Fig. 2From: Immunogenicity and safety of a tetanus-diphtheria vaccine and a 13-valent pneumococcal conjugate vaccine after concomitant vaccination in ≥ 50-year-old adultsComparison of geometric mean titers at one month post-vaccination. Enzyme-linked immunosorbent assay: tetanus-diphtheria (Td) vaccine + 13-valent pneumococcal conjugate vaccine (Group 1) versus Td vaccine alone (Group 3). Opsonophagocytic activity (OPA): Td vaccine + 13-valent pneumococcal conjugate vaccine (Group 1) versus 13-valent pneumococcal conjugate vaccine alone (Group 2)Back to article page