Assessment of functional antibacterial opsonophagocytic antibodies elicited by 13-valent pneumococcal conjugate vaccine administered concomitantly with trivalent influenza vaccine in a randomized clinical trial in adults aged ≥65 years

► PCV13 was coadministered with TIV or given separately 1 month after TIV. ► OPA responses were lower after coadministration compared to separate administration. ► Noninferiority criteria were met for most serotypes after vaccine coadministration. ► The proportion of OPA responders was similar across the two vaccine groups. ► The concomitant use of PCV13 and TIV should be guided by clinical circumstances.