The wave has already started, there are plenty antivaxxers out there who would rather die than take it. US uptake of the vaccine will be 70% max because of the nonbelievers and antiscience people that form the core of Trump's cadre. There's still plenty people left to kill and I bet we will hit at least 600,000 (aka another 50000) by the end of the year. There absolutely will be a 4th wave.