Estimating the transmission parameters of pneumococcal carriage in households

This paper analyses Streptococcus pneumoniae transmission dynamics in households using longitudinal data on pneumococcal (Pnc) carriage in the United Kingdom. Ten consecutive swabs were taken at 4-week intervals from all members of 121 households. The family status is derived from the observed Pnc carriage status of each family member. Transition matrices are built for each family size and composition containing the observed frequency of transitions between family statuses over a 28-day interval. A density-dependent transmission model is fitted to derive maximum-likelihood estimates of the duration of carriage and acquisition rates from the community and from infected individuals within the household. Parameter values are estimated for children (<5 years) and adults (5+years). The duration of carriage is longer in children <5 years of age than in older family members (51 vs. 19 days). Children are 3–4 times more likely than adults to acquire Pnc infection from the community. Transmission rates within the household suggest that adults are more infectious but less susceptible than children. Transmission within the household is most important in large families. The proportion of household-acquired infection ranges from 29 to 46% in households of three persons to 38–50% in larger households. Evidence of density-dependent within-household transmission is found, although the strength of this relationship is not clear from the model estimates

Quality of Health Care for Medicare Beneficiaries: A Chartbook

Provides the results of a review of recently published studies and reports about the quality of health care for elderly Medicare beneficiaries. Includes examples of deficiencies and disparities in care, and some promising quality improvement initiatives

Application of statistical and decision-analytic models for evidence synthesis for decision-making in public health and the healthcare sector

With the awareness that healthcare is a limited resource, decision-makers are challenged to allocate it rationally and efficiently. Health economic methods of evidence synthesis for decision-making are useful to quantify healthcare resource utilisation, critically evaluate different interventions and ensure the implementation of the most effective or cost-effective strategy. The nine studies included in the present cumulative doctoral thesis aim to demonstrate the capability of statistical and decision-analytic modelling techniques to inform and support rational healthcare decision-making in Germany. Five studies apply statistical modelling in analyses of public health and health economic data. They show that the developed models are valuable instruments for examining patterns in the data and generating knowledge from observable data which can further be used in devising disease management and care programs as well as economic evaluations. Further, two health economic evaluations, which adopt the decision-analytic-modelling approach, show that decision-analytic modelling is a powerful tool to represent the epidemiology of infectious and non-infectious diseases on a population level, quantify the burden of the diseases, generalise the outcomes of clinical trials, and predict how the interventions can change the impact of the diseases on the health of the population. Additionally, two literature reviews examine the application of decision-analytic modelling in health economic evaluations. The first study reviews and empirically analyses health technology assessments by the German Institute for Medical Documentation and Information and demonstrates that the application of decision-analytic models improves the evidence produced for policy-making in the healthcare sector in Germany. The second systematic review focuses on methodological choices made in constructing decision-analytic models and explains how critically the structural and parametrical assumptions can influence the final message of the economic evaluations and shows that building a validated, reliable model as well as the transparent reporting is of high priority in facilitating the communication and implementation of the most cost-effective course of action. Overall, the present thesis shows the relevance and advantage of the application of models in synthesising evidence for decision-making. The included studies contribute to the current and future development of the methods used to address the problems of health economic efficiency. Further advances in the computational modelling techniques and data collection, from one side, will ease the decision-making process, but, from another side, will require increasing competence and understanding within the decision-making bodies

Effect measures, their estimation and interpretation : Applications to pneumococcal conjugate vaccination

The direct and indirect effects of pneumococcal vaccination on an individual and the population are of great interest. This study focuses on the definition, estimation and interpretation of different effect measures of vaccines and vaccination against pneumococcal colonisation and disease. Vaccine efficacy, effectiveness and impact are considered as epidemiological parameters of interest which are estimated using observations gathered according to some study design. In this thesis, vaccine efficacy against colonisation is defined through pneumococcal acquisition, which describes the natural process of incident occurrences of colonisation better than prevalence. Moreover, a general definition of vaccine efficacy against a multi-type pathogen is presented, with an epidemiologically meaningful interpretation as a weighted average of strain-specific efficacies. A feasible estimation method is then proposed, based on cross-sectional measurement on the current status of colonisation. When the differences in times at-risk between vaccinated and unvaccinated individuals are taken into account, the estimation of vaccine efficacy against colonisation is shown to be less biased by within-host competition between different serotypes (strains). The estimation method is exemplified with empirical data of pneumococcal colonisation in Israeli children. At the population level, vaccine effectiveness is the measure of vaccine-induced protection during an ongoing vaccination programme when both vaccinated and unvaccinated individuals experience the indirect effects of the vaccination programme. Vaccine impact is the population prevented fraction of the incidence of infection when exposure is the vaccination programme rather than each individual’s own vaccination. Both vaccine effectiveness and impact are parameters that depend on the population dynamics of pneumococcal colonisation and disease after vaccine introduction. In this thesis, the time trends of vaccine effectiveness and impact are described with a pseudo-dynamic model that incorporates the incidences of pneumococcal carriage and disease. The model shows that the effectiveness and impact against vaccine-serotype invasive pneumococcal disease (IPD) are expected to be high and largely of the same magnitude through the post-introduction period. By contrast, the vaccine effectiveness and impact against non-vaccine-serotype IPD follow very divergent paths while the vaccine-type colonisation and disease become eliminated. The practical estimation of vaccine effectiveness is exemplified with register data of Finnish children eligible for pneumococcal conjugate (PCV10) vaccination. Three parallel study designs, the cohort, nested case-control and indirect cohort designs, are shown to provide estimates that are broadly concordant with each other. The parameters of vaccine efficacy as proposed in this thesis can be interpreted as measures of the biological effect of the vaccine on new vaccine-type acquisitions and should therefore allow more robust comparisons across different epidemiological settings with differing levels of exposure by non-vaccine strains. Moreover, the thesis helps to interpret the time-varying parameters of vaccine impact and effectiveness during large-scale vaccinations, and their manifestation in Finnish children.Pneumokokkirokotusten yksilöön ja koko väestöön kohdistuvat suorat ja epäsuorat vaikutukset on tärkeää tuntea. Tämä tutkimus keskittyy pneumokokkirokotteiden tehomittojen määritelmiin, estimointiin ja tulkintaan. Rokotteen teho ennen rokotusohjelman aloittamista sekä teho ja vaikuttavuus ohjelman aikana ovat kiinnostavia parametreja, jotka estimoidaan keräämällä havaintoja jonkin koeasetelman mukaisesti. Työssä tarkastellaan pneumokokkirokotteen tehoa nenänielukantajuutta vastaan kantajuuden ilmaantuvuuden kautta. Ilmaantuvuus kuvaa kantajuuden biologista luonnetta paremmin kuin sen esiintyvyys, mutta vaatii tyypillisesti pitkittäismittauksia. Työssä osoitetaan, että rokotusteho kantajuuden ilmaantuvuutta vastaan voidaan estimoida poikkileikkausaineistosta odds-suhteena. Lisäksi näytetään, että kun rokotusteho määritellään patogeenille, jolla on monta alatyyppiä kuten pneumokokille, on huomioitava eri alatyyppien keskinäinen kilpailu nenänielussa. Tällöin rokotustehon estimaatti vastaa tarkemmin todellista rokotustehoa. Tätä havainnollistetaan israelilaisten päiväkotilasten kantajuusmittausten avulla. Laajamittaisen rokotusohjelman aikana rokotusteho mittaa rokotteen yksilölle tarjoamaa suoraa suojaa tilanteessa, jossa sekä rokotetut että rokottamattomat lapset kokevat myös epäsuoria vaikutuksia (laumasuojaa ja ei-rokotetyyppien korvautumista). Rokotusohjelman vaikuttavuus mittaa kantajuuden tai taudin ilmaantuvuuden muutosta verrattuna tilanteeseen ennen rokotusohjelmaa. Sekä rokotusteho että vaikuttavuus ovat parametreja, jotka riippuvat pneumokkikantajuuden ja -taudin väestödynamiikasta. Rokotustehon ja vaikuttavuuden aikatrendejä kuvataan pseudodynaamisella mallilla, joka ottaa huomioon kantajuuden ja taudin ilmaantuvuuden muutokset ajassa. Mallin mukaan sekä rokotusteho että vaikuttavuus rokotetyypin vakavaa pneumokokkitautia vastaan pysyvät korkeina ja liki samansuuruisina koko rokotusohjelman ajan. Sitä vastoin rokotusteho ja vaikuttavuus ei-rokotetyypin vakavaa pneumokokkitautia vastaan ovat hyvin erisuuruiset silloin, kun rokotetyypin kantajuus on vähentynyt ja poistumassa väestöstä. Rokotustehon estimointia havainnollistetaan käyttäen suomalaista terveysrekisteriaineistoa vakavan pneumokokkitaudin tapauksista lapsilla, jotka ovat oikeutettuja pneumokokkirokotusohjelmaan. Kolmen tutkimusasetelman eli kohortti-, pesäytetyn tapaus-verrokki- ja epäsuoran kohorttiasetelman näytetään tarjoavan likimain samansuuruisia estimaatteja. Esitetyt rokotustehon parametrit nenänielukantajuutta vastaan tarjoavat mahdollisuuden verrata rokotetutkimuksia erilaisissa asetelmissa, vaikka ei-rokotetyypin kantajuuden ilmaantuvuus voi vaihdella paljonkin. Lisäksi tutkimus tarjoaa keinoja tulkita ajassa muuttuvia rokotustehon ja vaikuttavuuden mittoja laajojen rokotusohjelmien aikana, erityisesti suomalaisten lasten näkökulmasta

The impact of 10-valent and 13-valent pneumococcal conjugate vaccines on hospitalization for pneumonia in children: A systematic review and meta-analysis

Abstract Background This systematic review and meta-analysis aimed at summarizing available data on the impact of PCV10 and PCV13 in reducing the incidence of CAP hospitalizations in children aged Methods A systematic search of the literature was conducted. We included time-series analyses and before-after studies, reporting the incidence of hospitalization for pneumonia in the periods before and after the introduction of PCV10 or PCV13 into the immunization program. Pooled estimates of Incidence Rate Ratio (IRR) were calculated by using a random-effects meta-analytic model. Results were stratified according to age-groups ( Results A total of 1533 potentially relevant articles were identified. Of these, 12 articles were included in the analysis. In children aged In children aged 24–59 months, the meta-analysis showed a reduction of 9% (95%CI: 5–14%, p-value High heterogeneity was detected among studies evaluating the hospitalization rate for clinically and radiologically confirmed pneumonia. Conclusions The results of this study revealed a significant impact of PCV10 and PCV13 in reducing the hospitalizations for pneumonia, particularly in children age

Prev Chronic Dis

IntroductionDiabetes is a chronic disease that requires complex continuing medical care and patient self-management to reduce the risk of long-term complications. Receipt of multiple recommended preventive care services can prevent or delay diabetes-related complications such as blindness and lower-extremity amputations.MethodsWe analyzed 1997 and 2007 Behavioral Risk Factor Surveillance System data to examine change in rates of adults with diabetes receiving 4 essential preventive care services (influenza and pneumococcal vaccinations and annual foot and eye examinations).ResultsThe overall age-adjusted rate of receiving all 4 of the preventive care services was 10% in 1997 but increased to 20% in 2007. Rates for receiving all 4 services increased significantly in all demographic subgroups except Hispanics.ConclusionUse of preventive care services is increasing, but most US adults with diabetes do not meet recommendations, and the problem is particularly pronounced among Hispanics. The need to receive preventive care services should continue to be emphasized in clinical and community settings to increase the percentage of adults with diabetes who receive them.2010720

Infant mortality rates and pneumococcal vaccines: a time-series trend analysis in 194 countries, 1950–2020

Pneumonia due to Streptococcus pneumoniae (pneumococcus) is a major cause of mortality in infants (children under 1 year of age), and pneumococcal conjugate vaccines (PCVs), delivered during the first year of life, are available since the year 2000. Given those two premises, the conclusion follows logically that favourable impact reported for PCVs in preventing pneumococcal disease should be reflected in the infant mortality rates (IMRs) from all causes. Using publicly available datasets, country-level IMR estimates from UNICEF and PCV introduction status from WHO, country-specific time series analysed the temporal relationship between annual IMRs and the introduction of PCVs, providing a unique context into the long-term secular trends of IMRs in countries that included and countries that did not include PCVs in their national immunisation programmes. PCV status was available for 194 countries during the period 1950–2020: 150 (77.3%) of these countries achieved nationwide PCV coverage at some point after the year 2000, 13 (6.7%) achieved only partial or temporary PCV coverage, and 31 (15.9%) never introduced PCVs to their population. One hundred and thirty-nine (92.7%) of countries that reported a decreasing (negative) trend in IMR, also reported a strong correlation with decreasing maternal mortality rates (MMRs), suggesting an improvement in overall child/ mother healthcare. Conversely, all but one of the countries that never introduced PCVs in their national immunisation programme also reported a decreasing trend in IMR that strongly correlates with MMRs. IMRs have been decreasing for decades all over the world, but this latest decrease may not be related to PCVs

The impact of educational interventions on influenza and pneumococcal vaccination rates in primary care

Background. Influenza and pneumococcal vaccinations are important therapies supported by national and international guidelines for preventing morbidity and mortality from respiratory illnesses in high-risk groups. The responsibility for delivering these vaccinations in the United Kingdom lies with primary care. Little is known about how rates of influenza and pneumococcal vaccination can be increased in high-risk groups in primary care. Aim. To research methods of improving rates of influenza and pneumococcal vaccination in high-risk groups in primary care. Objectives. To investigate the impact of educational interventions for primary care teams on influenza and pneumococcal vaccination rates in high-risk groups. Method. The research had the following components: a. Literature search examining current practice and policy in relation to influenza and pneumococcal vaccination and studies undertaken to improve performance, both in general and specifically in relation to improving adult vaccination rates. b. Pilot study of targeting influenza and pneumococcal vaccination to high-risk groups in a single general practice. c. Effect of audit and feedback with an information pack to primary care teams on influenza and pneumococcal vaccination in primary care: before-and-after multipractice study. d. Effect of audit and feedback with an information pack to primary care teams, as part of a clinical governance programme, on influenza and pneumococcal vaccination in a primary care trust: before-and-after multipractice study. e. Randomised controlled study of an educational outreach intervention partly nested within primary care trust study with audit, feedback and information (passive dissemination of guidelines and recommendations) directed at primary health care teams compared with audit feedback and information alone using multifaceted interventions to increase influenza and pneumococcal vaccine uptake in high-risk groups in primary care. Results. The studies demonstrated significant improvements in influenza and pneumococcal vaccination rate in high-risk groups in primary care, showed the levels of improvement that could be expected from these types of intervention and described how primary care teams responded to direct and indirect educational interventions supported by measurement of performance. Conclusions. Education to multiprofessional teams is an important method for diffusion of innovations in the highly professionalised organisations of primary care and general practice. Educators need to understand the complex nature of primary care organisations and teams, when and how education for teams is likely to be successful, the barriers to implementation of new ideas and how to address these. Education when applied appropriately can have important effects in improving health care. This is more likely to occur when careful assessments are made around the nature of the evidence, clear outcomes are sought and measured and the healthcare intervention is understood from the perspective of the patient, the healthcare team and other stakeholders