Vaccine scientists have been chasing variants. Now, they’re seeking a universal coronavirus vaccine.

“We have been studying influenza viruses more than 70 years, and we are trying to make universal influenza vaccines, and we still haven’t been able to do it,” said Yoshihiro Kawaoka, who is working on a pan coronavirus vaccine at the University of Wisconsin at Madison. “But this is a different virus, and I think it’s worth trying. What I’m trying to say is that it may not be easy