Estimating the coronavirus disease-2019 (COVID-19) infection fatality rate (IFR) has proven to be particularly challenging –and rather controversial– due to the fact that both the data on deaths and the data on the number of individuals infected are subject to many different biases. We consider a Bayesian evidence synthesis approach which, while simple enough for researchers to understand and use, accounts for many important sources of uncertainty inherent in both the seroprevalence and mortality data. With the understanding that the results of one's evidence synthesis analysis may be largely driven by which studies are included and which are excluded, we conduct two separate parallel analyses based on two lists of eligible studies obtained from two different research teams. The results from both analyses are rather similar. With the first analysis, we estimate the COVID-19 IFR to be 0.31% [95% credible interval (CrI) of (0.16%, 0.53%)] for a typical community-dwelling population where 9% of the population is aged over 65 years and where the gross-domestic-product at purchasing-power-parity (GDP at PPP) per capita is $17.8k (the approximate worldwide average). With the second analysis, we obtain 0.32% [95% CrI of (0.19%, 0.47%)]. Our results suggest that, as one might expect, lower IFRs are associated with younger populations (and may also be associated with wealthier populations). For a typical community-dwelling population with the age and wealth of the United States we obtain IFR estimates of 0.43% and 0.41%; and with the age and wealth of the European Union, we obtain IFR estimates of 0.67% and 0.51%.

Dietary guidelines should be underpinned by the best available evidence on relationships between diet and health, including evidence from nutrient-based, food-based and dietary patterns research. The primary aim of the present study was to analyse the systematic reviews conducted to inform the 2013 Australian Dietary Guidelines according to dietary exposure. The secondary aim was to analyse the reviews by health outcome, and design of included studies. To identify the systematic reviews, the dietary guidelines report was used as a starting point and relevant references were retrieved. The evidence report contained the data used in this analysis. Descriptive statistics were used to analyse reviews according to exposure, outcome, and design of included studies. A total of 143 systematic reviews were included in this analysis. Foods were the most common exposure (86·7 % of reviews), followed by nutrients (10·5 %) and dietary patterns (2·8 %). Chronic disease morbidity and/or mortality was the most common outcome (80·4 %), followed by chronic disease risk factors (19·6 %). Most reviews included evidence from cohort or nested case–control studies (92·3 %), many included evidence from case–control studies (61·5 %) and some included evidence from randomised controlled trials (28·7 %). These results reflect the research questions that were asked, the systematic review methods that were used, and the evidence that was available. In developing future iterations of the Australian Dietary Guidelines, there is an opportunity to review the latest evidence from dietary patterns research.

Due to differences in the circulation of influenza viruses, distribution and antigenic drift of A subtypes and B lineages, and susceptibility to infection in the population, the incidence of symptomatic influenza infection can vary widely between seasons and age-groups. Our goal was to estimate the symptomatic infection incidence in the Netherlands for the six seasons 2011/2012 through 2016/2017, using Bayesian evidence synthesis methodology to combine season-specific sentinel surveillance data on influenza-like illness (ILI), virus detections in sampled ILI cases and data on healthcare-seeking behaviour. Estimated age-aggregated incidence was 6.5 per 1000 persons (95% uncertainty interval (UI): 4.7–9.0) for season 2011/2012, 36.7 (95% UI: 31.2–42.8) for 2012/2013, 9.1 (95% UI: 6.3–12.9) for 2013/2014, 41.1 (95% UI: 35.0–47.7) for 2014/2015, 39.4 (95% UI: 33.4–46.1) for 2015/2016 and 27.8 (95% UI: 22.7–33.7) for season 2016/2017. Incidence varied substantially between age-groups (highest for the age-group <5 years: 23 to 47/1000, but relatively low for 65+ years: 2 to 34/1000 over the six seasons). Integration of all relevant data sources within an evidence synthesis framework has allowed the estimation – with appropriately quantified uncertainty – of the incidence of symptomatic influenza virus infection. These estimates provide valuable insight into the variation in influenza epidemics across seasons, by virus subtype and lineage, and between age-groups.

Objectives: The evaluation of public health interventions poses some challenges. As a consequence, health technology assessment (HTA) methods for public health interventions (PHI) have to be adapted. This study aimed to summarize the available guidance on methods for HTA of PHI.

Methods: We systematically searched for methodological guidance on HTA of PHIs. Our focus was on research synthesis methods to evaluate effectiveness. Relevant information was synthesized narratively in a standardized way.

Results: Only four guidance documents were identified specifically for HTAs of PHI. The approaches used for HTAs of PHIs are broader and more flexible than those for medical interventions. For this reason, there is a tendency to identify the intervention components and context factors that influence the effectiveness and transferability of an intervention rather than to assess its effectiveness in general. The details in the guidance vary without justification. Unjustified heterogeneity between the different guidance approaches is most pronounced for quality assessment, assessment of applicability, and methods to integrate qualitative and quantitative evidence. Descriptions for the assessment of integrity, heterogeneity, sustainability, context factors, and applicability are often vague.

Conclusions: The heterogeneity in approaches indicates that there is currently no consensus on methods to deal with the challenges of the PHI evaluations. A possible explanation for this may be that the methods are not sufficiently developed, and advantages and disadvantages of a certain method in relation to the research question (e.g., broad/focused) have not yet been sufficiently evaluated.

In this paper, we provide an introduction to systematic reviews and discuss the process for conducting systematic reviews in animal health, animal welfare, and food safety. The research synthesis need that can be addressed by a systematic review is discussed. The use of systematic reviews to address questions about intervention effects, etiology, diagnostic tests evaluation and disease burden are discussed. The steps included in a systematic review are described.

Information on the incidence of Chlamydia trachomatis (CT) is essential for models of the effectiveness and cost-effectiveness of screening programmes. We developed two independent estimates of CT incidence in women in England: one based on an incidence study, with estimates ‘recalibrated’ to the general population using data on setting-specific relative risks, and allowing for clearance and re-infection during follow-up; the second based on UK prevalence data, and information on the duration of CT infection. The consistency of independent sources of data on incidence, prevalence and duration, validates estimates of these parameters. Pooled estimates of the annual incidence rate in women aged 16–24 and 16–44 years for 2001–2005 using all these data were 0·05 [95% credible interval (CrI) 0·035–0·071] and 0·021 (95% CrI 0·015–0·028), respectively. Although, the estimates apply to England, similar methods could be used in other countries. The methods could be extended to dynamic models to synthesize, and assess the consistency of data on contact and transmission rates.