Which vaccine is listed as preventing bacterial pneumonia?

• A. Pneumococcal Conjugate Vaccines (PCV15 or PCV20)
• B. PPSV23
• C. Influenza vaccine
• D. Meningococcal vaccine

Answer: (A)

Streptococcus pneumoniae is a leading cause of bacterial pneumonia, so vaccines that target pneumococcus directly reduce this type of pneumonia. Pneumococcal conjugate vaccines (PCV15 or PCV20) are designed to protect against multiple pneumococcal serotypes by linking polysaccharides to a protein, which creates a stronger, longer-lasting immune response. This approach not only lowers invasive pneumococcal disease but also reduces pneumococcal pneumonia by decreasing carriage and infection with those serotypes.

In contrast, the influenza vaccine protects against influenza virus and can indirectly reduce secondary bacterial pneumonia but doesn’t prevent bacterial pneumonia itself. The meningococcal vaccine targets Neisseria meningitidis, not pneumococcus. While PPSV23 also covers many pneumococcal serotypes, its immune response is less robust for pneumonia prevention in some groups compared with conjugate vaccines, which is why the pneumococcal conjugate vaccines are the ones listed as preventing bacterial pneumonia.