Ofori-Anyinam O, et al. - In a study population comprising adults at high risk of complications of influenza and pneumococcal infection, the impacts of co-administration or separate administration of an inactivated quadrivalent influenza vaccine (IIV4) with a 23-valent pneumococcal polysaccharide vaccine (PPV23) were assessed. Findings demonstrated that co-administration of IIV4 and PPV23 did not attenuate antibody responses reflecting protection against influenza or pneumococcal disease. In addition, uptake may be improved via co-administration of PPV23 at the annual influenza vaccination visit. IIV4 immunogenicity remained unaltered by the presence of comorbidities, supporting its value in older adults with chronic medical conditions.