Even as governments are loosening restrictions put in place to contain the spread of the coronavirus, a new report warns they should be planning for the worst. That includes, USA Today reports, the possibility of "no vaccine availability or herd immunity." In fact, the study found, everyone should "be prepared for possible periodic resurgences of disease" over as long as two years. The University of Minnesota's Center for Infectious Disease Research and Policy produced the study, with the help of pandemic experts from Harvard and Tulane universities. They analyzed data from this outbreak and eight major influenza pandemics, starting in the 1700s, per CBS. Seven of the influenza pandemics had a second significant peak about six months after the first, and some of them had "smaller waves of cases over the course of 2 years."
This pandemic probably will last 18 to 24 months, the authors said, partly because of the time it takes for 70% of the population to develop immunity—the level they say will be needed to achieve herd immunity. The report detailed three possible scenarios: a major resurgence of infections, worse than the current crisis, before the end of the year; a resurgence, followed by a series of smaller waves into next year; and a "slow burn," with no pattern evident in the transmission of the coronavirus. The third possibility hasn't occurred in the other pandemics. But "the virus caught the global community off guard, and its future course is still highly unpredictable," the report says. So it's not clear yet how the outbreak will be brought under control, the researchers said. (Read more coronavirus stories.)