The Delta Variant is one of several new strains of SARS-CoV-2 recently added the variant zoo. Why has this new variant received so much attention lately, and why are we referring to variants with Greek letters now?
The CDC still groups variants into categories of High Consequence, Concern, and Interest. Thankfully, there are still no Variants of High Consequence. The WHO has assigned Greek letters to certain variants to aid in communication. The Delta Variant, B.1.671.2, is a new entry on the list of Variants of Concern. Three cousins of the Delta Variant, B.1.671, B.1.671.1 and B.1.671.3 are now on the Variants of Interest list. All these new strains originated in India.
What makes Delta different? It’s the first addition to the Variant of Concern list since April, and it’s prevalence in the U.S.is increasing. Although it’s not nearly as prevalent as the Alpha Variant, aka the U.K. Variant, B.1.1.7 which we first learned about last December, some reports suggest that the Delta Variant is even more easily transmitted, meaning that it may soon replace the Alpha Variant as the most common form in the U.S. The Delta Variant shows some resistance to treatments, although not more than other variants. It does not escape detection by tests, and S-antibodies, either from disease or vaccine, seem to provide immune protection. The Delta Variant is just the ‘new kid on the block’; we need to take this in stride.
I’ve updated variant reference tables, sorted by U.S. prevalence.
| Variants of Concern | |||||||
| Variant | WHO Label | First Detection | Current U.S. Prevalence | Increased Transmission | Increased Severity | Reduced Detection by Tests | Resistance to Treatment |
| B.1.1.7 | Alpha | UK | 69.7% | 50% | ● | ||
| P.1 | Gamma | Japan/Brasil | 8.4% | ● | |||
| B.1.617.2 | Delta | India | 2.7% | 140% | ● | ||
| B.1.351 | Beta | South Africa | 0.7% | 50% | ● | ||
| B.1.429 | Epsilon | California | 0.6% | 20% | ● | ||
| B.1.427 | Epsilon | California | 0.4% | 20% | ● |
| Variants of Interest | |||||||
| Variant | WHO Label | First Detection | Current U.S. Prevalence | Increased Transmission | Increased Severity | Reduced Detection by Tests | Resistance to Treatment |
| B.1.526 | Iota | New York | 5.0% | ● | |||
| B.1.526.1 | New York | 2.5% | ● | ||||
| B.1.525 | Eta | UK/Nigeria | 0.1% | ● | |||
| B.1.617.1 | Kappa | India | 0.1% | ● | |||
| P.2 | Zeta | Brazil | 0.0% | ● | |||
| B.1.617 | India | 0.0% | ● | ||||
| B.1.617.3 | India | 0.0% | ● |
