A leaked Pentagon memo warns of “the real possibility of a resurgence” of the coronavirus and says that an effective vaccine will not be ready until “at least the summer of 2021,” contradicting Defense Secretary Mark Esper’s vow to deliver a vaccine “at scale” by the end of the year, Task and Purpose reports. “We have a long path ahead, with the real possibility of a resurgence of COVID-19,” the memo reads. The memo reportedly outlines a plan for the U.S. military to resume training and reposition forces, as well as supplies, to equip the country in the fight against the coronavirus. It was written by Kenneth Rapuano, assistant secretary of defense for homeland defense and global security, for Esper, however he didn’t sign it. It says the pandemic will “likely continue until there is wide-scale immunity, through immunization, and some immunity post-recovery from the virus.”

President Trump last week outlined a plan to deliver “hundreds of millions” of coronavirus vaccine doses by the end of this year. Dr. Anthony Fauci, the nation’s top infectious diseases expert, has said that developing a vaccine would take 12 to 18 months, in the best case scenario.