Javier is a Principal Scientist at MHRA South Mimms where he leads the Polio Laboratory Group. He completed his Ph.D. studies at the Universidad Autonoma, Madrid, Spain, successfully developing a novel technique to generate genetically modified synthetic influenza viruses used to develop prospective synthetic vaccines. Javier then spent four years as a postdoctoral scientist at the National Institute for Medical Research, Mill Hill, London UK, where he continued his work on influenza virus. He moved to the NIBSC, now MHRA, in 1998 where he is the Head of the WHO Polio Global Specialized Laboratory supporting the WHO Global Polio Eradication Initiative both on disease surveillance and vaccine control, standardization and development.