Open-label, randomised controlled, multicentre study evaluating higher valency pneumococcal vaccines (PCV15/PCV20) compared with PCV13 given in homologous schedules at 3 months and 12 months (‘1+1’ schedule) and 2 months, 4 months and 12 months (‘2+1’ schedule) in infants: protocol

Journal article

BACKGROUND: Most recent childhood invasive pneumococcal disease in the UK is caused by serotypes not included in the currently used pneumococcal conjugate vaccine (PCV13). There is potential for additional protection with newer PCVs that have wider serotype coverage but there are no data on these vaccines being given in the 1+1 schedule used in the UK. This study will determine whether the PCV13 serotype-specific antibody responses to PCV15 and PCV20 given at 3 and 12 months (1+1 schedule) are non-inferior to PCV13 serotype-specific antibody responses to PCV13 given in the same schedule. It will also determine whether PCV13 serotype-specific antibody responses to PCV20 given at 2, 4 and 12 months (2+1 schedule) are non-inferior to PCV13 serotype-specific antibody response to PCV13 given at 3 and 12 months (1+1 schedule). METHODS: This will be an open-label, randomised controlled multicentre study in 600 infants. Healthy infants will be enrolled at 8 weeks and randomised 1:1:1:1 to receive 2 doses (1+1) of either PCV15, PCV20 or PCV13 at 3 and 12 months of age or 3 doses (2+1) of PCV20 at 2, 4 and 12 months. Blood and nasal samples will be collected at specified intervals to assess serum and nasal IgG levels and carriage. Postprimary and postbooster IgG levels in the PCV15 and PCV20 arms will be compared against PCV13. ETHICS AND DISSEMINATION: Ethical approval for this study has been obtained from the South Central-Hampshire A Research Ethics Committee (REC ref 24/SC/0222). The results will be disseminated via publication in a peer-reviewed journal and presentations at international conferences. TRIAL REGISTRATION NUMBER: ISRCTN17673117.

Authors: Aslam, R; Akeju, O; Clutterbuck, E; Appleby, C; Murphy, D

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: BMJ Publishing Group
• Journal: BMJ Open
• Volume: 16
• Issue: 9
• Pages: e116062-e116062
• Publication date: 2026-09-22
• DOI: 10.1136/bmjopen-2025-116062
• EISSN: 2044-6055
• ISSN: 2044-6055
• Language: English
• Keywords: Pneumococcal disease; Antibody response; Antibody; Clinical trial; Serotype; Pneumococcal vaccine; Pneumococcal conjugate vaccine