The current wave of COVID-19 cases driven by the Delta coronavirus variant has the potential to be the country"s last major wave of infection — but it"s far from over, and even endemic Covid will pose problems, a former Food and Drug Administration (FDA) chief said. "I think this Delta wave may be the last major wave of infection, assuming nothing unexpected happens, (such as getting) a variant that pierces the immunity offered by prior infection (and) by vaccination," former FDA Commissioner Dr. Scott Gottlieb told CNN Thursday. “You’re going to see the Delta variant course its way through different parts of the country now that said, this is probably the last major wave of infection to sweep the nation,” said Dr. Gottlieb. The US is still battling the Delta variant and will likely continue to into the winter. The variant is well known for how transmissible it’s been, which has further emphasizing the push for vaccines. “There is as possibility that he may be right, and I certainly hope so there’s still ample places where new variants can form and recombine,” said Infectious disease expert Dr. Aileen Marty from Florida International University. The latest data from the Centers for Disease Control and Prevention shows just over 75%t of adults in the country have received at least one dose, but Dr. Gottlieb said that needs to be in the 80-85% range to really see cases go down. “What keeps me up at night is the possibility of a recombinant of the Delta variant and something like the beta variant or the mu variant,” said Dr. Marty. For some confusion also lingers about vaccinations for those who have already had COVID-19 and have antibodies. Dr. Marty said those folks still need a vaccine as some antibodies made by the natural infection can do more harm than good. “They can actually cause disease, that’s why some people end up with long COVID symptoms, that’s part of the spectrum — the formation of antibodies that harm you because your body as trying to make antibodies to help you but didn’t know where to attack the virus,” said Dr. Marty. Though national daily cases are inching downward for over a week, the overall Delta-influenced wave isn"t done and cases still may spike — especially as colder weather approaches, and especially in regions like the Northeast that haven"t been as hard hit as other places, Dr. Gottlieb said. The pace of COVID-19 vaccinations is the slowest it"s been in two months, CDC data shows, worrying health professionals as flu season approaches. "I think we"re going to see infections start to pick up here (in the Northeast), as well, as kids go back to school, schools become sources of community transmission, and people start to go back to work and the weather gets cold," Gottlieb said. — CNN with input from agencies