READ THIS NEXT: Dr. Fauci Warns It’s “Very Clear” Vaccinated People Need to Do This Now. The original Omicron variant lost steam in Feb. 2022, allowing cases to fall significantly. But the most recent uptick in infections is not the result of the original Omicron, BA.1. The dominant variant in the U.S. right now is actually BA.2, which is a subvariant of Omicron, according to the CDC. And as New York Magazine recently explained, there are now at least four Omicron subvariants circulating the country: BA.2, BA.2.12.1, BA.4, and BA.5. While BA.2 is still the dominant variant in the U.S., another Omicron subvariant is quickly rising up and causing concern among virus experts. According to the CDC, the BA.2.12.1 subvariant is currently estimated to be causing 42 percent of infections in the country right now. Many experts say this subvariant is posed to become the dominant variant in the U.S. very soon, as it has already dominated certain parts of the country, like the state of New York. “This subvariant [is] unbelievably transmissible,” Peter Hotez, MD, an infectious disease expert and vaccine researcher at Baylor College of Medicine, warned in a series of tweets on May 14. In an interview with ABC-affiliate KTRK in Houston, Texas, Hotez added: “BA 2.12.1 is the mother of all variants in terms of transmissibility. It’s getting up there with measles. Have respect for it because it can come and get you.” RELATED: For more up-to-date information, sign up for our daily newsletter. While many virus experts, including White House COVID adviser Anthony Fauci, MD, have previously said that an uptick in cases doesn’t necessarily mean the U.S. is headed toward another surge, others are now warning that optimism might no longer be warranted. “What may seem like a speed bump actually can turn into a big wave,” Katelyn Jetelina, PhD, an epidemiologist and assistant professor at the University of Texas Health Science Center, recently told the Houston Chronicle. In fact, the rise of the highly infectious BA.2.12.1 subvariant is likely to cause another “full-on wave,” Hotez warned in another tweet. According to the infectious disease expert, this upcoming surge is poised to hit the U.S. over the summer. “Looks to me like we’re heading towards a full-blown wave that could be almost as significant as Omicron in terms of the number of new cases,” Hotez told KTRK. If you caught the original Omicron variant this past winter, you might assume you’re safe from its emerging subvariants. But experts say this is probably not the case—especially if you’re unvaccinated. “A lot of Omicron-infected people who chose not to vaccinate on top of that are all now getting [BA.2.12.1] reinfection,” Hotez told WBUR, the National Public Radio (NPR) news station in Boston.ae0fcc31ae342fd3a1346ebb1f342fcb In his May 14 tweets, Hotez noted that only about 30 percent of all Americans are vaccinated and boosted. The infectious disease expert says that you should “max out your vaccinations while we still have vaccine inventory.” This means getting vaccinated if you aren’t, getting your booster if you’re vaccinated but not boosted, and getting a second booster if you’re eligible for it. “Our nation is way under-vaccinated, only 100 million Americans are vaccinated and boosted,” he said. “Also Omicron is not providing durable or strong protection. We are incredibly vulnerable to this BA.2.12.1 wave.” READ THIS NEXT: Doctor Issues Major New Warning to All Americans—Including the Vaccinated.