"Medical experts worldwide agree that the period spanning late 2020 and early 2021 will be remembered as one of the most consequential in the history of modern science. COVID-19, a devastating, contagious disease characterized by acute respiratory difficulties, raged across the globe. Multiple vaccines have now been designed to fight back against COVID-19. Most often injected through a shot in the arm, a vaccine is a human-made substance that induces the body to become resistant, or even immune, to a given disease." -- Provided by publisher.