READ THIS NEXT: Dr. Fauci Warns All Americans “Need to Pay Attention” to This Now. COVID numbers aren’t just having a surprising surge with no explanation. A new version of Omicron is taking hold of the U.S., pushing infections, hospitalizations, and deaths back up. The BA.5 Omicron subvariant recently became the dominant variant in the country, overtaking the previously dominant subvariant BA.2.12.1 in just around two months, per the CDC. The agency’s latest data indicates that BA.5 is now estimated to be responsible for 65 percent of new COVID cases in the U.S. “We do not know yet about the clinical severity of BA.4 and BA.5 in comparison to our other Omicron subvariants, but we do know it to be more transmissible and more immune evading,” CDC Director Rochelle Walensky, MD, said during a White House press briefing on July 12. According to top White House COVID adviser Anthony Fauci, MD, BA.5 has a “growth advantage” over the prior Omicron subvariants that allows it to “substantially” evade immunity produced by both vaccination and infection. This means that people with prior infection—even from the original Omicron variant BA.1 or earlier subvariants like BA.2—are still at risk for reinfection from the newly dominant subvariant. “If you were infected with BA.1, you really don’t have a lot of good protection against BA.4 or 5,” Fauci said during the July 12 briefing. “And in other countries, particularly, that have BA.4, 5 antedating ours, the reinfection rate is clear that that’s the case.” During a July 17 interview on ABC’s This Week, White House COVID response coordinator Ashish Jha, MD, confirmed that BA.5’s ability to evade immunity is allowing people who were infected with COVID just three or four months ago to get it again. “We’re seeing high levels of reinfection. We’re seeing people who are not up to date on their vaccines have a lot of breakthrough infections,” Jha warned. RELATED: For more up-to-date information, sign up for our daily newsletter. Virus experts are still pushing vaccinations amid the immune-evasive BA.5 variant. Even with the variant’s ability to get past many defenses, vaccines still produce protection against infection for people up-to-date with their shots, according to Jha. More importantly, he said vaccines still keep people safe from severe illness. But this protection only stays strong for so long—which is why virus experts are cautioning more vulnerable individuals to look at when they last received a COVID shot. “If you got your booster, let’s say, last November or December, you don’t have as much protection against this virus as you’d like,” Jha explained. “So one of the key messages coming out of this moment is, if you are 50 or over and if you have not gotten a shot this year, in the year 2022, it is absolutely critical that you go out and get one now. It will offer a very high degree of protection.” Since March, all Americans 50 and older have been eligible for a second COVID booster shot. During the White House press briefing, Walensky warned that “many Americans are under-vaccinated,” which includes a large number of those over the age of 50 who are not up-to-date on their booster shots. About 100 million Americans have gotten their first booster, but only 28 percent of those over 50 have received a second booster dose, according to Walensky.ae0fcc31ae342fd3a1346ebb1f342fcb This is especially concerning due to the fact that CDC data shows that among those 50 and older, people who have only gotten one booster had four times the risk of dying from COVID than those who have had two or more booster shots. And while some older adults might be trying to wait for Omicron-specific booster shots to be released this fall, experts are cautioning against this. “I’m recommending, everybody over 50, if you’ve not gotten a shot in the last six months, if in the year 2022 you have not gotten a shot, you need to get one now,” Jha said. “You still can get a booster—an Omicron-specific booster—this fall and winter. Getting a shot now will not preclude you. But it will protect you for the rest of this summer into the fall. I think it’s really critically important.”