The butter-like material only melts when it hits the respiratory tract, leaving the virus free to infect cells - a process scientists say is like an M&M melting in the mouth.

这种油状物质在进入呼吸道后才会融化，病毒被释放后即会感染细胞。科学家称这一过程如同M&M巧克力豆在嘴里融化。