Law enforcement and first responders gather outside Robb Elementary School following Tuesday's shooting in Uvalde, Texas. Their response has since come under wide scrutiny. Dario Lopez-Mills/AP hide caption

People arrive at a COVID-19 testing station in Houston, Texas, on Jan. 7. Texans were rushing to get tested as the state experienced an unprecedented spike in infections from the omicron variant. Francois Picard/AFP via Getty Images hide caption

Pfizer-BioNTech's COVID-19 vaccine for young children is a lower-dose formulation of the companies' adult vaccine. It was found to be safe and nearly 91% effective at preventing COVID-19. Paul Hennessy/SOPA Images/LightRocket via Getty hide caption

Ari Blank got a comforting hand-squeeze from his mom in May as he was vaccinated against COVID-19 in Bloomfield Hills, Mich. This week, the Food and Drug Administration authorized the use of Pfizer's vaccine in even younger kids — ages 5 to 11. Jeff Kowalsky/AFP via Getty Images hide caption

FDA may soon authorize the Pfizer COVID-19 vaccine for kids ages 5 to 11. Teens, like the 17-year-old pictured, are already eligible for the vaccine. Patrick T. Fallon/AFP via Getty Images hide caption

A pupil wearing a face mask reads instructions for a coronavirus rapid test kit at the start of a lesson at an elementary school in Berlin on August 9, 2021. Tobias Schwarz/AFP via Getty Images hide caption

A health care worker fills a syringe with the Pfizer-BioNTech COVID-19 vaccine at the American Museum of Natural History in New York City this year. Mary Altaffer/AP hide caption

A COVID-19 vaccine dose is prepared at a pharmacy in Baton Rouge, La., on Aug. 17. About 14 million people received their first dose of a COVID-19 vaccine in August. Mario Tama/Getty Images hide caption

A nurse fills a syringe with Johnson & Johnson's COVID-19 vaccine at a clinic in Pasadena, Calif., on Thursday. Robyn Beck/AFP via Getty Images hide caption

The CDC recommended that people with weakened immune systems get a third shot of either the Pfizer-BioNTech or Moderna vaccine. The move follows the FDA's authorization of such use a day earlier. Patrick T. Fallon/AFP via Getty Images hide caption

A teenager enters a pop-up COVID-19 vaccine site this month in the Jackson Heights neighborhood of Queens in New York City. Scott Heins/Getty Images hide caption

The CDC has softened its guidance for how to operate summer camps for kids this year. Children 12 and older can get the COVID-19 vaccine. Here, a health care worker administers a vaccine dose to a teenager in Miami. Eva Marie Uzcategui/Bloomberg via Getty Images hide caption

In Nashville, Tenn., a sign reminds visitors to wear masks at Belmont University, which is preparing to host Thursday's presidential debate. Federal health officials say a new study highlights the need for masks. Patrick Semansky/AP hide caption

The U.S. Food and Drug Administration headquarters in White Oak, Md. The agency this week has removed a top communications official in the wake of misleading claims it made about a treatment for COVID-19. Stefani Reynolds/Bloomberg via Getty Images hide caption

A lab technician dips a sample into an Abbott Laboratories ID Now testing machine at the Detroit Health Center on April 10. Carlos Osorio/AP hide caption

President Trump has previously suggested that a combination of hydroxychloroquine and azithromycin may help in the fight against the virus — but the Food and Drug Administration has strongly warned against taking hydroxychloroquine without medical monitoring. Mandel Ngan/AFP via Getty Images hide caption

A motorist gets a drive-through coronavirus test Thursday in Daly City, Calif. The U.S. has surpassed China to have the world's largest number of coronavirus cases. Justin Sullivan/Getty Images hide caption

President Trump turns away from Dr. Deborah Birx, White House coronavirus response coordinator, as she says she had a low-grade fever over the weekend and was tested for coronavirus. Alex Brandon/AP hide caption