Comment on Chandler et al. 23-Valent Pneumococcal Polysaccharide Vaccination Does Not Prevent Community-Acquired Pneumonia Hospitalizations Due to Vaccine-Type Streptococcus pneumoniae. Microorganisms 2022, 10, 560

Abstract

The 23-valent pneumococcal polysaccharide vaccine (PPSV23) targets 23 common serotypes and is recommended for use in adults in various countries to protect against pneumococcal infection. Test-negative design (TND) studies aim to include cases and controls from the same healthcare facilities; however, design choices or limitations associated with conducting real-world research can affect the study results. Here, we highlight how some methodological limitations may have affected results and conclusions of a published study described by Chandler et al.