Seven-year-old Mimi Meade winces from the sting as Dr. Richard Mulvaney inoculates her April 26, 1954 in McClean, Va., with the new Salk polio vaccine. Mrs. John Lucas, a registered nurse, holds Mimi's arm steady as she gets one of the first injections of the countrywide test. (Photo by Harvey Georges/AP Photo)

Cosplayers wearing face masks pose for a picture at the China Digital Entertainment Expo and Conference (ChinaJoy) in Shanghai, following the coronavirus disease (COVID-19) outbreak, China on July 31, 2020. (Photo by Aly Song/Reuters)

A man wearing a face mask amid the COVID-19 pandemic passes a mural of Venezuelan President Nicolas Maduro in Caracas, Venezuela, Wednesday, July 22, 2020. Analysts say that in recent months the pandemic has helped suck away the opposition’s scanty momentum and bolster Maduro’s already strong hand. (Photo by Ariana Cubillos/AP Photo)

General view of a clash after the match of the Egyptian Premier League between Pyramids FC and Zamalek at the 30 June Air Defense Stadium in Cairo, Egypt on April 23, 2019. (Photo by Amr Abdallah Dalsh/Reuters)

Over 30 Douglas C-47 Skytrains (Dakotas) making final preparations for flight formation practice before the 75th D-Day Anniversary flight to Normandy in Duxford, England on June 4, 2019. (Photo by UK Air Force Images)

Reality TV personality Kim Kardashian speaks alongside US President Donald Trump during a second chance hiring and criminal justice reform event in the East Room of the White House in Washington, DC, June 13, 2019. (Photo by Saul Loeb/AFP Photo)

A Pakistan fan poses for a photo during the Group Stage match of the ICC Cricket World Cup 2019 between Australia and Pakistan at The County Ground on June 12, 2019 in Taunton, England. (Photo by Alex Davidson/Getty Images)

A robin perches on a spade handle in a garden on a rainy day in Lixwm, north Wales. Researchers said this week that when European robins are subjected to human-produced noise, their behaviour changes. (Photo by DGDImages/Alamy Live News)