Overview
- Pfizer reported mid-stage results in infants showing a stronger immune response than Prevnar 20, with antibody levels about 8.8 times higher after dose three and about 15 times higher after dose four.
- Following those data and talks with regulators, the company has begun a head-to-head late-stage trial in up to 2,400 infants using a four-dose schedule against Prevnar 20.
- The mid-stage study found the vaccine was well tolerated with no safety concerns, and the most common reactions were redness, swelling, and pain at the injection site.
- The 25-strain design includes serotype 3, a leading cause of severe pneumococcal illness in children, which can drive complicated pneumonia and invasive infections.
- Pfizer also plans a 35-strain adult candidate and expects to start clinical testing by the end of 2026.