Timeline of major events in influenza vaccine development. Timeline of major events in influenza vaccine development. Influenza pandemics and major H5N1 outbreaks are indicated in red, while major breakthroughs in influenza vaccine development are highlighted in blue. Superscript numbers indicate references. *, see the FDA website (http://www.fda.gov/); ∧, see the European Medicines Agency website (http://www.ema.europa.eu); #, see the CDC website (http://www.cdc.gov/vaccines/acip/index.html). Sook-San Wong, and Richard J. Webby Clin. Microbiol. Rev. 2013; doi:10.1128/CMR.00097-12