** Shares of vaccine maker Novavax NVAX.O rise 1.5% to $8.58 premarket
** Co appoints Robert Walker as executive vice president and head of research and development, effective immediately
** Walker, previously the firm's chief medical officer, replaces Ruxandra Draghia-Akli, who has left the company
** Co says Walker will oversee preclinical and clinical research as Novavax works to advance its vaccine pipeline
** Walker has more than 30 years of experience in drug and vaccine development, including roles at the U.S. Department of Health and Human Services, co says
** Shares fell ~16% in 2025
(Reporting by Sahil Pandey in Bengaluru)
((Sahil.Pandey@thomsonreuters.com))