11. Evaluation of Lassa virus vaccine immunogenicity in the CBA / J-ML29 mouse model is ongoing. 12. In 1969 a live attenuated virus vaccine was licensed. 13. His field of research for several years was finding a live-virus vaccine against yellow fever. 14. In contrast, inactivated virus vaccines contain no living virus, and cannot cause a live infection. 15. But the method will still produce a live-virus vaccine and no one knows the potential risks. 16. A record epidemic terrified parents in 1953 even as Salk's killed-virus vaccine went through field trials. 17. But many scientists doubt that a killed-virus vaccine is the best way to achieve those goals. 18. The smallpox vaccine is a live-virus vaccine made from a virus similar to smallpox called vaccinia. 19. In 1959, Albert Sabin introduced his live-virus vaccine . 20. Dr . Albert Sabin's live-virus vaccine _ swallowed on a sugar cube _ was approved in 1961.
