A Phase 2 Study Evaluating the Safety and Efficacy of Whole-Cell Pneumococcal Vaccine (wSp) in Reducing Nasopharyngeal Colonization by Streptococcus Pneumoniae in Young Children.

Summary

The goal of this clinical trial is to evaluate whether the wSp vaccine can prevent nasopharyngeal colonization by pneumococcal bacteria in healthy young children who have received routine PCV15 or PCV20 vaccination. The main questions it aims to answer are: Does wSp vaccine reduce pneumococcal colonization in the nose? Does wSp vaccine safely stimulate the immune system to produce antibodies and protective immune responses? Researchers will compare children receiving two injections of wSp vaccine to those receiving saline placebo to see if wSp vaccine reduces colonization and boosts immunity. Participants will: Receive two injections of either wSp or saline at approximately 7 and 9 months of age. Have blood samples taken at 6 and/or 12 months to measure immune responses. Have nasal swabs collected at several time points and during infections from 6-24 months. Be monitored for ear infections, respiratory illnesses, and other pneumococcal-related infections.

Eligibility

Age range

0–0 years

Sex

All

Healthy volunteers

Yes

Interventions

• Biological
  wSp vaccine

  wSp vaccine will be administered as intramuscular (IM) injections of 0.5 mL (thus 1 mg total protein). wSp vaccine is supplied as single-dose glass vials in saline (0.9% sodium chloride) at 2 mg protein/mL, with aluminum hydroxide at 1.2 mg elemental Al/mL. Dose 1 will be given preferably in the left thigh at approximately 7 months of age, and dose 2 will be given preferably in the right thigh at approximately 9 months of age.

• Biological
  Saline (0.9% NaCl)

  Saline will be administered as intramuscular (IM) injections of 0.5 mL. Dose 1 will be given preferably in the left thigh at approximately 7 months of age and dose 2 will be given preferably in the right thigh at approximately 9 months of age.

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