(CNN)The new coronavirus is likely to keep spreading for at least another 18 months to two years—until 60% to 70% of the population has been infected, a team of longstanding pandemic experts predicted in a report released Thursday. They recommended that the US prepare for a worst-case scenario that includes a second big wave of coronavirus infections in the fall and winter. Even in a best-case scenario, people will continue to die from the virus, they predicted. “This thing’s not going to stop until it infects 60 to 70 percent of people,” Mike Osterholm, who directs the Center for Infectious Disease Research and Policy (CIDRAP) at the University of Minnesota, told CNN. “The idea that this is going to be done soon defies microbiology.” Osterholm has been writing about the risk of pandemics for 20 years and has advised several presidents. He wrote the report along with Harvard School of Public Health epidemiologist Marc Lipsitch, who is also a top expert on pandemics; Dr. Kristine Moore, a former Centers for Disease Control and Prevention epidemiologist who is now medical director for CIDRAP; and historian John Barry, who wrote the 2004 book “The Great Influenza” about the 1918 flu pandemic.