September 25, 2017 https://academic.oup.com/jpids/article-abstract/6/3/e69/3003229/Immunogenicity-of-a-Booster-Dose-of-Quadrivalent?redirectedFrom=fulltext Health Affairs: Corporate Investors Increased Common Ownership In Hospitals And The Postacute Care And Hospice Sectors Human Vaccines & Immunotherapeutics: Safety and immunogenicity of a quadrivalent influenza vaccine in adults 65 y of age and older