A Comprehensive List of All of the COVID-19 Variants and How They Compare, Per Doctors
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The coronavirus has come a long way since 2020. While the days of sanitizing Amazon packages and standing six feet apart may feel like they’re behind us (and they very well may be), the SARS-Co-V-2 virus (which causes COVID-19), continues to evolve. With Alpha, Delta, Omicron, and more iterations, it’s normal to wonder how many COVID variants are there? Ahead, experts explain the evolution of COVID-19, and the latest variants of concern.
Meet the experts: Linda Yancey, M.D., an infectious diseases specialist at Memorial Hermann Hospital; and Peter Kasson, M.D., Ph.D., B.S., of University of Virginia’s departments of Molecular Physiology and Biomedical Engineering.
What is a COVID variant?
A variant is just a slightly changed virus, Linda Yancey, M.D., an infectious diseases specialist at Memorial Hermann Hospital says. “Viruses go through generations just like people do. And like people, each virus generation is a little different from the one that came before,” she says. In the case of COVID-19, the virus has mutated multiple times, leading to variants like Alpha and Delta, and various subvariants of Omicron.
“Variants that can infect people better or evade immunity to the last variant are more likely to cause a new COVID wave,” Peter Kasson, M.D., Ph.D., B.S., of the University of Virginia’s departments of Molecular Physiology and Biomedical Engineering says. “Variants that are different enough, or concerning enough, sometimes get special names.” Examples of this include Alpha, Beta, Delta, and Omicron. Variants are further broken down into subvariants with labels like EG.5, or “Eris,” or XBB.1.16.6—both are subvariants of Omicron.
Why do variants develop?
Viruses like SARS-CoV-2 and influenza carry their genetic code in RNA (ribonucleic acid, a nucleic acid present in all living cells), Dr. Kasson says. “When more RNA is made, there is a certain chance that the copy will not be perfect and a mutation will occur,” Dr. Kasson says. “Since millions of people are getting COVID, there are a lot of chances for mutations.”
The concept of a “variant” comes from the same idea as a “strain,”—it’s just a difference in the viral genome, Dr. Kasson says. Most mutations either make the virus “infect worse or have no effect,” Dr. Kasson says, but some make the virus infect people more efficiently or help it evade existing immunity—a.k.a. make it harder for vaccines to protect against infection. “These mutations have a chance to spread further,” Dr. Kasson says.
How many COVID variants are there?
So far, there have been four major variants: Alpha, Beta, Delta, and Omicron. Some of these contain multiple subvariants, though, each with their own name. The most prominent variants of COVID-19 include:
Omicron (including subvariants)
Omicron constitutes the current strain of COVID-19 in circulation. “Omicron is very contagious. That was how it out-competed the Delta variant,” Dr. Yancey says. Omicron’s subvariants continue to evolve, leading to even more iterations of the variant. Dr. Kasson says that the current vaccines cover “a pretty broad range of variants, and vaccines against some of them don’t necessarily protect against all,” he says. “Current Omicron subvariants can infect fairly quickly, so the current vaccine does less well than we’d like at preventing infection altogether. But it still helps with this, and it’s fairly effective at preventing severe illness and death. That’s why doctors recommend getting it.”
Dr. Yancey says the current COVID boosters are “highly effective” against EG.5 and HV.1.
Major subvariants at this time in the US, according to Dr. Kasson, are:
Delta
COVID-19 variant Delta was less contagious than Omicron and is not currently circulating, explains Dr. Kasson. Though Delta caused about twice as many infections as its predecessors, according to Dr. Yancey, it wasn’t as contagious as Omicron. But, there is evidence to suggest it caused more severe disease than its predecessors. A Lancet report noted that those infected with COVID-19 in England had double the hospitalization risk with Delta than Alpha.
Thankfully, current vaccines are “very effective at protecting against Delta,” Dr. Yancey says.
Major subvariants at this time in the US, according to Dr. Yancey, include:
Beta
Beta was about twice as contagious as the original COVID strain, Dr. Yancey says. “Since the strain only circulated for a few months at the beginning of 2021, we don’t have a lot of information about vaccine prevention. It had been outcompeted by the time the vaccines became widely available.” She notes that the variant was not seen often in the US.
Beta was less contagious than Delta or Omicron and is not currently circulating, according to Dr. Kasson.
Beta had no special variants, according to Dr. Yancey.
Alpha
Alpha appears to have been only mildly more contagious than the original strain though it did cause a more severe disease. It had a variant called B.1.1.7 that caused more severe disease. Alpha circulated from late 2020 to late 2021 before it was outcompeted by Delta and then Omicron. Our current vaccines are effective against it.
Alpha was less contagious than Beta, Delta, or Omicron and is not currently circulating.
“To my knowledge, protection in people has not been tested for the older variants and the new vaccines simply because we don’t intentionally give people COVID and those variants aren’t circulating. For people who were vaccinated against or exposed to older variants, vaccination against new variants also helps boost those older responses and should provide protection,” Dr. Kasson says.
Subvariants of note include, according to Dr. Yancey:
This story is accurate as of press time. For a full list of the latest COVID-19 variants, check the World Health Organization’s SARS-CoV-2 variant tracker.
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