The Johnson & Johnson COVID-19 Vaccine is a single-dose vaccine developed to protect against the COVID-19 virus. It uses a viral vector technology, which means it delivers a harmless piece of the virus's genetic material to stimulate an immune response without causing the disease. This vaccine has been authorized for emergency use by the U.S. Food and Drug Administration (FDA) and is effective in reducing the risk of severe illness, hospitalization, and death from COVID-19. It is particularly beneficial for individuals who may have difficulty returning for a second dose, as it requires only one shot.