Nearly 65% of the US population is now fully vaxxed against COVID-19. And about 43% of those fully vaxxed have gotten their booster shot. But one lesson we’ve learned with both Delta and Omicron: variants can cause a major hitch in medical care and treatments, travel, and even the reopening of economies. While Omicron is the latest COVID-19 variant — and is known for how transmissible it is — it is not the last. Recently, scientists discovered that Omicron has spawned a number of subvariants (yes, that it is a thing) — learn more about them below. How Variants and the Newest Omicron Variant Work Variants happen when a virus’s genes change or mutate. The word ‘mutate’ might sound scary, but it’s actually normal. As the virus spreads, it makes copies of itself. And sometimes, not all of the same instructions make it into the new copy. So it becomes a different version (aka a new strain or variant). Typically mutations aren’t a big deal because they don’t always change how a virus behaves. The variant still making headlines in early 2022 is Omicron. Aka B11529. Like other major variants, it made the CDC’s list of “variants of concern.” Here’s what we know about it (so far): Omicron was first flagged in South Africa in November. But it likely reached the Netherlands first. Meaning: It was probably in Western Europe earlier than experts thought. After just a few weeks, it became the dominant strain in the US. Accounting for nearly 100% of daily cases as of Feb. 22. It’s also been detected in more than 165 nations around the world. Omicron is more transmissible than previous variants, and has 53 mutations to its spike protein — setting it apart from the original coronavirus strain. Mild symptoms have typically been associated with this variant (think: similar to a cold such as coughing, fatigue, headache, etc.) And while vaccines help prevent severe illness against the variant, it can evade antibodies easier than previous variants. Meaning, breakthrough infections are more common. Omicron’s peak appears to have passed in the US. And the number of COVID-related deaths have started falling. But it’s unclear if or when the variant will be less prevalent. There’s also Omicron’s sketchy sibling. Aka BA.2 or “stealth” subvariant. When Omicron was first detected, scientists determined that it had multiple versions: BA.1 (the one we first found out about), BA.2, and BA.3. And over the past month, BA.2 started to make headlines across the globe. It’s become the dominant strain in at least 10 countries. And accounts for almost 4% of cases in the US, as of Feb. 22. Early reports indicate that BA.2 could be 1.5 times more transmissible than BA.1 (hence stealth). And preliminary data out of Japan shows it could result in more severe illness. But there’s still a lot to learn about this subvariant. Experts are keeping a close eye on how it holds up against vaccines and boosters. Remember: Variants are normal. And health experts urge caution as the virus continues to mutate and spread. They recommend getting vaxxed. As well as getting back to basics (think: wash your hands, mask up). Actions that may help the virus develop from a pandemic to endemic. Other Variants to Know About, From Alpha to Delta Four other variants that have been on people’s radars since the start of the pandemic are… Alpha. Aka B117. It was first detected in September 2020 in the UK. And was previously the dominant strain in the US in 2021. It’s believed to be about 50% more contagious and could potentially cause more severe illness. Experts say that the vaccines currently available offer good protection against Alpha. Beta. Aka B1351. It first emerged in October 2020 in South Africa. And it’s about 50% more transmissible, and there were concerns that vaccines may not be as effective when it comes to this variant. Researchers have found that the variant includes mutations that may make it easier for it to evade antibodies. Though it seems the current vaccines fared fine against the variant. Gamma. Aka P1. This variant was detected in January 2021 after four travelers went from Brazil to Japan. Similar to the Beta variant, Gamma has mutations that may help it evade antibodies generated by a COVID-19 infection or vaccine. Delta. Aka B.1.617.2. It was first detected in October 2020 in India. And contributed to the devastating surge of infections there in mid-2021. It was the dominant strain in the US until Omicron came on the scene. But the CDC still has it labeled as a “variant of concern.” theSkimm Variants are a common occurrence for any virus. And while the US is still in the thick of it with COVID-19, it's more important than ever to stay up-to-date with the latest science on new variations of the disease. Check back here for updates on the latest variants affecting the US. And to stop the spread, practice the basics and learn more about available vaccines. Updated on Feb. 22 to include the latest info about the BA.2 variant. Updated on Jan. 31 to include details about the new Omicron variants.