This announcement was made after President Biden stated that he intends to provide directives to all the states and territories to make all adults over the age of 18 eligible for the experimental COVID-19 vaccines by May 1, 2021. 
Acting HHS Secretary Norris Cochran said:
As President Biden said last night, the key to getting us back to our lives is increasing vaccinations, and in order to do that, we need more vaccinators. … As vaccine supply ramps up, we want to be sure communities have the help they need to get shots into arms for anyone in the U.S. who wants to be vaccinated against COVID-19. 
Expanding List of Professionals Qualified to Administer COVID-19 Vaccines Under the PREP Act
The expanded COVID-19 vaccine administration workforce includes the following health professionals, who are currently or previously active within the last five years (retired or non-practicing health providers): dentists, emergency medical technicians (EMT), midwives, nurses, optometrists, paramedics, pharmacists, pharmacy interns, pharmacy technicians, physicians, physician assistant, podiatrist, respiratory therapists and veterinarians.