As the world grapples with the Delta variant, will existing vaccines protect you? Eric Ding, senior fellow at the Federation of American Scientists, told CGTN anchor Wang Guan that the Delta variant will really be the next challenge and, even if you're vaccinated, it's not a bulletproof vest against being sick or transmitting the virus. Only with all measures including vaccines, masks, testing and border quarantine, together, can we contain the Delta variant.