The second,or booster, vaccine was developed by VaxGen.

VOA: special.2009.09.30

"Booster ignition and lift off for space shuttle Discovery, taking the space station to full power for full science,"

VOA: standard.2009.03.15

Kennedy was a mentor during his early days in the United States Senate, and was an early and avid booster of his presidential campaign.

VOA: standard.2009.08.26