A medical worker wearing a personal protective equipment PPE tends to a patient infected with the Covid-19 at the intensive care unit of the Mariinsky Hospital in Saint Petersburg on July 7, 2021. - Russia on July 4, 2021 counted more than 25,000 new daily infections after a week of record death tolls as the highly contagious Delta variant propels a global resurgence of the pandemic. The coronavirus has killed nearly four million people worldwide, forcing numerous nations to reimpose restrictions well over a year after the outbreak of the pandemic. (Photo by Olga MALTSEVA / AFP)