Streptococcal Infections

This clinical study will enroll 100 participants from the 2-month-old (minimum 6 weeks) group who previously participated in the Phase III clinical trial of the 13-valent pneumococcal polysaccharide conjugate vaccine (CRM197, TT vector) (Protocol No.: CS-CTP-PCV), with 50 participants in each of the treatment and control groups, and who have completed blood sample collection for the 1-year and 2-year immunogenicity studies. All participants will have 3.0-3.5 mL of venous blood collected for the immunogenicity study.

This is a Phase 3 randomized, observation-blinded, active-controlled, parallel-group clinical trial designed to evaluate the immunogenicity, safety, and functional antibody response of the experimental vaccine versus the control vaccine in healthy Thailand infants vaccinated at a 2+1 schedule (2 months, 4 months and 12-15 months). The trial will enroll approximately 600 healthy infants aged 2 months (at least 6 weeks) who will be randomly assigned in a 1:1 ratio to receive either the experimental or control vaccine, with 100 in each group (200 in total) randomized to subgroups and subject to additional immunogenicity assessments. All participants will be evaluated for solicited adverse events for 7 days and unsolicited adverse events for 30 days post each vaccination. Immunogenicity evaluation will be performed in all participants at baseline and post the booster dose, while the sub-cohort participants will be evaluated for post primary series immunogenicity additionally.

Streptococcal anginosus infections (S. constellatus, S. anginosus, and S. intermedius) are characterized by their severity, linked to high mortality and frequent infectious complications. Several studies in the literature highlight this severity, with mortality rates estimated at around 15%. The aim of this research is to identify the factors associated with mortality in Streptococcal anginosus bacteremia.

The purpose of this study is to assess the safety of 3 doses of 2 new Strep A vaccine formulations, one with an Alum adjuvant, and the other with AS37 adjuvant. The Strep A vaccine will be tested for the first time in humans, in healthy young adults 18 to 25 years of age. The study will also assess if the vaccines have any immediate reactions and if they induce an immune response. A low, medium, and high dose of each formulation of the vaccine will be assessed in sequence.