The Differences Between Every COVID-19 Variant Explained

The COVID-19 virus has been wreaking havoc on the world as we know it for nearly two years. We have collectively hoarded toilet paper, laughed at those who hoarded toilet paper, and made it through everyone saying, "These are unprecedented times!" We've lost loved ones, turned off the news, turned the news back on to stay relevant, and watched as a pandemic has polarized the world. 

One of the most unfortunate things about the pandemic and the COVID-19 virus in particular is that it mutates. From the Delta variant ruining our summer plans to the Omicron variant spreading like wildfire throughout the winter holidays, it has started to feel like there might not be an end in sight. According to the CDC, mutations and variants of the virus are par for the course when it comes to things like this, but that doesn't stop us from wondering how they occur, where one will pop up next, or how dangerous it will be. At this point, the CDC is saying that more variants are expected to crop up in the coming months. For now, here is everything you need to know about some of the most widespread variants of the COVID-19 virus. 

The classification of variants

According to Johns Hopkins Medicine, all RNA viruses mutate and change slowly, which results in divergent strains. Geographical segregation can feed into these different variants. The CDC and the World Health Organization (WHO) classify the many COVID-19 variants into three different categories. 

A variant of interest is loosely defined as a variant that is more easily transmitted than the previous iterations. Variants of interest have often mutated beyond the immunity that has been accrued and can thus become more severe than the previous versions of the virus. 

Variants of concern — of which quite a few have been born of the original COVID-19 virus — tend to be a bit more aggressive in nature than variants of interest. These are often the mutations that cause breakthrough cases or cause re-infection of people who have had the virus or a vaccine. A variant of concern is likely to be transmitted more easily and also can potentially resist antiviral treatments that have worked to thwart earlier versions. 

Finally, variants of high consequences are those that are unbothered by vaccines. Vaccines are unable to protect hosts from sickness when it comes to variants of high consequence. At this time, the COVID-19 virus does not have any variants of consequence (via Johns Hopkins Medicine).


Those in charge are naming COVID-19 variants after letters in the Greek alphabet to help keep them all straight and organized, even though some Greek letters end up with subsets beneath them. Much like the English alphabet, A or Alpha, comes first, which is pretty much what this variant did. The COVID-19 Alpha variant was one of the first variants to surface in 2020, according to Live Science and the WHO. Because it quickly became so widespread and then grew to be the most common mutation of the virus at that time, the CDC named it a variant of concern. 

The Alpha variant was shown to be a bit more aggressive and deadlier than prior versions of COVID-19. The spike protein, which is the structure that influences how the virus interacts with human cells, makes the Alpha variant 30% to 50% more contagious than other versions of the same COVID-19 virus. Before the next strain of the virus became so predominant, the Alpha variant was making up for around 66% of total COVID cases (via Yale Medicine).


Next comes Beta. The Beta variant of COVID-19 was first discovered in South Africa very early on in the global pandemic. A surprising amount of Beta variations were detected in South Africa shortly thereafter. By December of 2020, the Beta variant was named a variant of concern as it had been detected throughout the globe. The Global Virus Network has reported the Beta variant in 48 different countries and at least 23 U.S. states. 

The Beta variant spread in two distinct waves throughout South Africa, with 20% more hospitalizations during the second wave when compared to the first. This variant has eight separate versions and is thought to be about 50% more contagious than the original version of the COVID-19 virus. The Beta variant is another variant that directly affects the spike protein of the virus. In this variant, the spike protein is thought to be a different shape, which inhibits some antibodies from identifying it if it infiltrates the body (via Live Science). 


The people of Brazil, and the city of Manaus specifically, have almost definitely heard of the COVID-19 Gamma variant. This variant has also been called P.1. The strain spread rapidly and infected many people living in Manaus before it spread across the globe. Much like many of the variants that originated in countries across the world, the Gamma variant showed itself to be more easily transmitted than the original COVID virus. In January of 2021, this strain was named a variant of concern by the WHO.

At the time of publication, the Global Virus Network had been unable to produce any evidence to prove that the Gamma variant was any more deadly than the original virus. Though they state that more studies need to be conducted in order to fully prove this. Beyond that, scientists have determined that the Gamma variant is at least two and a half times more contagious and transmissible than the original strain from Wuhan. 


The summer 2021 was marked by the Delta COVID variant, though it was originally detected in India in the latter part of 2020. As the Delta variant spread, it became the most widespread version of COVID and persisted until a new, stronger variant took over in late 2021. The Delta variant has more than a dozen mutations and is still very much on the loose today, despite the emergence of other variants. 

Delta has proven to be super strong and contagious — it even spreads faster than other variants. Comparatively, Yale Medicine reports that it is 80% to 90% more contagious than the Alpha variant. While research is ongoing, it is widely thought that the Delta variant culminates in more severe illnesses (in people who are not vaccinated) than its predecessors. However, Delta has caused many breakthrough cases in vaccinated people, though it is less likely to be fatal for vaccinated populations. The Delta mutations have not been proven to be any more deadly than the original Delta variant, but they are generally more easily transmitted. 


While some variants spread rapidly and take over all news outlets, others peak and then fizzle with nary a whisper of their names. The Epsilon variant was the first variant born on Unites States soil that earned itself recognition as a variant of interest. It originated in California, and after its rapid spread became one of the most prominent strains in the state. In January of 2021, it was thought that the Epsilon variant made up for around one third of total cases in California, according to one study. As of February 2021, the Epsilon variant had been found in at least five other countries, as reported by Very Well Health. Though this strain spread throughout at least 28 U.S. states and was particularly strong on the west coast, the occurrence of it has been predicted to decline. 

There is no conclusive evidence to support that the Epsilon variant caused worse illnesses than other variants, but some people reported reinfection after already having been infected by a different strain. As of midsummer 2021, the World Health Organization stopped tracking the spread of the Epsilon variant. 


The Zeta variant of the COVID-19 virus is another one that, thankfully, didn't catch on and spread around the globe within a matter of days. The Zeta strain was found to be the "the fuel behind Brazil's outbreak in April 2020," according to News Nation Now. This strain became a variant of interest for about six months before being removed from this list.

The CDC added the Zeta strain to its list of variants being monitored (VBM), which is below the list of variants of interest as far as the population is concerned — VBM's are "no longer detected or are circulating at very low levels in the United States." Additionally, the Zeta variant has been found in relatively low numbers in the states, which allows it to be less closely monitored. As such, it poses a much smaller public health risk so is much less concerning to those monitoring each mutation the virus makes. 


The Eta variant of the COVID-19 virus is another iteration in which the spike protein of the virus has mutated. Much like the Alpha strain, this slight change in the protein structure helps the virus evade the antibodies that might already be present in the body. This resistance to antibodies is the main reason why the WHO declared Eta a variant of interest. 

This particular strain was first found in the United Kingdom and Nigeria in late 2020. A mere three months after it was detected, it was named a variant of interest. By the summer of 2021, the Eta variant had been found in 68 countries. Even though this variant spread and mutated semi-quickly, there is not much evidence to show that this variant is more lethal than other versions with similar spike protein mutations. According to Live Science, Moderna released a statement in the summer of 2021 that stated their vaccination provided "slightly less robust [protection] relative to those against the ancestral strain." 


The Iota COVID-19 variant crossed the globe early on in the pandemic, relatively speaking. It originated in New York City and was first discovered in the fall of 2020. Since then, the Iota variant has been found in every U.S. state and at least 50 countries. Stanford Health reported that this mutation accounted for 2% of total sequenced COVID-19 cases in the states, but only 1% worldwide. 

The Iota variant is a tricky one. It has three separate mutations worth noting, all of which influence the way this version of the virus interacts within the human body. Two of the mutations of the spike protein are thought to allow the virus to bind onto human receptor cells with more strength than other variants. However, the CDC states that the Iota variant plays by the rules a little better than other mutations. It has not been shown to cause more severe illnesses than prior versions, though there is concern about its potential to skirt around some immune system structures. In the same report, the CDC noted that the Iota variant has not been linked to re-infections. 


Much like so many other COVID-19 variants, the Kappa strain became well-known by researchers in the fall of 2020 and was thrust onto the variant of interest list in the spring of the following year. Though this variant is widespread, it has only been found in 31 U.S. states. And while it's been found in 52 countries, it only makes up for around 0.5% of sequenced COVID cases, as reported by the Stanford Health dashboard.

The Kappa variant has more mutations than some of the other variants, with seven to eight different ones in the spike protein alone. These mutations allow this virus variant to be more contagious than other variants. In fact, this specific virus structure allows the virus to bind onto human cells more tightly, which increased its transmissibility. The Kappa variant is more resistant to antibodies than other strains and research regarding the efficacy of vaccine antibodies is ongoing, according to Live Science.


Depending on where you live, you may not have heard of the Lambda COVID-19 variant. It was first found in Peru in late summer 2020 and spread rapidly through South American countries. Though it has been detected in 29 countries, Peru has been hit the hardest by this variant. Out of all of the tested COVID-19 cases in Peru, 81% of them showed links to the Lambda variant. Comparatively, this variant was only detected in 31% of cases in Chile, as reported by Live Science.

The Lambda variant has seven different spike protein mutations, all of which influence the way it interacts with the cells of the human body. Some of the mutations in the Lambda variant are thought to increase how easily transmitted it is and to reduce the efficacy of antibody-based treatments. Though there is no current evidence to show that this variant is more deadly and damaging than other versions, it remains firmly cemented on the WHO's list of global variants of interest.


The Mu variant of the virus isn't one that has been widely discussed by American news outlets when compared to Delta and Omicron, though it has spread worldwide with quite a vengeance (via the Mayo Clinic News Network). This strain was initially found in Colombia and spread throughout Central and South America, then onto Europe, and into the United States. The Mu variant is responsible for 39% of sequenced cases in Colombia and 13% of Ecuador's cases, according to Live Science. This variant was also found in 9% of tested COVID cases at one hospital in Miami, FL (via the University of Miami). Ultimately, it only accounts for around 0.1% of sequenced cases globally. 

The Mu variant is closely related to the Beta variant and as such, has the potential to evade the natural immune responses of the human body. In a previous report about the Mu variant, Live Science stated that the real world testing of Mu and how it relates to antibody-laden vaccines is still underway. 


If you are living in the United States right now, the Omicron variant is the real elephant in the room here. It seemed like no one was talking about Omicron until the holiday season and that is mostly because, well, nobody was talking about it. It was first found in November of 2021 in Botswana and South Africa and spread around the world incredibly fast. As of December 2021, Omicron was the most prevalent variant. The rapid spread has led to some countries, the U.S. included, setting travel bans to help #stopthespread in its tracks. 

The Omicron variant contains at least 50 mutations and researchers are still dissecting the ways in which these mutations all work together, as such a mutation has not yet been studied. Omicron is more contagious than Delta, the other main variant that swept across the states, but scientists are still trying to figure out why it is so transmissible. Even without understanding why it is so easily spread, experts are saying that the Omicron variant is likely to become the most widespread variant. 

The severity of Omicron is still being studied. Yale Medicine notes that most of the early reported cases of Omicron were in young people, and that still seems to be the case (via Infection Control Today).

Vaccines and new variants

Omicron threw a wrench into everyone's winter plans by miraculously — or scientifically — spreading to even vaccinated individuals. While this spread and the presentation of illness was to be expected by those who research virus mutations, it has left many vaccinated people confused and searching for answers about whether or not the battery of vaccinations will provide protection against future variants. With this in mind, Johns Hopkins Medicine advises you to keep your eyes on the CDC's guidelines for preventing the spread, infection, and potential re-infections by new strains. 

Ultimately, the research regarding the efficacy of vaccinations on new strains is ongoing. However, Yale Medicine explains that while the effectiveness of vaccines on new strains will decrease, they will still offer some protection by way of antibodies. They state that the severity of infections will be better managed in vaccinated populations, especially those who have received the booster shot. Looking ahead, many vaccine companies are working to create an Omicron-specific vaccine in case such a thing becomes necessary.