First lady Jill Biden, right, and Jackson-Hinds Comprehensive Health Center CEO Jasmin Chapman speak to recently vaccinated patients during a visit to a COVID-19 vaccination site at Jackson State University in Jackson, Miss., Tuesday, June 22, 2021, as part of Biden administration's nationwide tour to reach Americans who haven't been vaccinated and to promote vaccine education. (AP Photo/Rogelio V. Solis)

First Lady Jill Biden speaks of the importance of being vaccinated during her visit to a COVID-19 vaccination site at Jackson State University in Jackson, Miss., Tuesday, June 22, 2021, as part of the Biden administration's nationwide tour to reach Americans who haven't been vaccinated and to promote vaccine education. (AP Photo/Rogelio V. Solis)

First lady Jill Biden, right, and Jackson-Hinds Comprehensive Health Center CEO Jasmin Chapman speak to recently vaccinated patients during a visit to a COVID-19 vaccination site at Jackson State University in Jackson, Miss., Tuesday, June 22, 2021, as part of Biden administration's nationwide tour to reach Americans who haven't been vaccinated and to promote vaccine education. (AP Photo/Rogelio V. Solis)

First lady Jill Biden waves to assembled local media as she makes her way past COVID education posters during a visit to vaccination site at Jackson State University in Jackson, Miss., Tuesday, June 22, 2021, as part of the Biden administration's nationwide tour to reach Americans who haven't been vaccinated and to promote vaccine education. (AP Photo/Rogelio V. Solis)

First lady Jill Biden waves to assembled local media as she makes her way past COVID education posters during a visit to vaccination site at Jackson State University in Jackson, Miss., Tuesday, June 22, 2021, as part of the Biden administration's nationwide tour to reach Americans who haven't been vaccinated and to promote vaccine education. (AP Photo/Rogelio V. Solis)

First Lady Jill Biden speaks about how vaccinated people have the freedom to again interact without fear of getting sick, during her visit to a COVID-19 vaccination site at Jackson State University in Jackson, Miss., Tuesday, June 22, 2021, as part of the Biden administration's nationwide tour to reach Americans who haven't been vaccinated and to promote vaccine education. (AP Photo/Rogelio V. Solis)

First lady Jill Biden boards an aircraft at Jackson-Medgar Wiley Evers International Airport, in Pearl, Miss., Tuesday, June 22, 2021. (Tom Brenner/Pool via AP)

Prepped vaccine filled syringes are at ready for use at a COVID-19 vaccination site at Jackson State University in Jackson, Miss., prior to a visit by First Lady Jill Biden, Tuesday, June 22, 2021, as part of the Biden administration's nationwide tour to reach Americans who haven't been vaccinated and to promote vaccine education. (AP Photo/Rogelio V. Solis)