From the Guidelines
PPSV (Pneumococcal Polysaccharide Vaccine) has limited effectiveness in preventing pneumococcal carriage and providing mucosal immunity, and therefore, pneumococcal conjugate vaccines are preferred for comprehensive protection, especially in children and for population-level protection through herd immunity. The evidence from the most recent study 1 suggests that the Advisory Committee on Immunization Practices (ACIP) has updated its recommendations for the use of PPSV23 and PCV13 among adults aged ≥65 years, emphasizing the importance of shared clinical decision-making for PCV13 use.
Key Points
- PPSV23 primarily induces a systemic antibody response without significant mucosal protection or reduction in nasopharyngeal carriage of Streptococcus pneumoniae 1.
- Polysaccharide vaccines stimulate B-cells directly without T-cell help, resulting in antibody production without establishing immune memory or significant mucosal IgA responses.
- Conjugate vaccines, such as PCV13, have been more successful in reducing overall pneumococcal disease burden through both direct protection and reduced transmission 1.
- The ACIP recommends routine use of PPSV23 for all adults aged ≥65 years, but PCV13 use should be based on shared clinical decision-making for adults aged ≥65 years who do not have an immunocompromising condition, cerebrospinal fluid (CSF) leak, or cochlear implant, and who have not previously received PCV13 1.
Implications for Practice
- Healthcare providers should consider the limited effectiveness of PPSV23 in preventing pneumococcal carriage and providing mucosal immunity when making vaccination recommendations.
- Pneumococcal conjugate vaccines, such as PCV13, should be preferred for comprehensive protection, especially in children and for population-level protection through herd immunity.
- Shared clinical decision-making is essential for determining the use of PCV13 among adults aged ≥65 years, taking into account individual risk factors and medical conditions 1.
From the Research
PPSV Polysaccharide Vaccine's Role in Carriage and Mucosal Immunity
- The PPSV polysaccharide vaccine plays a significant role in preventing pneumococcal disease in adults, including pneumonia and invasive disease 2.
- Vaccination with PPSV23 induces a humoral immune response, but its efficacy in preventing pneumonia is still debated 2.
- The conjugate vaccine, PCV13, stimulates good antibody responses, mucosal immunity, and suppresses colonization, offering benefits over the polysaccharide vaccine due to its T-cell-dependent response 2.
- Studies have shown that PPSV23 is effective against vaccine-type invasive pneumococcal disease and vaccine-type pneumococcal pneumonia, but its protection may be lower in adults aged ≥75 years or those with certain underlying conditions 3.
- The combination of PCV13 and PPSV23 may be superior to PPSV23 alone in reducing the incidence or severity of pneumonia in older adults, with improved immune response and adequate safety profiles 4.
- Pneumococcal vaccination strategies aim to stimulate effective antipneumococcal antibody and mucosal immunity response, with recent recommendations outlining the use of PPV23 and PCV13 based on age and risk factors 5.
- Systematic reviews have updated the evidence base for vaccine efficacy and effectiveness, indicating protective vaccine effectiveness for both PCV13 and PPV23 against vaccine-type pneumonia, with some studies suggesting that PPV23's effectiveness decreases over time 6.