Mutations happen randomly in all living things. And depending on the type of organism, some or all of those mutations are passed down to the next generation. Those generations come very quickly in viruses. (Viruses aren’t technically living, but it’s the same idea.) Some of these mutations actually make the virus worse at infecting people, and they fizzle out. Many mutations are neutral. But some benefit the virus, allowing it to spread faster in humans, such as by becoming more transmissible or better at evading the COVID vaccines.Currently, there are two so-called “variants of concern” and 10 “variants being monitored” by the U.S. government SARS-CoV-2 Interagency Group (SIG). However, there are many more variants that health officials aren’t especially worried about.As long as COVID is circulating, it’s going to keep mutating, and new variants will pop up. Large populations of unvaccinated people make it more likely for these variants to evolve, so go get your shot!

Types of COVID Variants

Some variants are considered variants of interest. These variants could be worse than the original coronavirus, but health authorities aren’t quite sure yet. They might have genetic markers that could change transmission, diagnostics, treatment, or the virus’ ability to evade the immune system. Or they may be suspected to cause more severe disease or increased transmissibility. But these variants aren’t prevalent. In other words, the authorities are tracking these variants because they could potentially become a problem, but they aren’t an issue at the moment. There are currently no variants of interest as classified by SIG. As a step up, the SIG classifies some variants as variants of concern. There is evidence that these variants are worse for diagnostics, treatments, or vaccines, or that they’re more transmissible or cause more severe disease. Basically, they’re confirmed as more dangerous, although they may or may not be widely prevalent. There are also variants of high consequence, which are the top tier scary variants. Luckily, none have been identified yet. To reach this level, there would have to be “clear evidence that prevention measures of medical countermeasures… have significantly reduced effectiveness relative to previously circulating variants.” Yes, this type of variant would have to be worse than Delta and Omicron.So which variants do you actually need to worry about? Here is your cheat sheet to every variant on the U.S. watchlist right now.

Variants of Concern:

Delta

What to Know: It’s more than twice as transmissible as the original coronavirus. Antibody treatments and vaccination may be less effective against it.First Identified In: India in October 2020Where It Is Now: Delta is still circulating, but in many countries, Omicron has replaced it as the dominant variant.

Omicron

What to Know: Omicron is potentially four times more transmissible than Delta but generally causes less severe disease than previous variants. Vaccines and monoclonal antibody treatments are less effective against it, and Omicron is better at evading immunity than Delta.First Identified In: Multiple countries in November 2021Where It Is Now: Omicron is now the dominant variant in the U.S. and many other countries. Recently, BA.2 (“stealth Omicron”) has begun to overtake BA.1.

Variants Being Monitored:

Alpha

What to Know: Compared to the original coronavirus, it’s about 50 percent more transmissible, and it may cause more severe disease. Convalescent therapy and vaccination may be minimally impacted.First Identified In: U.K. in September 2020Where It Is Now: Few cases are currently being reported.

Beta

What to Know: Compared to the original coronavirus, it’s about 50 percent more transmissible. One type of antibody treatment is significantly less effective against it, and convalescent therapy and vaccination are less effective against it.First Identified In: South Africa in May 2020Where It Is Now: Few cases are currently being reported.

Gamma

What to Know: One type of antibody treatment is significantly less effective against it, and convalescent therapy and vaccination are less effective against it.First Identified In: Brazil in November 2020Where It Is Now: Few cases are currently being reported.

Epsilon

What to Know: It may be more transmissible, and vaccination may be less effective against it.First Identified In: California in July 2020Where It Is Now: Few cases are currently being reported.

Eta

What to Know: Antibody treatments, convalescent plasma therapy, and vaccination may be less effective against it.First Identified In: U.K. and Nigeria in December 2020Where It Is Now: Few cases are currently being reported.

Iota

What to Know: Less susceptible to a certain type of antibody treatment. Convalescent plasma therapy and vaccination may be less effective against it.First Identified In: New York in November 2020Where It Is Now: Few cases are currently being reported.

Kappa

What to Know: Some antibody treatments and vaccination may be less effective against it.First Identified In: India in December 2020Where It Is Now: Few cases are currently being reported.

B.1.617.3

What to Know: Some antibody treatments and vaccination may be less effective against it. Listed by the CDC but not by the WHO.First Identified In: India in October 2020Where It Is Now: Few cases are currently being reported.

Zeta

What to Know: It may have been more likely to cause reinfection.First Identified In: Brazil in April 2020Where It Is Now: Few cases are currently being reported.

Mu

What to Know: Vaccination may be less effective against it. Recently listed by the WHO, but not by the CDC.First Identified In: Colombia in January 2021Where It Is Now: Few cases are currently being reported.

This story is developing. We will update it as soon as new information becomes available.