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 reacts as she receives the AstraZeneca/Oxford vaccine under the COVAX scheme against coronavirus disease (COVID-19) at the Kenyatta National Hospital in Nairobi, Kenya on March 5, 2021. (Photo by Monicah Mwangi/Reuters)

A Vietnamese woman collects dried incense sticks at a courtyard in Quang Phu Cau village on the outskirts of Hanoi on January 9, 2020 ahead of the upcoming Lunar New Year celebrations, referred to in Vietnam as Tet. (Photo by Manan Vatsyayana/AFP Photo)

Dogs wearing masks are seen at a main shopping area, in downtown Shanghai, China, as the country is hit by an outbreak of a new coronavirus, February 16, 2020. (Photo by Aly Song/Reuters)

An employee in protective gears sprays disinfectant at the main exhibition tank at the Sea World at Jaya Ancol Dream Park as it is closed for public in the wake of coronavirus outbreak in Jakarta, Indonesia, Saturday, March 14, 2020. Indonesia's capital city announced a lockdown of all tourist destinations and entertainment spots as well as the closing all of its public schools for the next 14 days amid the global outbreak. For most people, the new coronavirus causes only mild or moderate symptoms. For some it can cause more severe illness. (Photo by Dita Alangkara/AP Photo)

An Iraqi medic takes a nasal swab from a woman in Iraq's central shrine city of Najaf on April 20, 2020, during the nationwide lockdown to stem the spread of the novel coronavirus. (Photo by Haidar Hamdani/AFP Photo)

People walk along Beachy Head, close to Eastbourne on the south coast of England on April 12, 2020, as life in Britain continues over the Easter break, during the nationwide lockdown to combat the novel coronavirus pandemic. Britain's Prime Minister Boris Johnson was making “very good progress” on Saturday in his recovery in hospital from coronavirus, officials said, as the country's deaths toll from the disease approached the grim milestone of 10,000. (Photo by Ben Stansall/AFP Photo)

View of a group of ostriches, in the gardens of the Palacio do Alvorada, in Brasilia, Brazil, 02 June 2020. The ostrich is the largest and heaviest bird in the world. When the chicks hatch they are between 25 and 30 cm tall, weighing about 900 grams. (Photo by Joedson Alves/EPA/EFE/Rex Features/Shutterstock)