Hezhou

Researchers are evaluating a 20-valent pneumococcal conjugate vaccine 20vPnC in healthy infants to see if it is safe and helps the body make antibodies against 20 types of pneumococcal bacteria. This study compares the 20vPnC vaccine to an approved 13-valent pneumococcal conjugate vaccine 13vPnC in infants aged 42 to 98 days at the time of consent. The goal is to assess safety and immune response in this population. Infants will receive either the 20vPnC or 13vPnC vaccine in four doses three doses given approximately at 2, 4, and 6 months of age, and a fourth dose between 12 and 15 months of age. All doses for each infant will be the same vaccine. The study uses a randomized design and involves two groups receiving one of the vaccines. Participants will be monitored for reactions and adverse events from the day of each vaccination through specified follow-up periods. Blood samples will be taken to measure antibody levels at multiple time points, including one month after the third and fourth doses. The total participation time is about 16 to 19 months, with some infants invited to stay longer for additional monitoring. Safety and immune response data will be collected throughout the study duration.