is also no evidence currently that suggests the new strain is able to evade immunity of the two FDA-authorized vaccines. Because the vaccines are polyclonal — meaning they provide antibodies that target several parts of the spike protein — the virus would have to undergo multiple mutations of the spike to become vaccine-resistant.

Experts are monitoring its spread, reinforcing precautions

The CDC recently launched the SARS-CoV-2 Strain Surveillance program to monitor this new strain and emerging VOCs. Each state will send in samples biweekly that will undergo sequencing and analysis by the CDC.

While scientists and public health officials monitor new developments, Dr. Gordon stresses the importance of continued efforts to mitigate the spread of the virus. “Masking, hand hygiene and physical distancing are still essential,” he says.

Ultimately, he forecasts that widespread vaccine distribution, in addition to these nonpharmacological interventions, will put an end to the pandemic. Adding with encouragement, he remarks, “I am hopeful; with access to an effective vaccine, we’ve now entered a new era.”