Cross reactivity within pneumococcal serogroups 6 and 15 following adult vaccination with pneumococcal conjugate...

Pneumococcal conjugate vaccines (PCVs) are designed to induce serotype-specific antibodies; however, antibodies raised against pneumococcal polysaccharides in the vaccine can also cross-react to other serotypes based on structural similarities. Cross-reactivity has been demonstrated for some licensed PCVs and is a worthy consideration to broaden protection against pneumococcal disease. This secondary analysis examined cross-reactive immune responses within serogroups 6 and 15 following vaccination with V116, an adult-specific PCV.

Antibody levels were assessed across five phase 3 clinical studies at baseline and 30 days following vaccination.

V116 elicits functional antibodies to vaccine serotypes 6A and 15C that result in cross-reactive antibodies to serotypes 6C and 15B, respectively, as assessed by opsonophagocytic activity responses from pre- to post-vaccination and IgG geometric mean concentrations.

V116-induced antibodies demonstrate cross-reactivity to serotypes 6C and 15B, suggesting protective immune responses may be raised against these non-vaccine serotypes.