The government’s top infectious disease expert told a House committee on Tuesday he believes “it will be when and not if” there will be a COVID-19 vaccine and that he remains “cautiously optimistic” that some will be ready at the end of the year.

Next month, the University of Illinois at Chicago will begin testing a vaccine to see if it will prevent people from getting the novel coronavirus or experiencing severe illness from it if they do get it.

Only about half of Americans say they would get a COVID-19 vaccine if the scientists working furiously to create one succeed, a number that’s surprisingly low considering the effort going into the global race for a vaccine.

Whistleblower Dr. Rick Bright warned on Thursday that the U.S. lacks a plan to produce and fairly distribute a coronavirus vaccine when it becomes available.