Safety and Immunogenicity of a <i>Klebsiella pneumoniae</i> Tetravalent Bioconjugate Vaccine (Kleb4V) Administered to Healthy Adults: A First-in-Human Phase I/II Randomized and Controlled Study
Bibliographic record
Abstract
BACKGROUND: Safe and effective vaccines are urgently needed to prevent Klebsiella pneumoniae infections. We assessed safety and immunogenicity of a tetravalent bioconjugate vaccine Kleb4V, containing O antigen-polysaccharides of K. pneumoniae serotypes (O1v1, O2a, O2afg and O3b). METHODS: In this observer-blind, randomized, placebo-controlled, phase I/II trial (ClinicalTrials.gov NCT04959344), 166 healthy adults (16 aged 18-40 and 150 aged 55-70 years) were enrolled and randomized to receive 2 intramuscular injections of Kleb4V (16 or 64 μg of total O antigen with or without adjuvant AS03) or placebo on days 1 and 57. While the primary outcome was safety, the secondary outcomes included vaccine antigen immunogenicity. RESULTS: Kleb4V was well tolerated, with most solicited and unsolicited AEs of mild to moderate intensity. Kleb4V was immunogenic for all four vaccine-serotypes at both doses. O1v1, O2a and O2afg specific IgG increased after the 1st vaccination and IgG persisted at six months after the second vaccination. For three of the four vaccine-serotypes, the AS03-adjuvanted formulations showed a superior immune response. O3b responses were reduced compared to the other vaccine antigens. CONCLUSIONS: Kleb4V is the first K. pneumoniae conjugate vaccine candidate to reach clinical assessment. The Kleb4V bioconjugate was immunogenic and well tolerated in the target population of adults aged 55-70 years for the vaccine-serotypes.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.003 | 0.002 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.002 | 0.002 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.002 | 0.002 |
| Insufficient payload (model declined to judge) | 0.003 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".