Immunogenicity and safety of a 13-valent pneumococcal conjugate vaccine in adults 70 years of age and older previously vaccinated with 23-valent pneumococcal polysaccharide vaccine

BACKGROUND

The currently recommended single dose of the 23-valent pneumococcal free polysaccharide vaccine (PPSV23) for adults 65 years of age and older does not provide extended protection into older age. This reflects a significant unmet medical need for alternative strategies to protect older adults against pneumococcal infection, which may be met by the 13-valent polysaccharide conjugate vaccine (PCV13).

METHODS

We performed a randomized, modified double-blind trial in 936 adults aged 70 years and older who had previously received PPSV23 at least 5 years before study entry and were now vaccinated with PCV13 or PPSV23. At 1 year after enrollment, all subjects received a follow-on dose of PCV13. Anti-pneumococcal opsonophagocytic activity (OPA) titers were measured before and at 1 month after each vaccination.

RESULTS

Following the enrollment vaccination, OPA titers were significantly greater in the PCV13 group compared to the PPSV23 group for 10 of the 12 serotypes common to both vaccines and to serotype 6A which is unique to PCV13. Responses were noninferior for the other 2 common serotypes. Responses to PCV13 given at 1 year were generally lower in the group that received PPSV23 at enrollment.

CONCLUSION

In adults aged 70 years and older previously vaccinated with PPSV23, PCV13 was significantly more immunogenic than PPSV23 for most of the common serotypes and for serotype 6A. The OPA responses after a follow-on dose of PCV13 one year later indicate that a prior dose of PPSV23, but not PCV13, diminishes the response to the subsequent administration of PCV13.

Influence of initial vaccination with 13-valent pneumococcal conjugate vaccine or 23-valent pneumococcal polysaccharide vaccine on anti-pneumococcal responses following subsequent pneumococcal vaccination in adults 50 years and older

BACKGROUND

Unlike free polysaccharide vaccines, pneumococcal polysaccharide conjugate vaccines (PCVs) induce a T cell-dependent immune response and have the potential to provide an extended duration of protection with repeated vaccinations.

METHODS

This was an extension of a previous study in pneumococcal vaccine-naïve adults aged 50-64 years in which adults 60-64 years of age were given 13-valent PCV (PCV13) or 23-valent pneumococcal polysaccharide vaccine (PPSV23) and adults aged 50-59 were given PCV13. In this follow up study conducted about 4 years later, the 60-64 year olds initially given PCV13 received PCV13 or PPSV23, and those initially given PPSV23 received another PPSV23. All adults aged 50-59 years were re-vaccinated with PCV13. Anti-pneumococcal opsonophagocytic activity (OPA) titers were measured before and 1 month after vaccination.

RESULTS

A second PCV13 given about 4 years after a first vaccination induced OPA titers that were significantly higher than those following the initial vaccination for 7 of 13 serotypes in the older group, and 6 of 13 serotypes in the younger group, and responses to the remaining serotypes were largely non-inferior. In contrast, OPA titers following revaccination with PPSV23 were statistically significantly lower for 9 of the 13 serotypes, and non-inferior for the remaining serotypes, when compared to the responses to the first PPSV23. OPA titers in the older adults who received PPSV23 after initial PCV13 were significantly higher than those following a first PPSV23 for 10 of the 13 serotypes.

CONCLUSION

In adults 50 to 64 years of age, initial vaccination with PCV13 establishes an immune state that results in recall anti-pneumococcal responses upon subsequent vaccination with either conjugated or free polysaccharide vaccine. In contrast, initial vaccination with PPSV23 results in an immune state in which subsequent PPSV23 administration yields generally lower responses compared with the initial responses.

Cost-effectiveness of polysaccharide pneumococcal vaccination in people aged 65 and above in Poland

INTRODUCTION

Invasive pneumococcal disease is associated with substantial morbidity, mortality and cost implications, which could be reduced by vaccination.

AIM

To assess the cost-effectiveness of a 23-valent pneumococcal vaccine in the elderly (65 and older) in Poland.

METHODS

A Markov model with a 1-year cycle length was developed, allowing up to 10 cohorts to enter the model over the lifetime horizon (35 years). In the base case, costs and benefits were assessed using the public health care payer (NFZ) perspective. The analysis included routine vaccination of all elderly and high-risk (HR) elderly versus no vaccination. The analysis assumed that the government would reimburse 50% of the vaccine price. Costs and benefits were discounted 5%, with costs expressed in 2009 Polish Zloty (PLN). Extensive sensitivity analyses were carried out.

RESULTS

PPV23 vaccination targeting all elderly and HR elderly in Poland would avoid 8,935 pneumococcal infections, 2,542 hospitalisations, 671 deaths and 5,886 infections, 1,673 hospitalisations and 441 deaths respectively. The incremental cost per QALY gained would be PLN 3,382 in all elderly and PLN2,148 in HR elderly.

CONCLUSION

Vaccinating adults 65 and older regardless of risk status with a 23-valent pneumococcal vaccine, is cost-effective, resulting in clinical and economic benefits including a non-negligible reduction of ambulatory doctor visits, hospitalizations and, deaths in Poland.