GSKâsÂ candidateÂ Shingles VaccineÂ Containing Agenusâ QS-21Â StimulonÂ® DemonstratesÂ 90% EfficacyÂ against ShinglesÂ andÂ 89%Â EfficacyÂ againstÂ Post-Herpetic NeuralgiaÂ inÂ Adults agedÂ 70 Years and Older