Washington, United States — ( AFP)Johnson and Johnson’s single-shot Covid-19 vaccine is effective against the highly contagious Delta variant, with an immune response lasting at least eight months, the company said Thursday. The antibodies and immune system cells in the blood of eight people vaccinated with the J&J jab effectively neutralized the Delta strain, which was first identified in India, researchers found. A second study with 20 vaccinated patients at Boston’s Beth Israel Medical Center […]