Kyla Drumm, 5, waits after receiving the Pfizer-BioNTech coronavirus disease (COVID-19) vaccine in Skippack, Pennsylvania, U.S., November 3, 2021. (Photo by Hannah Beier/Reuters)

A medical staff member rests next to a patient infected with Covid-19 in the intensive care unit of Lozenets Hospitalin Sofia on November 9, 2021. Bulgaria is among the countries with the highest number of deaths compared to its population. (Photo by Nikolay Doychinov/AFP Photo)

Los Angeles Chargers wide receiver Keenan Allen runs onto the field before an NFL football game against the Pittsburgh Steelers, Sunday, November 21, 2021, in Inglewood, Calif. (Photo by Ashley Landis/AP Photo)

Lava flows as volcano continues to erupt on the Canary island of La Palma, Spain, Monday, November 29, 2021. Several new volcanic vents opened in La Palma on Sunday, releasing new lava that flowed fast down a ridge and threatened to widen the impact on evacuated land, infrastructure and homes. (Photo by Emilio Morenatti/AP Photo)

Revellers enjoying the pubs and clubs in Leeds despite concerns over Omicron on December 10, 2021. Festive revellers have hit the pubs and clubs across the UK tonight as Plan B rules come into force and fears grow over the spread of Omicron. (Photo by Nb press ltd)

Steam comes out of the chimneys of the coal-fired power station Neurath near the Garzweiler open-cast coal mine in Luetzerath, Germany, Monday, October 25, 2021. The climate change conference COP26 will start next Sunday in Glasgow, Scotland. (Photo by Michael Probst/AP Photo)

Models are seen backstage ahead of the Hakan Akkaya x Cinderella Bridal Capsule Collection at Tersane Istanbul on November 30, 2021 in Istanbul, Turkey. (Photo by Ferda Demir/Getty Images for Hakan Akkaya)

Lava flows from an eruption of a volcano on the Reykjanes Peninsula in Iceland on March 28, 2021. A week on, big crowds of Sunday hikers flocked to the Fagradalsfjall area to see up close Iceland's latest volcano eruption, as the gentle lava flow allowed people to get close to he eruption some 40 km west of Iceland's capital Reykjavik. (Photo by Halldor Kolbeins/AFP Photo)