Differences in the Impact of Pneumococcal Serotype Replacement in Individuals With and Without Underlying Medical Conditions.
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ABSTRACT: Background
Pneumococcal conjugate vaccines (PCVs) have had a well-documented impact on the incidence of invasive pneumococcal disease (IPD). However, declines in IPD due to vaccine-targeted serotypes have been partially offset by increases in IPD due to nonvaccine serotypes (NVTs). The goal of this study was to quantify serotype-specific changes in the incidence of IPD that occurred in different age groups, with or without certain comorbidities, following the introduction of 7-valent pneumococcal conjugate vaccine (PCV7) and 13-valent pneumococcal conjugate vaccine (PCV13) in the childhood vaccination program in Denmark.Methods
We used nationwide surveillance data for IPD and a hierarchical Bayesian regression framework to estimate changes in the incidence of IPD associated with the introduction of PCV7 (2007) and PCV13 (2010) while controlling for serotype-specific epidemic cycles and unrelated secular trends.Results
Following the introduction of PCV7 and PCV13 in children, the net impact of serotype replacement varied considerably by age group and comorbidities. Differences in the magnitude of serotype replacement were due to variations in the incidence of NVTs in the different risk groups before the introduction of PCVs. The relative increases in the incidence of IPD caused by specific NVTs did not differ appreciably between risk groups in the postvaccination period. Serotype replacement offset a greater proportion of the benefit of PCVs in strata in which the NVTs comprised a larger proportion of cases prior to the introduction of the vaccines.Conclusions
These findings could help to predict the impact of next-generation PCVs in specific risk groups.
SUBMITTER: Weinberger DM
PROVIDER: S-EPMC6579958 | biostudies-literature |
REPOSITORIES: biostudies-literature
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| S-EPMC2507715 | biostudies-literature
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| S-EPMC10615641 | biostudies-literature
Project description:The seven-valent pneumococcal conjugate vaccine (PCV7) was added to the UK national immunisation programme in September 2006. PCV13 replaced PCV7 in April 2010. As carriage precedes disease cases this study collected carried pneumococci from children each winter from 2006/7 to 2010/11 over PCV introduction. Conventional microbiology and whole genome sequencing were utilised to characterise pneumococcal strains. Overall prevalence of pneumococcal carriage remained stable. Vaccine serotypes (VT) decreased (p<0.0001) with concomitant increases in non-vaccine serotypes (NVT). In winter 2010/11 only one isolate of PCV7 VT was observed (6B). PCV13 unique VTs decreased between winters immediately preceding and following PCV13 introduction (p=0.04). Significant decreases for VTs 6B, 19F, 23F (PCV7) and 6A (PCV13) and increases for NVT 21, 23B, 33F and 35F were detected. The serotype replacement was accompanied by parallel changes in genotype prevalence for associated sequence types with clonal expansion contributing to replacement. By winter 2010/11, serotype coverage of PCV7 and PCV13 was 1% and 11% respectively. VT replacement was observed for PCV7 and PCV13 serotypes. Conjugate vaccine design and use requires continuous monitoring and revision.
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Project description:OBJECTIVES:To quantify the risk of pneumococcal pneumonia (PP) and invasive pneumococcal disease (IPD) in adults aged ?19 years with underlying medical conditions compared with healthy adults of the same age in Japan. DESIGN:An observational, retrospective, cohort study using two healthcare claims databases in Japan: Japan Medical Data Center (JMDC) and Medical Data Vision (MDV) databases. PARTICIPANTS:A total of 10.4?million individuals, representing 9.3?million person-years of follow-up, were included in the analysis. Eleven medical conditions as well as PP and IPD were identified by the International Statistical Classification of Diseases and Related Health Problems version 10 diagnostic codes and/or local disease codes used in Japan. PRIMARY OUTCOME MEASURES:Adjusted rate ratios (RRs) for PP and IPD in adults with a medical condition versus adults without any medical condition were calculated using multivariate Poisson regression models with age and/or sex as covariates. RESULTS:In the JMDC and MDV databases, respectively, adults ?19 years with a medical condition (RRs for PP: 3.3 to 13.4, 1.7 to 5.2; RRs for IPD: 12.6 to 43.3, 4.4 to 7.1), adults with two or more medical conditions (PP: 11.6, 2.8; IPD: 18.7, 5.8) and high-risk adults (PP: 12.9, 1.8; IPD: 29.7, 4.0) were at greater risk of PP and IPD compared with their healthy counterparts. Adults aged 50-64 years with an underlying medical condition (PP rate: 38.6 to 212.1 per 100?000 person-years) had a higher rate of PP than those aged ?65 years without any condition (PP rate: 13.2 to 93.0 per 100?000 person-years). CONCLUSIONS:Adults of all ages with an underlying medical condition are at greater risk of PP and IPD compared with adults without any medical condition. This risk increases with the number of underlying medical conditions. Our results support extending pneumococcal vaccination to younger adults with an underlying medical condition, especially those aged 50-64 years.
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Project description:BACKGROUND: Although it is widely accepted that adults with immunocompromising conditions are at greatly increased risk of pneumococcal infection, the extent of risk among immunocompetent adults with chronic medical conditions is less certain, particularly in the current era of universal vaccination of children with pneumococcal conjugate vaccines. METHODS: We conducted a retrospective cohort study using data from 3 healthcare claims repositories (2006-2010) to compare rates of pneumococcal disease in immunocompetent adults with chronic medical conditions ("at-risk") and immunocompromised adults ("high-risk"), with rates in adults without these conditions ("healthy"). Risk profiles and episodes of pneumococcal disease-all-cause pneumonia, pneumococcal pneumonia, and invasive pneumococcal disease (IPD)-were ascertained from diagnosis, procedure, and drug codes. RESULTS: Rates of all-cause pneumonia among at-risk persons aged 18-49 years, 50-64 years, and ?65 years were 3.2 (95% confidence interval [CI], 3.1-3.2), 3.1 (95% CI, 3.1-3.1), and 3.0 (95% CI, 3.0-3.0) times the rates in age-matched healthy counterparts, respectively. We identified rheumatoid arthritis, systemic lupus erythematosus, Crohn's disease, and neuromuscular or seizure disorders as additional at-risk conditions for pneumococcal disease. Among persons with at-risk conditions, the rate of all-cause pneumonia substantially increased with the accumulation of concurrent at-risk conditions (risk stacking): among persons 18-49 years, rate ratios increased from 2.5 (95% CI, 2.5-2.5) in those with 1 at-risk condition to 6.2 (95% CI, 6.1-6.3) in those with 2 conditions, and to 15.6 (95% CI, 15.3-16.0) in those with ?3 conditions. Findings for pneumococcal pneumonia and IPD were similar. CONCLUSIONS: Despite widespread use of pneumococcal conjugate vaccines, rates of pneumonia and IPD remain disproportionately high in adults with at-risk conditions, including those with conditions not currently included in the Advisory Committee on Immunization Practices' guidelines for prevention and those with multiple at-risk conditions.
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Project description:Invasive pneumococcal disease (IPD), caused by infection with Streptococcus pneumoniae, has a substantial global burden. There are over 90 known serotypes of S. pneumoniae with a considerable body of evidence supporting serotype-specific mortality rates immediately following IPD. This is the first study to consider the association between serotype and longer-term mortality following IPD. Using enhanced surveillance data from the North East of England we assessed both the short-term (30-day) and longer-term (⩽7 years) independent adjusted associations between individual serotypes and mortality following IPD diagnosis using logistic regression and extended Cox proportional hazards models. Of the 1316 cases included in the analysis, 243 [18·5%, 95% confidence interval (CI) 16·4-20·7] died within 30 days of diagnosis. Four serotypes (3, 6A, 9N, 19 F) were significantly associated with overall increased 30-day mortality. Effects were observable only for older adults (⩾60 years). After extension of the window to 12 months and 36 months, one serotype was associated with significantly increased mortality at 12 months (19 F), but no individual serotypes were associated with increased mortality at 36 months. Two serotypes had statistically significant hazard ratios (HR) for longer-term mortality: serotype 1 for reduced mortality (HR 0·51, 95% CI 0·30-0·86) and serotype 9N for increased mortality (HR 2·30, 95% CI 1·29-4·37). The association with serotype 9N was no longer observed after limiting survival analysis to an observation period starting 30 days after diagnosis. This study supports the evidence for associations between serotype and short-term (30-day) mortality following IPD and provides the first evidence for the existence of statistically significant associations between individual serotypes and longer-term variation in mortality following IPD.
| S-EPMC4988273 | biostudies-literature
Project description:IntroductionLimited changes in serotype 3 invasive pneumococcal disease (IPD) incidence rates after a decade of 13-valent pneumococcal conjugate vaccine (PCV13) introduction into several national immunization programs (NIP) have raised questions about PCV13's effectiveness against this serotype.MethodsWe analyzed the impact of pediatric PCV programs on serotype 3 IPD with two approaches. First, we reviewed the publicly available surveillance data from countries identified in two recently published reviews to describe the population impact of pediatric PCV13 or PCV10 vaccination programs on serotype 3 IPD. We then compared the observed trends in PCV10 and PCV13 countries to a previously described dynamic transmission model that simulates the spread of pneumococcal carriage and development of IPD in a population over time.ResultsWhen serotype 3 disease rates are compared from countries that have introduced either a 10-valent (PCV10) vaccine that does not contain serotype 3 in its formulation or PCV13 in their pediatric NIP, over time, serotype 3 incidence rate trends are markedly different. Countries with a PCV10 NIP showed a substantial linear increase in serotype 3 pneumococcal disease among all age groups since the time of PCV10 introduction, whereas countries with a PCV13 NIP experienced a modest decline during the 3-4 years after vaccine introduction followed by an inflection upward in subsequent years.ConclusionThese data suggest that PCV13 provides a certain degree of direct and indirect protection against serotype 3 at the population level and direct adult vaccination with a serotype 3-containing vaccine is likely to provide substantial benefit in the context of a pediatric PCV NIP. Further research around serotype 3 transmission patterns and epidemiology is nonetheless warranted.
| S-EPMC7954992 | biostudies-literature
Project description:Clinical, immunological and microbiological characteristics of recurrent invasive pneumococcal disease (IPD) in children were evaluated, differentiating relapse from reinfection, in order to identify specific risk factors for both conditions.All patients <18 years-old with recurrent IPD admitted to a tertiary-care pediatric center from January 2004 to December 2011 were evaluated. An episode of IPD was defined as the presence of clinical findings of infection together with isolation and/or pneumococcal DNA detection by Real-Time PCR in any sterile body fluid. Recurrent IPD was defined as 2 or more episodes in the same individual at least 1 month apart. Among recurrent IPD, we differentiated relapse (same pneumococcal isolate) from reinfection.593 patients were diagnosed with IPD and 10 patients died. Among survivors, 23 episodes of recurrent IPD were identified in 10 patients (1.7%). Meningitis was the most frequent form of recurrent IPD (10 episodes/4 children) followed by recurrent empyema (8 episodes/4 children). Three patients with recurrent empyema caused by the same pneumococcal clone ST306 were considered relapses and showed high bacterial load in their first episode. In contrast, all other episodes of recurrent IPD were considered reinfections. Overall, the rate of relapse of IPD was 0.5% and the rate of reinfection 1.2%. Five out of 7 patients with reinfection had an underlying risk factor: cerebrospinal fluid leak (n = 3), chemotherapy treatment (n = 1) and a homozygous mutation in MyD88 gene (n = 1). No predisposing risk factors were found in the remainder.recurrent IPD in children is a rare condition associated with an identifiable risk factor in case of reinfection in almost 80% of cases. In contrast, recurrent IPD with pleuropneumonia is usually a relapse of infection.
| S-EPMC4349703 | biostudies-other
Project description:BackgroundPneumococcal colonization is a precursor to pneumonia, and pneumococcal conjugate vaccines (PCV) can decrease vaccine-type (VT) colonization. Pneumococcal colonization studies are traditionally done among healthy children in the community; however, VT colonization prevalence may differ between these children and those with pneumonia. We assessed overall and VT pneumococcal colonization and factors associated with colonization among children with and without pneumonia after Mozambique introduced 10-valent PCV (PCV10) in 2013.MethodsWe used data from ongoing pneumonia surveillance in children aged <5 years and from cross-sectional nasopharyngeal colonization surveys conducted in October 2014 -April 2015 and October 2015 -May 2016. Pneumonia was defined using WHO standard criteria for radiologically confirmed pneumonia. Children with pneumonia enrolled from January 2014 -April 2016 were compared to children without pneumonia enrolled from the cross-sectional surveys. Clinical data and nasopharyngeal (NP) swabs were collected from each child. NP specimens were cultured for pneumococci, and culture-negative specimens from children with pneumonia underwent polymerase chain reaction (PCR).ResultsOf 778 and 927 children with and without pneumonia, 97.4% and 27.0% were exposed to antibiotics before swab collection, respectively. Based on culture, pneumococcal colonization was 45.1% for children with and 84.5% for children without pneumonia (P<0.001); VT pneumococcal colonization was 18.6% for children with and 23.4% for children without pneumonia (P = 0.02). The addition of PCR in children with pneumonia increased overall and VT-pneumococcal colonization to 79.2% and 31.1%, respectively. In multivariable analysis including PCR results, pneumonia was associated with VT pneumococcal colonization (adjusted OR: 1.4, 95%CI: 1.10-1.78).ConclusionVaccine-type pneumococcal colonization remains common among children with and without pneumonia post-PCV10 introduction in Mozambique. In a population of children with high antibiotic exposure, the use of PCR for culture-negative NP swabs can improve assessment of pneumococcal colonization and circulating serotypes.
| S-EPMC6019677 | biostudies-literature