Why the recent ACIP recommendations regarding conjugate pneumococcal vaccine in adults may be irrelevant

Immunizing hearts: exploring the vaccination frontier in heart failure management

Heart failure (HF) is a widespread clinical condition that affects numerous individuals globally and is a leading cause of hospitalization, particularly in the elderly population. Despite efforts to manage HF using various pharmacological and nonpharmacological interventions, mortality and hospitalization rates remain alarmingly high. Preventive vaccination has emerged as a key measure endorsed by cardiology societies for reducing the morbidity and mortality associated with HF. This study undertakes an extensive review of existing literature to explore the role of vaccination in managing HF, focusing specifically on the immunological pathways involved and potential benefits offered by immunization in this context. This article highlights the role of various vaccines, including influenza, pneumococcal, and COVID-19 vaccines, in reducing HF-related hospitalization, mortality, and overall disease burden. Additionally, this article will delve into specific vaccines that have shown promise in HF management, such as influenza, pneumococcal, and COVID-19 vaccines, along with the rationale for their use, clinical trials, meta-analyses, and real-world data supporting their effectiveness in patients with HF. This article also considers potential challenges and obstacles to widespread vaccination in individuals with HF, which include vaccine hesitancy, accessibility, and adverse events related to vaccines.

Sequential administration of Prevnar 13™ and PNEUMOVAX™ 23 in healthy participants 50 years of age and older

In most countries worldwide, pneumococcal conjugate vaccines have been included in the infant immunization program, resulting in a significant reduction in the burden of pneumococcal disease in children and adults. Shifting serotype distribution due to the indirect effect of infant vaccination with the 13-valent pneumococcal conjugate vaccine (PCV13) may continue to increase the gap between 23-valent pneumococcal polysaccharide vaccine (PPSV23) and PCV13 serotype coverage for older adults in the coming years. This clinical study (V110-029; NCT02225587) evaluated the safety and immunogenicity of sequential administration of PCV13 followed approximately 8 weeks later, or approximately 26 weeks later, by PPSV23 in healthy adults ≥50 years of age. Both dosing intervals were generally well tolerated as measured by the nature, frequency, and intensity of reported adverse events (AEs) in both vaccination groups. Serotype-specific opsonophagocytic activity (OPA) geometric mean titers (GMTs) measured 30 days following receipt of PPSV23 in either group and at Week 30 were generally comparable between the 2 groups for 6 serotypes unique to PPSV23 and 12 serotypes shared between PCV13 and PPSV23, regardless of the interval between receipt of PCV13 and PPSV23. In addition, administration of PPSV23 given either 8 weeks or 26 weeks following PCV13 did not negatively impact immune responses induced by PCV13. Furthermore, administration of PPSV23 given either 8 weeks or 26 weeks after PCV13 elicited serotype-specific OPA GMTs to serotypes unique to PPSV23, which could provide earlier protection against pneumococcal disease caused by these serotypes in comparison with the current Advisory Committee on Immunization Practices recommended interval of at least 12 months.

Pneumococcal Conjugate Vaccination Followed by Pneumococcal Polysaccharide Vaccination in Lung Transplant Candidates and Recipients

Background

Pneumococcal conjugate vaccination as well as pneumococcal polysaccharide vaccination are recommended for lung transplant candidates and recipients, but the combination of these vaccines has not been extensively studied in these specific populations.

Methods

Lung transplant candidates and recipients were vaccinated with a 13-valent pneumococcal conjugate vaccine, followed 8 weeks later by a pneumococcal polysaccharide vaccine. Pneumococcal antibody levels against 13 pneumococcal serotypes were measured and followed up after 1 year in the transplant recipients. These values were compared with a historical control group vaccinated with the polysaccharide vaccine alone.

Results

Twenty-five lung transplant candidates and 23 lung transplant recipients were included. For the majority of serotypes, there was no significant increase in antibody levels after additional vaccination with the polysaccharide vaccine in both patient groups. When compared with the historical control group, the antibody response in lung transplant recipients 1 year after vaccination did not seem to have improved by vaccination with both vaccines instead of the polysaccharide vaccine alone.

Conclusions

Serologic vaccination responses in lung transplant candidates and recipients were not improved by giving a 23-valent pneumococcal polysaccharide vaccine after a 13-valent pneumococcal conjugate vaccine. The benefit of this vaccination schedule in lung transplant recipients seems to differ from other immunocompromised populations. The optimal vaccination schedule for lung transplant candidates and recipients remains to be determined.

Influence of immune aging on vaccine responses

Impaired vaccine responses in older individuals are associated with alterations in both the quantity and quality of the T-cell compartment with age. As reviewed herein, the T-cell response to vaccination requires a fine balance between the generation of inflammatory effector T cells versus follicular helper T (TFH) cells that mediate high-affinity antibody production in tandem with the induction of long-lived memory cells for effective recall immunity. During aging, we find that this balance is tipped where T cells favor short-lived effector but not memory or TFH responses. Consistently, vaccine-induced antibodies commonly display a lower protective capacity. Mechanistically, multiple, potentially targetable, changes in T cells have been identified that contribute to these age-related defects, including posttranscription regulation, T-cell receptor signaling, and metabolic function. Although research into the induction of tissue-specific immunity by vaccines and with age is still limited, current mechanistic insights provide a framework for improved design of age-specific vaccination strategies that require further evaluation in a clinical setting.

An Adjuvant That Increases Protective Antibody Responses to Polysaccharide Antigens and Enables Recall Responses

Protection against encapsulated bacteria can be elicited using polysaccharide vaccines. These antigens often behave as T-cell-independent type 2 antigens (TI-2 Ags). However, TI-2 Ags, including pneumococcal polysaccharides, often elicit weak immunoglobulin G (IgG) responses and are refractive to boosting. Conjugate vaccines have not completely overcome this challenge and hence, alternative strategies are required to enhance polysaccharide vaccine responses. Herein, we describe an adjuvant consisting of a Toll-like receptor and C-type lectin receptor agonist pairing that significantly increases primary immunoglobulin M and IgG responses to TI-2 Ags as well as enables significant boosting when coadministered with polysaccharide vaccines. Consistent with this, the adjuvant significantly increased the generation of both TI-2 memory B cells and long-lived antibody secreting cells. Adjuvant effects were highly dependent on B-cell-intrinsic MyD88, but not Trif expression. Importantly, coadministration of the adjuvant with the Pneumovax vaccine significantly increased the protective efficacy of vaccination in a lethal challenge mouse model of pneumococcal respiratory infection. Collectively, these data provide evidence that B-cell-directed adjuvants have promise in significantly improving the quality and quantity of serologic and B-cell memory responses to clinically relevant polysaccharide vaccines.

Impact of pneumococcal conjugate vaccines on hospitalizations for pneumonia in the United States

INTRODUCTION

Pneumonia is one of the leading causes of morbidity and mortality among children and older adults. Pneumococcal conjugate vaccines (PCVs) were introduced into the US routine infant vaccination schedule leading to substantial reductions of invasive pneumococcal diseases (IPD). PCV introduction also led to reductions in all-cause pneumonia among US children, though the indirect impact of PCVs on pneumonia in adults is difficult to quantify, especially due to the recent US recommendation for direct PCV use in older adults. Areas covered: We described the existing evidence for both the direct and indirect impact of PCVs on pneumonia among children and adults in the US since PCV introduction. Expert commentary: The introduction of PCVs into the US routine infant vaccination schedule led to important reductions in the burden of IPD and non-invasive pneumonia among vaccinated and unvaccinated populations. The impact of direct vaccination of older adults in the US since 2014, though difficult to quantify, is currently being evaluated. As pneumonia remains one of the leading causes of morbidity and mortality in the US, future evaluations of the direct and indirect effects of current and expanded valency PCVs in the US population are needed.

Immunogenicity of pneumococcal vaccines in comorbid autoimmune and chronic respiratory diseases

Streptococcus pneumoniae causes pneumonia, meningitis, otitis media, and bacteremia. The mortality and morbidity of invasive pneumococcal disease are high among adults aged >65 years or those with underlying chronic or immunosuppressive conditions. A recent systematic review showed that patients treated with immunosuppressive agents have impaired immune responses to pneumococcal conjugate vaccine (PCV) and pneumococcal polysaccharide vaccine compared with healthy subjects. A more favorable response is observed in patients treated with tumor necrosis factor-alpha-blocking agents compared with those treated with other immunosuppressive agents. Low systemic corticosteroid doses do not affect the responses to pneumococcal vaccines. Patients with human immunodeficiency virus and idiopathic pulmonary fibrosis receiving immunosuppressive therapy exhibit decreased immunogenicity to pneumococcal vaccines. The effects of T-cell-dependent PCV possibly depend on host memory B cells in some disease conditions. Several immunosuppressive therapy types and disease conditions may affect the responses to pneumococcal vaccines. Immunization should be administered before immunosuppressive medication initiation whenever possible.

Decision-making for PCV in adults

Thirteen-valent pneumococcal conjugate vaccine (PCV13) was licensed in adults to address the unmet medical need of vaccine-type community acquired pneumonia (CAP) and the limitations of previous plain-polysaccharide vaccines. Since then, some have questioned the utility of adult PCV13 use, arguing that: i) high PCV13 uptake in young children would provide indirect effects that, by themselves, would sufficiently protect unvaccinated adults and ii) no data describing the real-world effectiveness of PCV13 use in adults, especially with immunocompromising conditions, exist. Even in countries like the United States where PCV13 has been routinely recommended for all adults aged ≥ 65 years, the recommendation is contingent on a re-evaluation to determine if continued use is needed in the context of a mature PCV13 pediatric immunization program. Emerging evidence, however, suggests that i) a meaningful burden of PCV13-type pneumococcal pneumonia still persists in adults at increased risk for pneumococcal disease, despite indirect effects from long-standing pediatric PCV13 use, ii) adult PCV13 use is effective and has reduced pneumococcal CAP, even in the elderly and those with chronic medical or immunocompromising conditions – and disease could come back if PCV13 were removed, and iii) ethical and pragmatic vaccine policy considerations support continued adult PCV13 use in countries that have already introduced the vaccine (eg, disparities in adult PCV13 uptake, confusion stemming from removing a previously-recommended vaccine for a non-safety-related concern, and the reality that next-generation PCVs are only a few years away). Together, these findings suggest that continued PCV13 vaccination in adults is needed to control vaccine-type CAP.

The effect of immunosuppressive agents on immunogenicity of pneumococcal vaccination: A systematic review and meta-analysis

INTRODUCTION

Patients with a weakened immune system due to immunosuppressive treatment are at increased risk of infection with Streptococcus pneumoniae. Although pneumococcal vaccination is highly recommended for those patients, the effectiveness of pneumococcal vaccination in this population remains largely unknown. Therefore, the objective of this PROSPERO-registered systematic review and meta-analysis was to evaluate the effect of the most commonly prescribed immunosuppressive agents such as azathioprine, methotrexate, anti-Tumor Necrosis Factor α (TNFα), or rituximab, on the initial serologic response to pneumococcal vaccination in patients with auto-immune disease.

METHODS

We included 22 articles comprising 2077 patients, of whom 1623 were treated with immunosuppressive agents, and 454 were controls.

RESULTS AND DISCUSSION

The findings of our systematic review indicate that, in patients treated with immunosuppressive medication and compared to controls, the initial serologic response to pneumococcal conjugate vaccine (PCV) and pneumococcal polysaccharide vaccine (PPSV) are impaired. Moreover, this impaired response was more profound after PCV than after PPSV. We hypothesize that the immunosuppressive medication mainly compromises the cellular immunity, explaining the more severely reduced response rate to PCV (which induces a T-cell dependent immune response), compared to PPSV. Treatment with TNFα blocking agents was associated with a more favorable response, compared to patients treated with other immunosuppressive medication. Targeted research applying uniform correlates of protection is needed to bridge the knowledge gap in vaccination immunology in this patient group. PROSPERO registration: CRD42017058364.

Economic evaluation of pneumococcal vaccines for adults aged over 50 years in Belgium

Streptococcus pneumoniae causes a high disease burden including pneumonia, meningitis and septicemia. Both a polysaccharide vaccine targeting 23 serotypes (PPV23) and a 13-valent conjugate vaccine (PCV13) are indicated for persons aged over 50 years. We developed and parameterized a static multi-cohort model to estimate the incremental cost-effectiveness and budget-impact of these vaccines at different uptake levels. Using three different vaccine efficacy scenarios regarding non-invasive pneumococcal pneumonia and extensive uni- and multivariate sensitivity analyses, we found a strong preference for PPV23 over PCV13 in all age groups at willingness to pay levels below €300 000 per quality adjusted life year (QALY). PPV23 vaccination would cost on average about €83 000, €60 000 and €52 000 per QALY gained in 50-64, 65-74 and 75-84 year olds, whereas for PCV13 this is about €171 000, €201 000 and €338 000, respectively. Strategies combining PPV23 and PCV13 vaccines were most effective but generally less cost-effective. When assuming a combination of increased duration of PCV13 protection, increased disease burden preventable by PCV13 and a 75% reduction of the PCV13 price, PCV13 could become more attractive in <75 year olds, but would remain less attractive than PPV23 from age 75 years onwards. These observations are independent of the assumption that PPV23 has 0% efficacy against non-invasive pneumococcal pneumonia. Pneumococcal vaccination would be most cost-effective in Belgium, when achieving high uptake with PPV23 in 75-84 year olds, as well as by negotiating a lower market-conform PPV23 price to improve uptake and cost-effectiveness.

Evaluating clinical effectiveness of 13-valent pneumococcal conjugate vaccination against pneumonia among middle-aged and older adults in Catalonia: results from the EPIVAC cohort study

Background

Benefits using the 13-valent pneumococcal conjugate vaccine (PCV13) in adults are controversial. This study investigated clinical effectiveness of PCV13 vaccination in preventing hospitalisation from pneumonia among middle-aged and older adults.

Methods

Population-based cohort study involving 2,025,730 individuals ≥50 years in Catalonia, Spain, who were prospectively followed from 01/01/2015 to 31/12/2015. Primary outcomes were hospitalisation for pneumococcal or all-cause pneumonia and death from any cause. Cox regression models were used to evaluate the association between PCV13 vaccination and the risk of each outcome, adjusting for age, sex and major comorbidities/underlying risk conditions.

Results

Cohort members were observed for a total of 1,990,701 person-years, of which 6912 person-years were PCV13 vaccinated. Overall, crude incidence rates (per 100,000 person-years) were 82.8 (95% confidence interval [CI]: 77.7–88.1) for pneumococcal pneumonia, 637.9 (95% CI: 599.0–678.7) for all-cause pneumonia and 2367.2 (95% CI: 2222.8–2518.7) for all-cause death. After multivariable adjustments we found that the PCV13 vaccination did not alter significantly the risk of pneumococcal pneumonia (multivariable-adjusted hazard ratio [mHR]: 1.17; 95% CI: 0.75–1.83; p = 0.493) and all-cause death (mHR: 1.07; 95% CI: 0.97–1.18; p = 0.190), although it remained significantly associated with an increased risk of all-cause pneumonia (mHR: 1.69; 95% CI: 1.48–1.94; p < 0.001). In stratified analyses focused on middle-aged or elderly persons and immunocompromised or immunocompetent subjects, PCV13 vaccination did not appear effective either.

Conclusion

Our data does not support clinical benefits of PCV13 vaccination against pneumonia among adults in Catalonia. It must be closely monitored in future studies involving more vaccinated person-time at-observation.

[Antipneumococcal vaccination in Catalonian adults: Vaccine coverages and adequacy to distinct guideline recommendations]

OBJECTIVES

To know antipneumococcal vaccination coverages among Catalonian adults and evaluate the adequacy of vaccine use according to 3 distinct current vaccination guidelines.

DESIGN

Population-based cross-sectional study.

SETTING

Primary Health Care. Catalonia, Spain.

PARTICIPANTS

A total of 2,033,465 individuals≥50 years-old registered in the Catalonian Health Institute.

MAIN MEASUREMENTS

Vaccination status for the 23-valent pneumococcal polysaccharide vaccine (PPV23) and/or the 13-valent pneumococcal conjugate vaccine (PCV13) was revised at 1/01/2015. Adequacy of vaccination status was determined according to 3 distinct vaccination recommendation guidelines: Spanish Ministry of Health (basically coinciding with Catalonian Health Institute's recommendations), Spanish Society of Family Physicians (semFYC) and Centers for Disease Control and Prevention (CDC).

RESULTS

Overall, 789,098 (38.8%) persons had received PPV23 and 5,031 (0.2%) had received PCV13. PPV23 coverage largely increased with increasing age (4.8% in 50-59 years, 35.5% in 60-69 years, 71.9% in 70-79 years and 79.5% in≥80 years; P<.001), whereas PCV13 coverage was very small in all age groups. Considering the 3 analysed vaccine guidelines a 46.1% of the overall study population were adequacy vaccinated according to Spanish Ministry's recommendations, 19.3% according to semFYC's recommendations and 4.6% according to CDC's recommendations.

CONCLUSION

PPV23 coverage among Catalonian adults may be considered as intermediate, but PCV13 coverage is very small. The institutional recommendations (Spanish Ministry) are more followed than corporative (semFYC) or less local (CDC) recommendations in clinical practice.

Prevalence of high, medium and low-risk medical conditions for pneumococcal vaccination in Catalonian middle-aged and older adults: a population-based study

BACKGROUND

Updated population-based data on the frequency and distribution of risk factors for pneumococcal disease is scarce. This study investigated the prevalence of distinct comorbidities and underlying risk conditions related to an increasing risk of pneumococcal disease among Catalonian middle-aged and older adults.

METHODS

Cross-sectional population-based study including 2,033,465 individuals aged 50 years or older registered at 01/01/2015 in the Catalonian Health Institute (Catalonia, Spain). The clinical research database of the Information System for the Development of Research in Primary Care (SIDIAP database) was used to identify high-risk (asplenia and/or immunocompromising conditions) and other increased-risk conditions (chronic pulmonary, cardiac or liver disease, diabetes mellitus, alcoholism and/or smoking) among study subjects.

RESULTS

Globally, 980,310 (48.2%) of the 2,033,465 study population had at least one risk condition of suffering pneumococcal disease (55.4% in men vs 42.0% in women, p < 0.001; 41.7% in people 50-64 years vs 54.7% in persons 65 years or older, p < 0.001). An amount of 176,600 individuals (8.7%) had high-risk conditions (basically immunocompromising conditions). On the other hand, 803,710 persons (39.5%) had one or more other risk conditions. In fact, 212,255 (10.4%) had chronic pulmonary diseases, 248,377 (12.2%) cardiac disease, 41,734 (2.1%) liver disease, 341,535 (16.8%) diabetes mellitus, 58,781 (2.9%) alcoholism and 317,558 (15.6%) were smokers.

CONCLUSION

In our setting, approximately 50 % of overall persons 50 years or older may be considered at-risk population for pneumococcal disease (almost 10 % have high-risk conditions and 40 % have other risk conditions).

Pneumococcal conjugate vaccine use in adults - Addressing an unmet medical need for non-bacteremic pneumococcal pneumonia

Streptococcus pneumoniae is a frequent cause of community acquired pneumonia (CAP), with the largest burden of disease attributed to non-bacteremic pneumonia. Due to the high persistent burden of disease, pneumococcal pneumonia, particularly non-bacteremic pneumococcal pneumonia, continues to be a major public health concern. There are currently two pneumococcal vaccines approved for use in adults in the United States (US) and other countries worldwide: a 23-valent pneumococcal simple polysaccharide vaccine (PPV23), and a 13-valent pneumococcal conjugate vaccine (PCV13). The capsular polysaccharides included in PPV23 induce antibodies primarily by a T-cell independent mechanism, thus the immune response is short lived and lacks the ability to elicit an anamnestic response. PCV13, on the other hand, has the bacterial polysaccharides covalently conjugated to an immunogenic carrier protein resulting in the formation of memory B lymphocytes, thus proving long-acting immunologic memory and an anamnestic response. Despite 30years of use, the question of PPV23 vaccine efficacy, particularly with respect to efficacy for non-bacteremic pneumonia, has been extensively debated and investigated; whereas PCV13 efficacy against vaccine-type pneumococcal CAP, both bacteremic and non-bacteremic, was confirmed in a large randomized controlled trial in older adults. PCV13 was approved under the US Food and Drug Administration's accelerated pathway, which allows for earlier approval of products that provide meaningful benefit over existing treatments - in this case, protection of adults from non-bacteremic pneumococcal pneumonia. Its use is now increasingly recommended globally. This article summarizes the history and use of PPV23 and PCV13 in adults and how vaccination of adults with PCV13 addresses an unmet medical need.

The herd effects of infant PCV7/PCV13 sequential implementation on adult invasive pneumococcal disease, six years post implementation; a nationwide study in Israel

BACKGROUND

Introduction of pneumococcal conjugate vaccine (PCV) has nearly eliminated vaccine-type (VT) invasive pneumococcal disease (IPD) in children, yet the reported resulting reduction of adult IPD is variable. We present the indirect impact of sequential PCV7/PCV13 implementation in Israel on adult IPD.

METHODS

An ongoing nationwide active surveillance was initiated on July 2009 when PCV7 was implemented (with Catch-up). PCV7 was gradually replaced by PCV13 since November 2010. Comorbidity and outcome data were collected from medical files. Incidence rates were calculated for overall and vaccine-type IPD.

RESULTS

A total of 2579 IPD cases were diagnosed among a population of 5.0-5.5 million adults >18y (2009-2015). Incidence rates were 9.15/100,000 and 10.16/100,000 in the first and second study years, respectively. However, after PCV13 implementation, the rates decreased to 7.19 within four years, and remained stable in the two following years. Within 6years, PCV7-VT-IPD incidence decreased from 2.52 to 0.52 (79%) and PCV13-VT-IPD from 6.15 to 1.81 (71%). Concurrently, non-VT13 incidence increased from 2.99 to 5.25. Approximately 50% of all patients were adults ≥65y, in whom the decrease in PCV13-VT-IPD incidence was smaller and slower (65% vs. >80% decrease in adults <50y).

CONCLUSIONS

Despite continued reduction in PCV13-VT-IPD, overall IPD was stable during the last two years due to serotype replacement. Yet, the significant decrease in adult IPD, six years post-PCV7/13 implementation emphasizes the importance of indirect protection in achieving overall population impact and should be considered when discussing the potential additional benefits of direct adult PCV vaccination.

Pneumococcal vaccination coverages among low-, intermediate-, and high-risk adults in Catalonia

There is scarce data about pneumococcal vaccination coverages among adults in recent years. We investigated current pneumococcal vaccination coverages in Catalonia, Spain, with a cross-sectional population-based study including 2,033,465 individuals aged 50 y or older assigned to the Catalonian Health Institute at 01/01/2015 (date of survey). A previously validated institutional research clinical Database was used to classify study subjects by their vaccination status for both 23-valent pneumococcal polysaccharide vaccine (PPSV23) and 13-valent pneumococcal conjugate vaccine (PCV13), to identify comorbidities and underlying conditions, and establish the risk stratum of each individual: High risk stratum: functional or anatomic asplenia, cochlear implants, CSF leaks, or immunocompromising conditions; medium risk stratum: immunocompetent persons with history of chronic cardiac or respiratory disease, liver disease, diabetes mellitus, alcoholism and/or smoking; low risk stratum: persons without high or medium risk conditions. Of the total 2,033,465 study population, an amount of 789,098 (38.8%) had received PPVS23, whereas 5031 (0.2%) had received PCV13. PPSV23 coverages increased largely with increasing age: 4.8% in 50-59 y vs 35.5% in 60-69 y vs 71.9% in 70-79 y vs 79.5% in 80 y or older; p < 0.001). PCV13 coverages also increased with age, although they were very low in all age groups. PPSV23 coverages were 59.2% in high risk stratum, 48.3% in medium risk stratum and 28.1% in low risk stratum (p < 0.001). For the PCV13, uptakes were 1.2%, 0.3% and 0.1% in high, medium and low stratum, respectively (p < 0.001). In conclusion, pneumococcal vaccination coverages in Catalonian adults are not optimal, being especially small for the PCV13 (even in high-risk subjects).

What do we know about the cost-effectiveness of pneumococcal conjugate vaccination in older adults?

The cost-effectiveness of 13-type pneumococcal conjugate vaccine (PCV13) use in older adults, and the relative merits when compared to the 23-type polysaccharide pneumococcal vaccine (PPV23), has been a topic of much debate. Although a number of economics evaluations have been conducted many of these were completed before the availability of critical data on PCV13 efficacy in older adults. Recent studies using this data have found conflicting results. This may in part reflect differences in the level of herd protection from infant pneumococcal vaccination programs in different countries. The costs and benefits of pneumococcal vaccination in adults are likely to rest on several critical parameters: the magnitude pneumococcal disease in older adults and the serotypes responsible for it, the efficacy of each vaccine against invasive and non-invasive pneumonia, the duration of vaccine protection, and differences in vaccine price. The ongoing changes in pneumococcal disease patterns highlight the need for economic evaluations to use recent serotype-specific disease estimates from the setting under consideration. In countries that do recommend PCV13 use in adults, post-implementation economic evaluation (using data from after a program is implemented) may be useful to help inform potential future changes to vaccine recommendations as well as the maximum price that should be paid for the vaccines in future negotiations.

Pneumococcal conjugate vaccine in adults: Let's see what happens

The recent recommendation for the use of the 13-valent pneumococcal conjugate vaccine (PCV13) in adults 65 y of age and older, provides a new tool for preventing disease in this at-risk population. The conjugate vaccine induces a T-cell dependent response, which distinguishes it from the polysaccharide vaccine and could provide the longer-term protection necessary to have a significant impact in this population.

Other age groups than children need to be considered as carriers of Streptococcal pneumoniae serotypes

We need to raise the issue that focus on children as the only carriage group for pneumococci is not optimal; we need to consider that other age groups might also be carriers of pneumococcal serotypes causing invasive pneumococcal diseases (IPD) in unvaccinated age groups. The pneumococcal conjugate vaccines (PCV) have successfully removed IPD from vaccinated children. Studies have shown an effect of PCV reducing the pneumococcal carriage of PCV serotypes in children. The status for several countries having used PCV for many years is that they do not see PCV serotypes neither carried nor as a cause of IPD in children. PCV vaccination of children has shown a herd protection effect in unvaccinated groups as a reduction in IPD cases caused by PCV serotypes. However, not all PCV serotypes have disappeared as the cause of IPD in the unvaccinated age groups. The author therefore believes that if we are to see PCV serotypes disappear as a cause of IPD in unvaccinated age groups, we need to perform further carriage studies to examine carriage in other age groups. Alternatively, all age groups should be vaccinated against pneumococci to eliminate IPD caused by PCV serotypes from possible hidden carriers.