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)

A Humboldt penguin swims in a pool during the annual stock take at ZSL London Zoo in London, Thursday, January 2, 2020. Caring for more than 500 different species, ZSL London Zoo's keepers face the challenging task of tallying up every animal large and small, every mammal, bird, reptile, fish and invertebrate at the Zoo. (Photo by Frank Augstein/AP Photo)

A model composes herself during the Ukrainian Fashion Week 2020-2021 at the Mystetskyi Arsenal National Art and Culture Museum Complex on February 4, 2020. (Photo by Irynka Hromotska/Radio Free Europe/Radio Liberty)

Journalists watch the take off of a German Eurofighter jet at the airbase in Noervenich, Germany, Thursday, August 20, 2020. Pilots from Israel and Germany will fly together the next two weeks during the first joint military Air Force exercises between the two nations in Germany. (Photo by Martin Meissner/AP Photo)

This photograph, taken on September 28, 2019, shows an Erythrina Abyssinica planted in a pasture on Ferme Espoir, owned by former President Joseph Kabila, in Masisi territory, northeast of the Democratic Republic of Congo. (Photo by Alexis Huguet/AFP Photo)

A robot, developed by start-up firm Asimov Robotics, holds a tray with face masks and sanitizer after the two robots were launched to spread awareness about the coronavirus, in Kochi, India, March 17, 2020. (Photo by Sivaram V/Reuters)

France's Alice Finot celebrates next to the mascot winning silver in the Women's 3000m final at the 2021 European Athletics Indoor Championships in Torun on March 5, 2021. (Photo by Aleksandra Szmigiel/Reuters)

In this Tuesday January 21, 2014, file photo, slaughtered chickens are displayed for sale at a wholesale poultry market in Shanghai. The Chinese government on Tuesday, June 1, 2021, says a 41-year-old man has contracted what might be the w0orld’s first human case of the H10N3 strain of bird flu, but the risk of large-scale spread is low. (Photo by AP Photo/File)