ThSABSe long-term immunogenicity of the 13-valent pneumococcal conjugate vaccine (PCV13), followed by the 23-valent pneumococcal polysaccharide vaccine (PPSV23) remains unclear among immunocompromised patients (ICPs). This three-year follow-up of a previously reported prospective cohort study included people living with HIV (PLWH), patients on immunosuppressive therapy, and immunocompetent controls who received PCV13 followed by PPSV23 two months later. IgG levels for all 24 vaccine serotypes were measured three years after PCV13 (M36). The primary outcome was the seroprotection rate (SPR) at M36, defined as IgG concentrations ≥1.3 μg/mL for 17/24 vaccine serotypes. To assess immunological memory, we measured rapid recall responses seven days after a PCV20 booster vaccination among initial responders two months after the priming schedule (M4) who had sero-reverted at M36. Between M4 to M36, SPRs dropped from 44% (22/50) to 9% (5/55) in PLWH, from 55% (59/108) to 17% (22/131) in patients on immunosuppressive therapy and from 82% (14/17) to 42% (8/19) in controls. Rapid recall responses were observed in 40% (4/10) of PLWH, 14% (2/14) of patients on immunosuppressive monotherapy, 22% (2/9) of patients on combination therapy, and 67% (2/3) of controls. Antibody levels increased significantly for 7/13 PCV20/PCV13-shared serotypes, but for none (0/7) of the PCV20/PPSV23-shared serotypes. Only a minority of PLWH and patients on immunosuppressive therapy and under half of controls remained seroprotected three years after vaccination. As rapid recall responses were limited to PCV serotypes, future research in ICPs should focus on expanded priming schedule with higher-valent PCVs such as PCV20.
Schnyder et al. (Wed,) studied this question.