Eliciting a value set for the Swedish Capability-Adjusted Life Years instrument (CALY-SWE).

PURPOSE: Our aim was to elicit a value set for Capability-Adjusted Life Years Sweden (CALY-SWE); a capability-grounded quality of life instrument intended for use in economic evaluations of social interventions with broad consequences beyond health. METHODS: Building on methods commonly used in the quality-adjusted life years EQ-5D context, we collected time-trade off (TTO) and discrete choice experiment (DCE) data through an online survey from a general population sample of 1697 Swedish participants. We assessed data quality using a score based on the severity of inconsistencies. For generating the value set, we compared different model features, including hybrid modeling of DCE and TTO versus TTO data only, censoring of TTO answers, varying intercept, and accommodating for heteroskedasticity. We also assessed the models' DCE logit fidelity to measure agreement with potentially less-biased DCE data. To anchor the best capability state to 1 on the 0 to 1 scale, we included a multiplicative scaling factor. RESULTS: We excluded 20% of the TTO answers of participants with the largest inconsistencies to improve data quality. A hybrid model with an anchor scale and censoring was chosen to generate the value set; models with heteroskedasticity considerations or individually varying intercepts did not offer substantial improvement. The lowest capability weight was 0.114. Health, social relations, and finance and housing attributes contributed the largest capability gains, followed by occupation, security, and political and civil rights. CONCLUSION: We elicited a value set for CALY-SWE for use in economic evaluations of interventions with broad social consequences.

Occurrence and transmission potential of asymptomatic and presymptomatic SARS-CoV-2 infections: Update of a living systematic review and meta-analysis.

BACKGROUND: Debate about the level of asymptomatic Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection continues. The amount of evidence is increasing and study designs have changed over time. We updated a living systematic review to address 3 questions: (1) Among people who become infected with SARS-CoV-2, what proportion does not experience symptoms at all during their infection? (2) What is the infectiousness of asymptomatic and presymptomatic, compared with symptomatic, SARS-CoV-2 infection? (3) What proportion of SARS-CoV-2 transmission in a population is accounted for by people who are asymptomatic or presymptomatic? METHODS AND FINDINGS: The protocol was first published on 1 April 2020 and last updated on 18 June 2021. We searched PubMed, Embase, bioRxiv, and medRxiv, aggregated in a database of SARS-CoV-2 literature, most recently on 6 July 2021. Studies of people with PCR-diagnosed SARS-CoV-2, which documented symptom status at the beginning and end of follow-up, or mathematical modelling studies were included. Studies restricted to people already diagnosed, of single individuals or families, or without sufficient follow-up were excluded. One reviewer extracted data and a second verified the extraction, with disagreement resolved by discussion or a third reviewer. Risk of bias in empirical studies was assessed with a bespoke checklist and modelling studies with a published checklist. All data syntheses were done using random effects models. Review question (1): We included 130 studies. Heterogeneity was high so we did not estimate a mean proportion of asymptomatic infections overall (interquartile range (IQR) 14% to 50%, prediction interval 2% to 90%), or in 84 studies based on screening of defined populations (IQR 20% to 65%, prediction interval 4% to 94%). In 46 studies based on contact or outbreak investigations, the summary proportion asymptomatic was 19% (95% confidence interval (CI) 15% to 25%, prediction interval 2% to 70%). (2) The secondary attack rate in contacts of people with asymptomatic infection compared with symptomatic infection was 0.32 (95% CI 0.16 to 0.64, prediction interval 0.11 to 0.95, 8 studies). (3) In 13 modelling studies fit to data, the proportion of all SARS-CoV-2 transmission from presymptomatic individuals was higher than from asymptomatic individuals. Limitations of the evidence include high heterogeneity and high risks of selection and information bias in studies that were not designed to measure persistently asymptomatic infection, and limited information about variants of concern or in people who have been vaccinated. CONCLUSIONS: Based on studies published up to July 2021, most SARS-CoV-2 infections were not persistently asymptomatic, and asymptomatic infections were less infectious than symptomatic infections. Summary estimates from meta-analysis may be misleading when variability between studies is extreme and prediction intervals should be presented. Future studies should determine the asymptomatic proportion of SARS-CoV-2 infections caused by variants of concern and in people with immunity following vaccination or previous infection. Without prospective longitudinal studies with methods that minimise selection and measurement biases, further updates with the study types included in this living systematic review are unlikely to be able to provide a reliable summary estimate of the proportion of asymptomatic infections caused by SARS-CoV-2. REVIEW PROTOCOL: Open Science Framework (https://osf.io/9ewys/).

An initiative to develop capability-adjusted life years in Sweden (CALY-SWE): Selecting capabilities with a Delphi panel and developing the questionnaire.

INTRODUCTION: Capability-adjusted life years Sweden (CALY-SWE) are a new Swedish questionnaire-based measure for quality of life based on the capability approach. CALY-SWE are targeted towards use in cost-effectiveness evaluations of social welfare consequences. Here, we first motivate the measure both from a theoretical and from a Swedish policy-making perspective. Then, we outline the core principles of the measure, namely the relation to the capability approach, embedded equity considerations inspired by the fair-innings approach, and the bases for which capabilities should be considered. The aims were to 1) the most vital capabilities for individuals in Sweden, 2) to define a sufficient level of each identified capability to lead a flourishing life, and to 3) develop a complete questionnaire for the measurement of the identified capabilities. MATERIAL AND METHODS: For the selection of capabilities, we used a Delphi process with Swedish civil society representants. To inform the questionnaire development, we conducted a web survey in three versions, with each Swedish 500 participants, to assess the distribution of capabilities that resulted from the Delphi process in the Swedish population. Each version was formulated with different strictness so that less strict wordings of a capability level would apply to a larger share of participants. All versions also included questions on inequality aversion regarding financial, educational, and health capabilities. RESULTS: The Delphi process resulted in the following six capabilities: Financial situation & housing, health, social relations, occupations, security, and political & civil rights. We formulated the final phrasing for the questionnaire based on normative reasons and the distribution of capabilities in the population while taking into account inequality aversion. CONCLUSION: We developed a capability-based model for cost effectiveness economic evaluations of broader social consequences, specific to the Swedish context.

Perceived changes in capability during the COVID-19 pandemic: A Swedish cross-sectional study from June 2020.

AIMS: Measures against COVID-19 potentially impact quality of life in different ways. The capability approach by Amartya Sen with a broad and consistent framework for measuring quality of life is suited to capture the various consequences. We aimed to examine (a) whether individuals experienced change in 10 capability dimensions during the first half of 2020, (b) which dimensions were affected most, and (c) whether changes were unequally distributed in terms of gender, education, income, geography, housing, living situation and place of birth. METHODS: We assessed self-reported capability change in Sweden in 10 capability dimensions in a cross-sectional online survey among 500 participants on a five-item Likert scale. We analysed the distribution of answers by comparing the balance of positive and negative perceived changes and used mixed effects logistic regression to examine associations with background characteristics of the participants. RESULTS: Reported perceived negative changes outweighed positive changes, and a higher proportion stated negative perceived changes if they also stated having low capability in the same dimension. In the capabilities of financial situation, political resources and health, the proportions of perceived negative change were highest. Odds for perceived negative change compared to no or positive change were higher for lower incomes, living in smaller municipalities compared to living in medium-sized municipalities, being born outside Europe, living in the south of Sweden, and renting instead of owning housing. CONCLUSIONS: Self-reported negative capability change, and associated inequalities related to socioeconomic position, place of birth and regional residence should be of concern for policymakers.

Outbreaks of publications about emerging infectious diseases: the case of SARS-CoV-2 and Zika virus.

BACKGROUND: Outbreaks of infectious diseases generate outbreaks of scientific evidence. In 2016 epidemics of Zika virus emerged, and in 2020, a novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) caused a pandemic of coronavirus disease 2019 (COVID-19). We compared patterns of scientific publications for the two infections to analyse the evolution of the evidence. METHODS: We annotated publications on Zika virus and SARS-CoV-2 that we collected using living evidence databases according to study design. We used descriptive statistics to categorise and compare study designs over time. RESULTS: We found 2286 publications about Zika virus in 2016 and 21,990 about SARS-CoV-2 up to 24 May 2020, of which we analysed a random sample of 5294 (24%). For both infections, there were more epidemiological than laboratory science studies. Amongst epidemiological studies for both infections, case reports, case series and cross-sectional studies emerged first, cohort and case-control studies were published later. Trials were the last to emerge. The number of preprints was much higher for SARS-CoV-2 than for Zika virus. CONCLUSIONS: Similarities in the overall pattern of publications might be generalizable, whereas differences are compatible with differences in the characteristics of a disease. Understanding how evidence accumulates during disease outbreaks helps us understand which types of public health questions we can answer and when.

Towards capability-adjusted life years in public health and social welfare: Results from a Swedish survey on ranking capabilities.

INTRODUCTION: The aim of this study was to rank capabilities and suggest a relevant set of capabilities for the Swedish context to inform the development of capability-adjusted life years (CALYs). CALYs is a quality of life measure for policy making based on the capability approach by Amartya Sen. MATERIALS AND METHODS: A Swedish governmental review proposed the following 10 relevant capabilities: time, financial situation, mental/physical health, political resources, knowledge, living environment, occupation, social relations, security, and housing. Researchers in health-related disciplines from 5 universities ranked these capabilities from 1 to 10 (most to least important) in a web-based cross-sectional survey; 115 of 171 responses were eligible. RESULTS: Health, social relations, and financial situation were deemed most important. Stratification by gender, research field, and age group revealed few differences. We found that it was possible to rank capabilities and that health, social relations, and financial situation were ranked highest by a non-representative sample of researchers and doctoral students from health-related disciplines at five Swedish universities. CONCLUSIONS: The revealed ranking is dependent on the metric and must be further explored. The findings support continued development of CALYs for monitoring and evaluating outcomes in public health and social-welfare interventions.

Zika virus infection as a cause of congenital brain abnormalities and Guillain-Barré syndrome: A living systematic review.

Background: The Zika virus (ZIKV) caused a large outbreak in the Americas leading to the declaration of a Public Health Emergency of International Concern in February 2016. A causal relation between infection and adverse congenital outcomes such as microcephaly was declared by the World Health Organization (WHO) informed by a systematic review structured according to a framework of ten dimensions of causality, based on the work of Bradford Hill. Subsequently, the evidence has continued to accumulate, which we incorporate in regular updates of the original work, rendering it a living systematic review. Methods: We present an update of our living systematic review on the causal relation between ZIKV infection and adverse congenital outcomes and between ZIKV and GBS for four dimensions of causality: strength of association, dose-response, specificity, and consistency. We assess the evidence published between January 18, 2017 and July 1, 2019. Results: We found that the strength of association between ZIKV infection and adverse outcomes from case-control studies differs according to whether exposure to ZIKV is assessed in the mother (OR 3.8, 95% CI: 1.7-8.7, I 2=19.8%) or the foetus/infant (OR 37.4, 95% CI: 11.0-127.1, I 2=0%). In cohort studies, the risk of congenital abnormalities was 3.5 times higher after ZIKV infection (95% CI: 0.9-13.5, I 2=0%). The strength of association between ZIKV infection and GBS was higher in studies that enrolled controls from hospital (OR: 55.8, 95% CI: 17.2-181.7, I 2=0%) than in studies that enrolled controls at random from the same community or household (OR: 2.0, 95% CI: 0.8-5.4, I 2=74.6%). In case-control studies, selection of controls from hospitals could have biased results. Conclusions: The conclusions that ZIKV infection causes adverse congenital outcomes and GBS are reinforced with the evidence published between January 18, 2017 and July 1, 2019.