Researchers in the United States and in Sweden are working together to develop the world’s first vaccine against heart disease, one of the scientists involved said. “We have produced a simple form of vaccine that has worked well on test animals... Now we’re trying to develop it into a vaccine that has the quality and safety needed to use on humans,” Jan Nilsson, a professor at the Experimental Cardiovascular Research Unit of Lund University in southern Sweden, told AFP.The idea for the vaccine emerged just over a decade ago when Nilsson and US researcher Prediman K. Shah at the School of Medicine at the University of California, Los Angeles (UCLA) were studying low-density lipoproteins (LDLs), which cause most heart attacks and strokes.