In this April 14, 2014 file photo, Hamamatou Harouna, 10, who lost the use of her legs to polio, crawls to the restroom on the grounds of the Catholic Church where she and hundreds of others found refuge after fleeing violence in her village, in Carnot, Central African Republic. Health authorities on Tuesday, August 25, 2020 are expected to declare the African continent free of the wild poliovirus after decades of effort, though cases of vaccine-derived polio are still sparking outbreaks of the paralyzing disease in more than a dozen countries. (Photo by Jerome Delay/AP Photo/File)

Medical staff in Belgrade, Serbia on February 5, 2021. Vaccination of employees in the city's social protection institutions has begun at the Belgrade Fair, who have expressed interest in receiving the Russian Sputnik V vaccine, and according to the city secretary for social protection Natasa Stanisavljevic, about 150 employees in those institutions will receive the vaccine today and tomorrow. (Photo by Zoran Zestic/Tanjug)

A woman holds her dogs during a snow flurry as temperatures dropped below freezing during the third coronavirus lockdown in London, Tuesday, February 9, 2021. (Photo by Kirsty Wigglesworth/AP Photo)

Norway’s Daniel Andre Tande falls to the ground during the FIS Ski Jumping World Cup Flying Hill Individual competition in Planica on March 25, 2021. (Photo by Jure Makovec/AFP Photo)

A face mask is placed on one of the 'Three business men who brought lunch' statues on Swanston street on March 29, 2020 in Melbourne, Australia. All international arrivals into Australia from midnight on Saturday will be placed into mandatory quarantine in hotels for 14 days as the Federal Government increases restrictions to stop the spread of COVID-19. (Photo by Asanka Ratnayake/Getty Images)

Napoli fans celebrate after winning the Coppa Italia final against Juventus FC, in central Naples, Italy on June 17, 2020. Napoli won the Italian Cup with a 4-2 penalty shootout victory over Juventus following a 0-0 draw in a match played at the Rome Olympic Stadium. (Photo by Salvatore Laporta/IPA/Rex Features/Shutterstock)

A resident reacts as a health worker collects a swab sample to test for the Covid-19 coronavirus in Colombo on July 27, 2021. (Photo by Ishara S. Kodikara/AFP Photo)

A photograph made available on 30 September 2016 showing wind turbines at the site of the highest wind park in Europe at the Griessee, near the Nufenenpass in the Swiss south Alpes, Valais, Switzerland, on 23 September 2016. The four wind turbines of this wind park were developed by the company SwissWinds GmbH and are inaugurated on, 30 September 2016. (Photo by Olivier Maire/EPA)