CHAI begins work to lower costs and increase access to vaccines. Alongside the Bill & Melinda Gates Foundation, CHAI negotiates a landmark agreement to lower the price of the GSK rotavirus vaccine by 67 percent and the Biological E. Limited pentavalent vaccine by 50 percent, saving the global community over US$800 million and US$150 million respectively. The pentavalent vaccine averted an estimated 2.6 million deaths from 2011-2015.