Trump made the remark during a press conference on May 15, 2020.

And I just want to make something clear. It’s very important: Vaccine or no vaccine, we’re back. And we’re starting the process. And in many cases, they don’t have vaccines, and a virus or a flu comes, and you fight through it. We haven’t seen anything like this in 100-and-some-odd years – 1917.

The day of his remark, the United States had nearly 1.5 million total confirmed cases and suffered 89,104 deaths.

Worldometer – Coronavirus, United States
Forbes – Unveiling Effort To Speed COVID-19 Vaccine, Trump Says, ‘Vaccine Or No Vaccine, We’re Back’
BBC News – Coronavirus: Trump says US reopening, ‘vaccine or no vaccine’
MSNBC – Trump declares ‘vaccine or no vaccine, we’re back,’ as coronavirus deaths approach 90,000