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Randomized Controlled Trial
. 2026 Mar 7:75:128236.
doi: 10.1016/j.vaccine.2026.128236. Epub 2026 Jan 22.

Safety and immunogenicity of a 25-valent pneumococcal conjugate vaccine in pneumococcal vaccine-naive healthy adults: Results from 2 randomised, controlled clinical trials

Joanne M Langley  1 , Manish Sadarangani  2 , Christian Ockenhouse  3 , Luis Barreto  4 , Lingyun Ye  5 , Yuxiao Tang  3 , Janis L Breeze  5 , Jodi Feser  3 , Nancy A Hosken  3 , Indah Andi-Lolo  6 , Sybil A Tasker  7 , Scott A Halperin  5 ; Canadian Immunization Research Network  5
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Free article
Randomized Controlled Trial

Safety and immunogenicity of a 25-valent pneumococcal conjugate vaccine in pneumococcal vaccine-naive healthy adults: Results from 2 randomised, controlled clinical trials

Joanne M Langley et al. Vaccine. .
Free article

Abstract

Background: Pneumococcus causes substantial morbidity and mortality worldwide in children under 5. IVT PCV-25 is a 25-valent pneumococcal conjugate vaccine (PCV25) designed to prevent invasive pneumococcal disease from the serotypes predominant in children, particularly in low and middle income countries (LMICs).

Methods: We completed 2 randomised, parallel-group, double-blind clinical trials in Canada to evaluate the safety and immunogenicity of a single IM dose of PCV25 in healthy adults who had no history of pneumococcal vaccination or microbiologically confirmed IPD. PCV20 (Prevnar 20) was the control. In CVIA 096, 30 participants per group were randomised to PCV25 at a dose similar to PCV 20 (2.2 μg for each serotype polysaccharide (except 4.4 μg for serotype 6B) with 125 μg aluminium as aluminium phosphate (2.2/125)) or PCV20. Potentially more immunogenic formulations with higher polysaccharide and/or aluminium phosphate dose were evaluated in CVIA105, where 40 participants were randomised to PCV25 (2.2/125), 60 to PCV25 (2.2/250), 80 to PCV25 (4.4/250), and 40 to PCV20.

Results: Most participants were female and white. All participants were included in the safety analyses. One participant in CVIA 096 and 6 participants in CVIA 105 were excluded from the immunogenicity analyses because of protocol deviations that might interfere with immune response. Solicited and unsolicited AE profiles were similar for PCV25 and PCV20. No Grade 4 events were reported. At the highest dose, PCV25 elicited IgG and OPA responses with GMFRs of ≥2 for all 25 serotypes and for serotype 6A except for OPA response to 35B.

Conclusions: Multiple formulations of IVT PCV-25, a vaccine designed to cover pneumococcal serotypes prevalent in LMICs, were well tolerated and immunogenic in healthy adults. As adult immunogenicity is not fully predictive for infants, further development will evaluate safety and immunogenicity in the target infant population.

Clinicaltrials: govNCT05540028,NCT06077656.

Keywords: Clinical trial; Dose-ranging; Immunogenicity; Pneumococcal conjugate vaccine; Safety.

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Conflict of interest statement

Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Joanne M. Langley, Manish Sadarangani, Christian Ockenhouse, Luis Barreto, Lingyun Ye, Yuxiao Tang, Janis L. Breeze, Jodi Feser, Nancy A. Hosken, Indah Andi-Lolo, Scott A. Halperin reports financial support, article publishing charges, and writing assistance were provided by Inventprise. Sybil Tasker reports article publishing charges, travel, and writing assistance were provided by Inventprise. Scott Halperin, reports a relationship with Merck & Co Inc. that includes: funding grants. Scott Halperin reports a relationship with Pfizer that includes: funding grants. Scott Halperin reports a relationship with GSK Vaccines that includes: consulting or advisory. Scott Halperin reports a relationship with Moderna Inc. that includes: consulting or advisory. Scott Halperin reports a relationship with AstraZeneca that includes: consulting or advisory. Scott Halperin reports a relationship with Seqirus Inc. that includes: consulting or advisory. Scott Halperin reports a relationship with Aramis that includes: consulting or advisory. Luis Barreto reports a relationship with CanSino Biologics Inc. that includes: consulting or advisory. Luis Barreto reports a relationship with Medicago Inc. that includes: consulting or advisory. Joanne M. Langley reports a relationship with Merck & Co Inc. that includes: funding grants. Joanne M Langley reports a relationship with GSK Vaccines that includes: consulting or advisory. Joanne M Langley reports a relationship with Vaxcyte Inc. that includes: consulting or advisory. Joanne M Langley reports a relationship with Meningitis Foundation of Canada that includes: consulting or advisory. Manish Sadarangani reports a relationship with Merck & Co Inc. that includes: funding grants. Manish Sadarangani reports a relationship with Moderna Inc. that includes: funding grants. Manish Sadarangani reports a relationship with Pfizer that includes: funding grants. Manish Sadarangani reports a relationship with GlaxoSmithKline that includes: funding grants. Manish Sadarangani reports a relationship with Sanofi Pasteur Inc. that includes: funding grants. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

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