A range of SARS-CoV-2 variants has emerged across the world since the COVID-19 pandemic began. Most attention has been on fast-spreading variants recently identified in the UK, South Africa, and Brazil. Scientists suspect that the variants’ particular patterns of mutations have the potential to affect their transmissibility, virulence, and/or ability to evade parts of the immune system. The latter could make people with vaccine-induced or natural immunity to SARS-CoV-2 vulnerable to becoming reinfected with novel variants, and these possible effects remain under investigation.
There are a handful of other variants—typically with fewer eye-catching mutations—that researchers are also keeping a close watch on, notes molecular epidemiologist Emma Hodcroft of the University of Bern in Switzerland. Making matters confusing, scientists can’t agree on a standardized naming system for new variants, causing what one researcher has called a “bloody mess” of nomenclature.
Here The Scientist compiles a summary of some noteworthy variants recently associated with rapid spread that US researchers are currently monitoring.
Potential effects on transmissibility, virulence, and immune escape
B.1.1.7, 20I/501Y.V1, VOC202012/01
First identified in late December in the UK, it has spread to 62 countries in Europe, Asia, the US, and elsewhere.
17 recent mutations, including N501Y, P681H, HV 69–70 deletion, and four more on the spike protein; the ORF8 Q27stop mutation outside the spike protein
• Thought to have greater than 40 percent increased transmissibility
• Increased virulence suggested but remains unresolved
• Little concern around current vaccine efficacy
Identified in late December in South Africa and now spotted in Africa, Europe, Asia, and Australia
21 mutations, including N501Y, E484K, and K417N on the spike protein, and ORF1b deletion outside the spike protein
• Suggested to have heightened transmissibility
• No evidence of increased virulence
• In vitro studies suggest a potential for immune escape following natural infections and a small effect on the potency of vaccine-induced antibodies
Discovered in travelers from Brazil during screening at a Japanese airport in January; now known to widely circulate in Brazil’s Amazonas state and also observed in the Faroe Islands, South Korea, and the US
17 amino acid changes, including N501Y, E484K, and K417N on the spike protein; ORF1b deletion outside the spike protein
• Effect on transmissibility and/or virulence unknown
• Anecdotes of reinfections reported, but potential for immune evasion remains unresolved
Two cases of the N501Y mutation have been detected in Columbus, Ohio, since late December, and in other US states since
N501Y, located in the virus’s spike protein. It lacks most other mutations present in the B.1.1.7 variant identified in the UK.
• No evidence yet of altered transmissibility, virulence, and/or immune evasion
S Q677H, sometimes called “Midwest” variant
Viruses containing the S Q677H mutation have recently become frequent in samples analyzed during December and January in Ohio, and have also been found in multiple Midwest states
Q677H mutation on the spike protein, A85S on the M protein, and D377Y on the nucleocapsid protein
• So far, no evidence of altered transmissibility, virulence, and/or immune evasion
The L452R mutation itself was observed in the US and Europe last year. In January 2021, it rose rapidly in frequency in multiple California counties.
L452R mutation, located on the spike protein
• Associated with several large outbreaks in California, but it remains unclear if the surges are driven by the variant itself
• Effects on vaccine efficacy under investigation