A Phase IV Double Blind Randomised Controlled Trial to Study Streptococcus Pneumoniae Serotype 3 Colonisation Following PCV15 Vaccination in Healthy Adults Aged 18 to 50 in the UK

What this Trial Is About

Researchers are evaluating the PCV15 vaccine to see if it can protect healthy adults aged 18 to 50 from carrying Streptococcus pneumoniae bacteria in their noses, which can lead to serious pneumonia in vulnerable people. This Phase IV double-blind study compares PCV15 with a placebo by exposing participants to a controlled amount of pneumococcus bacteria after vaccination to assess how well the vaccine prevents colonization. Participants will be randomly assigned to receive either one dose of PCV15 or a saline placebo injection. One month after vaccination, all participants will have a small amount of pneumococcus bacteria introduced into their noses. They will be closely monitored in the clinic for 28 days to assess bacterial colonization and immune responses, then take a 5-day course of antibiotics to clear the bacteria. A small group will undergo nasal biopsies to study immune reactions but will not receive the bacteria challenge. Throughout the study, participants will attend scheduled visits for lab tests, immune response assessments, and monitoring of bacterial presence on days 2, 7, 14, and 28 after bacterial exposure. Safety is carefully managed with regular check-ups, and participants who meet criteria will receive antibiotic treatment after the challenge. The entire study lasts about two months, including vaccination, bacterial challenge, follow-up, and antibiotic treatment.

Carriage to Assess Protection of New Pneumococcal Vaccines - PCV15