PPV23 Vaccination Research Articles

Effectiveness of the 23-valent pneumococcal polysaccharide vaccine against invasive pneumococcal disease in people aged 65 years and over in the North East of England, April 2006–July 2012

The 23-valent pneumococcal polysaccharide vaccine (PPV23) is recommended for all aged ⩾65 years in the UK to help reduce the burden of invasive pneumococcal disease (IPD). A total of 728 IPD cases aged ⩾65 years were diagnosed between 1 April 2006 and 31 July 2012 in the North East of England. Crude vaccine effectiveness (VE) estimates for PPV23 were calculated using the indirect-cohort method using a stratified analysis. VE for persons aged ⩾65 years was 28.5% (95% confidence interval: −17.4%, 56.5%). PPV23 was less effective in older age groups at IPD diagnosis and for those vaccinated at an older age. Estimates of VE published since the introduction of PPV23 appear to show a decrease in VE over time, possibly due to changes in demographics, circulating serotypes and vaccine formulation. An effective PPV23 vaccination programme should continue in those aged ⩾65 years in the North East of England.

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.

Value of adult PPV23 vaccination validated in Germany . . .

Value of adult PPV23 vaccination validated in Germany . . .

Cost–effectiveness of vaccinating adults with the 23-valent pneumococcal polysaccharide vaccine (PPV23) in Germany

The introduction of routine infant vaccination against pneumococcal disease has resulted in a decreased overall invasive pneumococcal disease incidence in adults but also a change in invasive pneumococcal disease serotypes. This study aimed to assess the cost–effectiveness of 23-valent pneumococcal polysaccharide vaccine (PPV23) in Germany in this context. A population-based Markov model was developed. A cohort of adults currently eligible for vaccination was followed until death. Adult vaccination with PPV23 was associated with an incremental cost–effectiveness ratio of €17,065/quality-adjusted life years gained from the third-party payer’s perspective. Univariate sensitivity analyses showed that the incremental cost–effectiveness ratio was below €50,000/quality-adjusted life years gained in most test scenarios. The model suggests that adult PPV23 vaccination is cost effective in Germany, due to its broad serotype coverage. This is despite epidemiological changes in Streptococcus pneumoniae serotypes caused by wider use of pneumococcal conjugate vaccines during childhood.

Vaccinating welders against pneumonia

In 2011, the Department of Health in England recommended that welders should each receive a single dose of the 23-valent pneumococcal polysaccharide vaccine (PPV23). To assess the evidence behind the advice and its practical implications. The review was informed by a systematic search in Medline, which related pneumonia to welding and/or exposure to metal fume, and was supplemented using the personal libraries of the authors. There is consistent evidence that welders die more often of pneumonia, especially lobar pneumonia, are hospitalized more often for lobar and pneumococcal pneumonia, and more often develop invasive pneumococcal disease (IPD). It is estimated that one case of IPD may be prevented over a 10-year period by vaccinating 588 welders against pneumococcal infection. A good case exists that employers should offer PPV23 vaccination to welders and other employees exposed to metal fume. Additionally, reasonable measures must be taken to minimize exposure to welding fume, and welders should be encouraged not to smoke.

Use of pneumococcal polysaccharide vaccine in children

Pneumococcal glycoconjugate vaccines (PCVs) are now widely used in infant immunization schedules. These vaccines are also recommended for those at increased risk of pneumococcal infection and to provide optimal serotype coverage to those at increased risk of disease. The 23-valent polysaccharide vaccine (PPV23) is often advised from the second birthday to provide broader serotype coverage. The use of pneumococcal polysaccharide vaccines (PPVs) has in recent years become a topic of much debate, especially for use in children. Although no effect of PPV23 on carriage has been reported, some protection against invasive pneumococcal disease (IPD) is possible. There is a theoretical risk of memory B-cell depletion to PCV serotypes following PPV23 vaccination, even in PCV-primed children, but the clinical significance is currently unknown. This risk is increased by PPV23 revaccination. Whether the immune response to PPV23, non-PCV13 serotypes is sufficient to confer clinical benefit to at-risk children depends on their age, underlying disease and the immunogenicity of individual serotypes. Given the theoretical risk of memory B-cell depletion following PPV23 vaccination, it is not clear how best to maintain protection in those at-risk children who remain susceptible to IPD.

Potential cost-effectiveness and benefit-cost ratios of adult pneumococcal vaccination in Germany.

BackgroundInvasive (IPD, defined as detection of pneumococci in sterile body fluids like meningitis or bacteremic pneumonia) and non-invasive Streptococcus pneumoniae infections (i.e. non-bacteremic pneumonia, otitis media) in adults are associated with substantial morbidity, mortality and costs. In Germany, Pneumococcal polysaccharide vaccination (PPV23) is recommended for all persons >60 years and for defined risk groups (age 5–59). The aim of this model was to estimate the potential cost-effectiveness and benefit-cost ratios of the adult vaccination program (18 years and older), considering the launch of the pneumococcal conjugate vaccine for adults (PCV13).MethodsA cross-sectional steady state Markov model was developed to estimate the outcomes of PCV13, PPV23 vaccination schemes and ‘no vaccination’. Conservative assumptions were made if no data were available for PCV13 and PPV23 respectively. The effectiveness of individual pneumococcal vaccination in adults was adjusted for expected indirect effects due to the vaccination in infants. Data on incidences, effectiveness and costs were derived from scientific literature and publicly available databases. All resources used are indicated. Benefit-cost ratios and cost-effectiveness were evaluated from the perspective of the German Statutory Health Insurance as well as from social perspective.ResultsUnder the assumption that PCV13 has a comparable effectiveness to PCV7, a vaccination program with PCV13 revealed the potential to avoid a greater number of yearly cases and deaths in IPD and pneumonia in Germany compared to PPV23. For PCV13, the costs were shown to be overcompensated by monetary savings resulting from reduction in the use of health care services. These results would render the switch from PPV23 to PCV13 as a dominant strategy compared to PPV23 and ‘no vaccination’. Given the correctness of the underlying assumptions every Euro spent on the PCV13 vaccination scheme yields savings of 2.09 € (social perspective: 2.16 €) compared to PPV23 and 1.27 € (social perspective: 1.32 €) compared to ‘no vaccination’, respectively.ConclusionsResults of the model indicate that the health economic benefit of immunizing adults with PCV13 can be expected to outperform the sole use of PPV23, if the effectiveness of PCV13 is comparable to the effectiveness of PCV7.

Cost-effectiveness of the introduction of the pneumococcal polysaccharide vaccine in elderly Colombian population

BackgroundStreptococcus pneumoniae causes community-acquired pneumonia, otitis media and meningitis, with higher incidences at the extremes of life. PPV-23 vaccine is widely used in prevention of pneumonia and invasive pneumococcal disease in older adults in developed countries. We developed an evaluation of cost-effectiveness of implementing PPV-23 in Colombian population over 60 years. MethodsThe number of cases of pneumonia and meningitis in patients over 60 years and the proportion by S. pneumoniae was estimated based on a review of literature. A decision tree model with a 5-year time horizon was built to evaluate the cost-effectiveness of the implementation of the PPV-23 in this population. Direct health care costs of out- and in-patients were calculated based on expenditure records from the Bogota public health system. Incremental cost-effectiveness ratios per life saved and per year of life gained were estimated based on the decision tree model. Deterministic and probabilistic sensitivity analyses were performed. ResultsWithout vaccination 4460 (range 2384–8162) bacteremic pneumococcal pneumonias and 141 (range 73–183) pneumococcal meningitis would occur among people over 60 years old in Colombia. In the first year, vaccination with PPV-23 at US$8/dose would save 480 (range 100–1753) deaths due to Invasive and non-invasive pneumococcal disease. Vaccination would results in US$3400/deaths averted (range US$1028–10,862) and US$1514/life years gained (range US$408–5404). ConclusionVaccination with PPV-23 in over 60 years is a highly cost-effective public health measure in Colombia. Despite some limitations, the results are robust, and may help developing countries to perform informed decisions about the introduction of the vaccine.

Pneumococcal polysaccharide vaccination for adults: new perspectives for Europe

Vaccination is the only public-health measure likely to reduce the burden of pneumococcal diseases. In 2010, a group of European experts reviewed evidence on the burden of pneumococcal disease and the immunogenicity, clinical effectiveness and cost–effectiveness of vaccination with 23-valent pneumococcal polysaccharide vaccine (PPV23). They also considered issues affecting the future use of PPV23 and pneumococcal conjugate vaccines in the elderly and adults at high risk of pneumococcal disease. PPV23 covers 80–90% of the serotypes responsible for invasive pneumococcal disease in Europe. Primary vaccination and revaccination with PPV23 are well tolerated, induce robust, long-lasting immune responses in elderly adults and are cost effective. Ensuring protection against pneumococcal disease requires monitoring of the changing epidemiology of pneumococcal serotypes causing invasive pneumococcal disease and improving vaccine coverage. In the future, it will be critically important for pneumococcal vaccination recommendations for elderly adults to be based on comparative evaluations of PPV23 and newer pneumococcal conjugate vaccines with regard to their long-term immunogenicity, clinical effectiveness and cost–effectiveness.

Mortality reductions for older adults differ by race/ethnicity and gender since the introduction of adult and pediatric pneumococcal vaccines.

We determined the effectiveness of a 23-valent-polysaccharide pneumococcal vaccine (PPV-23) and pneumococcal conjugate vaccine (PCV-7) in reducing adult pneumococcal mortality by comparing historically predicted declines in pneumococcal disease mortality with observed patterns since the introduction of PPV-23 and PCV-7, including analyses of age, gender, and racial/ethnic subgroups. We analyzed all deaths registered on U.S. death certificates reporting any site of pneumococcal infection (e.g., meningitis, sepsis, pneumonia, bacteremia, and peritonitis) from 1968 to 2006. We used time-series dynamic linear regression on annual pneumococcal mortality rates to determine the percentage reduction in post-1983 mortality rates for a given increase in PPV-23 vaccination rates and post-2000 mortality rates for a given increase in PCV-7 vaccination rates. Pneumococcal mortality decreased well before the introduction of PPV-23 in 1983 and again before the introduction of PCV-7 in 2000. The level of PPV-23 vaccination was associated with a direct and significant reduction in adult mortality, especially white female adults > or = 65 years of age. In contrast, the level of PCV-7 vaccination in the population was not associated with an indirect and significant reduction in pneumococcal mortality beyond the historical pace of decline. PPV-23 introduction was associated with a reduction in pneumococcal mortality among older adults > or = 65 years of age beyond levels predicted by secular trends, whereas PCV-7 introduction was not. Mortality reduction was not uniformly experienced across the population, revealing the need for additional strategies to reduce pneumococcal mortality in older adults.

Response to conjugate pneumococcal and Haemophilus influenzae type b vaccines in asplenic patients

We determined the immunogenicity of conjugated Haemophilus influenzae type b and pneumococcal vaccines by quantitative analysis of the antibody response in asplenic patients. To that end, we vaccinated 92 patients with a conjugated Hib vaccine and 54 received two doses of conjugated pneumococcal vaccine (PCV7), followed at six months by a plain polysaccharide pneumococcal vaccine (PPV23). Antibody concentrations were measured before and three weeks after vaccination. After one dose of pneumococcal conjugate vaccine, 46% of the patients reached the antibody threshold of ≥1.0μg/mL for all 7 tested vaccine serotypes. This percentage rose to 54% after the second dose of PCV7 and did not increase further after PPV23. Over 90% of patients had antibody concentrations ≥1.0μg/mL for at least 5 out of the 7 conjugated pneumococcal serotypes after 2 doses of PCV7. For serotypes, included in the PPV23 vaccine only, 25% (PPS3)–100% (PPS19A) of the patients reached antibody concentrations ≥1.0μg/mL after one dose of PPV23. For Hib, 97% of the patients reached the threshold concentration of ≥1.0μg/mL after one dose of vaccine. It can be concluded that the majority of asplenic patients had a sufficient response to conjugated vaccines against Streptococcus pneumoniae and Hib, reflected by a ≥1.0μg/mL antibody response. Inclusion of conjugated pneumococcal polysaccharide vaccines might be of additional value in the vaccination schedule for asplenic patients because of their high immunogenicity.

Acute epiglottitis: epidemiology and Streptococcus pneumoniae serotype distribution in adults

We studied the incidence and bacterial epidemiology of acute epiglottitis presenting in the first 16 years following the introduction of general childhood vaccination against Haemophilus influenzae type b. Our main objectives were to analyse (1) the incidence of Streptococcus pneumoniae epiglottitis in adults and (2) the distribution of pneumococcal serotypes involved. The medical records of patients with acute epiglottitis (International Classification of Disease code J05.1) were investigated. Streptococcus pneumoniae serotyping was performed using gel precipitation. The overall incidence of acute epiglottitis was 0.98 cases/100,000/year, compared with 4.5 cases/100,000/year before the vaccination programme. The incidence was reduced both in children and adults, compared with pre-vaccination values. However, the incidence of Streptococcus pneumoniae epiglottitis in adults increased from 0.1 to 0.28 cases/100,000/year over the same time period. The causative agent was Streptococcus pneumoniae in 10 adults. Nine of 10 pneumococcal strains could be serotyped. All but one serotype is represented in the 23-valent pneumococcal polysaccharide vaccine (PPV23) used in adults. In acute epiglottitis, now a disease of adults, the most important bacterial aetiology is Streptococcus pneumoniae. The serotype distribution found in this study indicates that the infection is preventable by PPV-23 vaccination with the 23-valent polysaccharide vaccine.

Concomitant administration of zoster and pneumococcal vaccines in adults ≥60 years old

This study evaluated safety & immunogenicity of ZOSTAVAX® (zoster vaccine: ZV) administered concomitantly versus nonconcomitantly with PNEUMOVAX® 23 (pneumococcal vaccine: PPV23). This randomized, double-blind, placebo-controlled study enrolled 473 subjects ≥60 years old in 1:1 ratio to receive ZV & PPV23 concomitantly (Day 1) or nonconcomitantly (PPV23 Day 1, ZV Week 4). Blood samples obtained for pneumococcal polysaccharide (PnPs) antibody (Ab) testing by enzyme-linked immunosorbent assay (ELISA) and varicella-zoster virus (VZV) Ab testing by glycoprotein ELISA. Subjects followed for adverse experiences (AEs) for 28 days postvaccination. Mean baseline VZV geometric mean titers (GMT) in nonconcomitant group were lower than concomitant group. Four weeks postvaccination with ZV, VZV Ab response in concomitant group was not similar to nonconcomitant group; estimated VZV GMT ratio [concomitant/nonconcomitant] was 0.70 (95% CI, 0.61-0.80). VZV Ab response was acceptable in concomitant group; estimated geometric mean foldrise (GMFR) from baseline was 1.9 (95% CI, 1.7-2.1). PnPs serotype-specific Ab responses were similar in both groups. All 6 reported serious AEs were deemed not related to study vaccine. Postvaccination of ZV, incidence of injection-site AEs was similar in both groups; clinical AEs were numerically but not significantly higher in nonconcomitant group. In summary, VZV GMT Ab response induced by ZV administered concomitantly with PPV23 was inferior to that induced nonconcomitantly. These results indicate that, to avoid a potential decrease in ZV immunogenicity, ZV & PPV23 should not be given concomitantly. Concomitant administration did not affect response to PPV23 serotypes tested. When administered concomitantly, ZV & PPV23 vaccines were generally well tolerated.

Pneumococcal vaccine in the elderly: a useful but forgotten vaccine

Pneumococcal disease in the elderly is a major concern emphasizing the need for prevention. The review focuses on a literature-based analysis of the efficacy ("does the vaccine works?") and/or the effectiveness ("does vaccination help older population?") of pneumococcal vaccines 14- or 23-valent (PPV23) in the elderly. In the setting of Streptococcus pneumoniae pneumonia, there is still no conclusive evidence decisively confirming the efficacy of pneumococcal vaccine against pneumococcal pneumonia in the elderly populations. However, the efficacy of pneumococcal vaccination has been demonstrated in the prevention of invasive pneumococcal disease (IPD) such as bacteremia, which is the main complication of pneumonia. In the setting of IPD in the elderly, analysis of the current literature provides evidence for both the efficacy and effectiveness of PPV23, but most of the clinical studies failed to demonstrate a substantial reduction in all-cause mortality rate. The community-acquired pneumonia guidelines in the industrialized countries include recommendations for pneumococcal vaccine by PPV23 for adults aged 65 years and over. Taking into account the preventive effect of PPV23 on IPD and the threat of a pandemic flu, the increase of PPV23 vaccination coverage in elderly patients should be strongly considered.

Compliance with Immunizations in Splenectomized Individuals: A Study of the Splenectomized Hereditary Spherocytosis Population

Overwhelming infection by encapsulated bacteria is a significant short- and longterm risk of splenectomy. Vaccines are available for organisms to which asplenic patients are susceptible, i.e. S. pneumoniae, N. meningitidis, and H. influenza-B. Therefore, strict adherence to the immunizations against these organisms is recommended. In addition, after splenectomy, antibiotic prophylaxis is advised, although guidelines for chemoprophylaxis are not consistent across hematology and surgical disciplines.METHODS: We performed a cross sectional study to determine immunization status, antibiotic use, and patient knowledge after splenectomy in the hereditary spherocytosis (HS) population. Subjects were ascertained from the recent and archival records of the hematology, surgery, and pathology departments at Children's Hospital Boston. Addresses of former patients were sought by public record review and through current patient/family members. A strategy of expanding families by phone contact for this genetic disorder (commonly autosomal dominant) allowed ascertainment of older relatives of current patients. Vaccine status was by self- or parental-report.RESULTS: We enrolled 77 splenectomized HS patients (38% male, mean age 34.7 y, mean age at splenectomy 10.9 y). Of the asplenic HS patients interviewed, only 20 (26%) reported receiving all of the recommended post-splenectomy vaccines (Table 1). However, 65% of splenectomized individuals reported that a physician had told them that their immunizations were up-to-date. Among the asplenic HS patients, the likelihood of receiving a particular vaccine was related to the number of years the vaccine had been available: PPV23 vaccine (1977) 96% > MPSV4 (1981) 78% > Hib (1987) 64% > PCV7 (2000) 42% > MCV4 (2005) 27%. As expected, asplenic patients < age 20 y were much more likely to have received the new conjugate vaccines than older adults (PCV 83% vs. 23%, P<0.001; MCV4 87% vs. 17%, P<0.001; Hib 96% vs. 52%; P<0.001). Of the 77 splenectomized individuals, 44 stated that they had taken prophylactic antibiotics following splenectomy. Of these 44, 25% stopped prophylaxis within the year of splenectomy. There were 14 reported cases of serious infection (sepsis, bacterial meningitis, or bacterial pneumonia) in splenectomized patients. Of these, 2/14 were up-to-date for immunizations. 13 of the 93 unsplenectomized individuals experienced serious infection (difference N.S.). 22 of 77 splenectomized patients interviewed were unaware of their immunization status, and approximately 75% of patients were not up-to-date on all currently recommended vaccinations. These numbers may reflect lack of patient knowledge about the risk of infection following splenectomy, and they demonstrate room for substantial improvement in pre-and post-splenectomy management of HS patients, whose splenectomies are virtually always planned and elective. Preoperative immunization is key, and pediatric hematology clinics have a unique opportunity to ascertain and provide catch-up and booster vaccinations to splenectomized adult relatives of their patients. A greater effort must be made by hematologists, primary care providers, and surgeons to educate patients about the risks of splenectomy, and the positive contributions that immunizations provide in protecting asplenic individuals from infection.Table 1. Summary of adherence to immunizationsPCV7PPV23MCV4MPSV4InfluenzaHibAll Recommended Immunizations32/7774/7721/7760/7767/7749/7720/77PCV7, Pneumococcal Conjugate Vaccine; PPV23, Pneumococcal Polysaccharide Vaccine; MCV4, Meningococcal Conjugate Vaccine; MPSV4, Meningococcal Polysaccharide Vaccine; Hib, Haemophilus influenza Type B Conjugate Vaccine

PROTRACTED FEVER WITH CELLULITIS-LIKE REACTION IN PNEUMOCOCCAL POLYSACCHARIDE-VACCINATED CHILDREN

Side effects of the 23-valent pneumococcal polysaccharide vaccine (PPV23) are regarded as mild and uncommon in adults. In our clinical experience, however, protracted fever with a cellulitis-like reaction after PPV23 vaccination is not rare in pediatric patients. We reviewed the records of 17 children with those clinical findings after PPV23 vaccination.

Invasive pneumococcal infections among persons with and without underlying medical conditions: Implications for prevention strategies

BackgroundThe 23-valent pneumococcal polysaccharide vaccine (PPV23) is recommended for persons aged < 65 years with chronic medical conditions. We evaluated the risk and mortality from invasive pneumococcal disease (IPD) among persons with and without the underlying medical conditions which are considered PPV23 indications.MethodsPopulation-based data on all episodes of IPD (positive blood or cerebrospinal fluid culture) reported by Finnish clinical microbiology laboratories during 1995–2002 were linked to data in national health care registries and vital statistics to obtain information on the patient's preceding hospitalisations, co-morbidities, and outcome of illness.ResultsOverall, 4357 first episodes of IPD were identified in all age groups (average annual incidence, 10.6/100,000). Patients aged 18–49 and 50–64 years accounted for 1282 (29%) and 934 (21%) of IPD cases, of which 372 (29%) and 427 (46%) had a current PPV23 indication, respectively. Overall, 536 (12%) IPD patients died within one month of first positive culture. Persons aged 18–64 years accounted for 254 (47%) of all deaths (case-fatality proportion, 12%). Of those who died 117 (46%) did not have a vaccine indication. In a survival model, patients with alcohol-related diseases, non-haematological malignancies, and those aged 50–64 years were most likely to die.ConclusionIn the general population of non-elderly adults, almost two-thirds of IPD and half of fatal cases occurred in persons without a recognised PPV23 indication. Policymakers should consider additional prevention strategies such as lowering the age of universal PPV23 vaccination and introducing routine childhood pneumococcal conjugate immunisation which could provide substantial health benefits to this population through indirect vaccine effects.

The 23-valent pneumococcal polysaccharide vaccine does not provide additional serotype antibody protection in children who have been primed with two doses of heptavalent pneumococcal conjugate vaccine

Current guidelines recommend up to two doses of the pneumococcal conjugate heptavalent vaccine (PCV-7) in children up to 5 years old followed by and a dose of the polysaccharide vaccine (PPV-23) for patients over 2 years old to broaden serotype immunity. We assessed the serotype responses to two doses of PCV-7 and a dose of PPV-23 in a cohort of children in the 2-16-year age range in order to determine whether PPV-23 induced effective immunity to non-PCV-7 serotypes. Pneumococcal antibody concentrations to the seven serotypes covered by PCV-7 and five additional serotypes covered by PPV-23 but not PCV-7 were measured in 60 children aged 2-16 years. None of the children had a primary antibody immunodeficiency. Vaccinated children had 7-30-fold higher antibody concentrations than unvaccinated children to all serotypes contained in the PCV-7 (P<0.001). In contrast, serotypes covered by the PPV-23 but not PCV-7 were only one- to two-fold higher and there was no significant increase in the number of children who had protective concentrations of antibody (> or =0.35 mcg/ml) against these serotypes. In this cohort of children, PPV-23 vaccine did not broaden the protection in vitro against potentially pathogenic strains of Streptococcus pneumoniae. We call into question the recommendation to use the PPV-23 in children.

Invasive pneumococcal disease epidemiology and effectiveness of 23-valent pneumococcal polysaccharide vaccine in Alaska Native adults

Alaska Native persons have age-adjusted invasive pneumococcal disease (IPD) rates two- to three-fold greater than non-Native Alaskans. To characterize IPD epidemiology and 23-valent polysaccharide pneumococcal vaccine (PPV-23) effectiveness in Alaska Native adults we reviewed IPD cases from Alaska-wide, laboratory-based surveillance. Sterile site isolates were serotyped. Vaccine effectiveness (VE) was estimated using the indirect cohort method. 394 cases (44.5 cases/100,000/year) occurred in 374 Alaska Native adults (36.0% aged ≥55 years). Underlying conditions included heavy alcohol use (65.7%), smoking (60.8%) and COPD (25.0%). Overall VE was 75% (95% confidence interval [CI]: 27%, 91%) but declined with increasing age; for persons ≥55 years (VE = <0; 95% CI: <0, 78%; p = 0.713). Alaska Native adults experience high rates of IPD. The majority of IPD cases occurred in persons with underlying conditions and behaviors associated with increased risk of IPD in other populations. PPV-23 vaccine effectiveness was confirmed in younger Alaska Native adults but not among adults ≥55 years.

Declining invasive pneumococcal disease in the U.S. elderly

In 2000, pneumococcal conjugate vaccine (PCV7) was recommended for young children. By 2002–2003, 48.6% had been fully immunized. Using Medicare administrative, we found that the rates of invasive pneumococcal disease (IPD) hospitalizations in the elderly in the 2000–2001, 2001–2002 and 2002–2003, were 22.6, 30.2, and 40.6% lower, respectively, than during the baseline period, 1996–1997 through 1999–2000 (range 35.1/100,000 to 38.3/100,000). Pneumococcal polysaccharide vaccine (PPV23) has been recommended for the elderly, since 1989. PPV23 vaccination rates in the elderly increased by 25.2% during the baseline period but by <5% during the period PCV7 has been available. Thus, during the period that PCV7 vaccine has been used in children, rates of IPD in the elderly have declined appreciably more compared to the immediately prior period when PPV23 was the only vaccine available.