Now showing 1 - 10 of 21
  • Publication
    Estimation of the serial interval and proportion of pre-symptomatic transmission events of COVID-19 in Ireland using contact tracing data
    The serial interval is the period of time between the onset of symptoms in an infector and an infectee and is an important parameter which can impact on the estimation of the reproduction number. Whilst several parameters influencing infection transmission are expected to be consistent across populations, the serial interval can vary across and within populations over time. Therefore, local estimates are preferable for use in epidemiological models developed at a regional level. We used data collected as part of the national contact tracing process in Ireland to estimate the serial interval of SARS-CoV-2 infection in the Irish population, and to estimate the proportion of transmission events that occurred prior to the onset of symptoms. Results After data cleaning, the final dataset consisted of 471 infected close contacts from 471 primary cases. The median serial interval was 4 days, mean serial interval was 4.0 (95% confidence intervals 3.7, 4.3) days, whilst the 25th and 75th percentiles were 2 and 6 days respectively. We found that intervals were lower when the primary or secondary case were in the older age cohort (greater than 64 years). Simulating from an incubation period distribution from international literature, we estimated that 67% of transmission events had greater than 50% probability of occurring prior to the onset of symptoms in the infector. Conclusions Whilst our analysis was based on a large sample size, data were collected for the primary purpose of interrupting transmission chains. Similar to other studies estimating the serial interval, our analysis is restricted to transmission pairs where the infector is known with some degree of certainty. Such pairs may represent more intense contacts with infected individuals than might occur in the overall population. It is therefore possible that our analysis is biased towards shorter serial intervals than the overall population.
      165Scopus© Citations 8
  • Publication
    Moving from risk communication to food information communication and consumer engagement
    (Springer Nature, 2018-11-30) ;
    Consumers in most developed countries have greater access to safer food than ever before, yet the issue of consumer perception on the safety of the food supply, the control infrastructure and existing and new process technologies is often not positive. A series of high profile food incidents, which have been ineffectively managed by both the regulators and the industry, and where there has been a failure to be open and transparent, have sensitised a proportion of consumers to scary stories about the food supply. There has been concomitant damage to consumer confidence in (i) the safety of food, (ii) the food industry’s commitment to producing safe food and (iii) the authorities’ ability to oversee the food chain. Threats to consumers’ health and their genuine concerns have to be addressed with effective risk management and the protection of public health has to be paramount. Dealing with incorrect fears and misperceptions of risk has also to be addressed but achieving this is very difficult. The competencies of social scientists are needed to assist in gaining insights into consumer perceptions of risk, consumer behaviour and the determinants of trust. Conventional risk communication will not succeed on its own and more innovative and creative communication strategies are needed to engage with consumers using all available media channels in an open and transparent way. The digital media affords the opportunity to revolutionise engagement with consumers on food safety and nutrition-related issues.
      501Scopus© Citations 21
  • Publication
    Numbers of close contacts of individuals infected with SARS-CoV-2 and their association with government intervention strategies
    Background: Contact tracing is conducted with the primary purpose of interrupting transmission from individuals who are likely to be infectious to others. Secondary analyses of data on the numbers of close contacts of confirmed cases could also: provide an early signal of increases in contact patterns that might precede larger than expected case numbers; evaluate the impact of government interventions on the number of contacts of confirmed cases; or provide data information on contact rates between age cohorts for the purpose of epidemiological modelling. We analysed data from 140,204 close contacts of 39,861 cases in Ireland from 1st May to 1st December 2020. Results: Negative binomial regression models highlighted greater numbers of contacts within specific population demographics, after correcting for temporal associations. Separate segmented regression models of the number of cases over time and the average number of contacts per case indicated that a breakpoint indicating a rapid decrease in the number of contacts per case in October 2020 preceded a breakpoint indicating a reduction in the number of cases by 11 days. Conclusions: We found that the number of contacts per infected case was overdispersed, the mean varied considerable over time and was temporally associated with government interventions. Analysis of the reported number of contacts per individual in contact tracing data may be a useful early indicator of changes in behaviour in response to, or indeed despite, government restrictions. This study provides useful information for triangulating assumptions regarding the contact mixing rates between different age cohorts for epidemiological modelling.
      218Scopus© Citations 7
  • Publication
    Presymptomatic transmission of SARS-CoV-2 infection: a secondary analysis using published data
    Objective To estimate the proportion of presymptomatic transmission of SARS-CoV-2 infection that can occur, and the timing of transmission relative to symptom onset.Setting/design Secondary analysis of international published data.Data sources Meta-analysis of COVID-19 incubation period and a rapid review of serial interval and generation time, which are published separately.Participants Data from China, the Islamic Republic of Iran, Italy, Republic of Korea, Singapore and Vietnam from December 2019 to May 2020.Methods Simulations were generated of incubation period and of serial interval or generation time. From these, transmission times relative to symptom onset, and the proportion of presymptomatic transmission, were estimated.Outcome measures Transmission time of SARS-CoV-2 relative to symptom onset and proportion of presymptomatic transmission.Results Based on 18 serial interval/generation time estimates from 15 papers, mean transmission time relative to symptom onset ranged from −2.6 (95% CI −3.0 to –2.1) days before infector symptom onset to 1.4 (95% CI 1.0 to 1.8) days after symptom onset. The proportion of presymptomatic transmission ranged from 45.9% (95% CI 42.9% to 49.0%) to 69.1% (95% CI 66.2% to 71.9%).Conclusions There is substantial potential for presymptomatic transmission of SARS-CoV-2 across a range of different contexts. This highlights the need for rapid case detection, contact tracing and quarantine. The transmission patterns that we report reflect the combination of biological infectiousness and transmission opportunities which vary according to context.
      341Scopus© Citations 27
  • Publication
    What makes smartphone games successful in food information communication?
    China’s annual Food Safety Publicity Week in June 2019 has, for the first time, included smartphone games in its activities. Food related governmental and non-governmental organizations liaised with Alipay (Alibaba’s payment application) launching a smartphone quiz-game with an unprecedented level of public engagement with food information (i.e., food safety, nutrition, and food science and technologies): 12 million participants and 1.7 billion instances of participation within 1 week. This example demonstrates the great potential of smartphone games, and more widely, digital tools, in food-related public education. Given the extent of misinformation among the public on food safety and nutrition issues, food scientists and organizations should be empowered to embrace emerging tools, such as smartphone games, in order to positively shape public opinions. To aid in this task, this commentary article analyzes the factors behind the unprecedented success of Alipay’s smartphone quiz-game during China’s Food Safety Publicity Week.
      411Scopus© Citations 7
  • Publication
    Behavioural economics and drinking behaviour : preliminary results from an Irish college study
    (University College Dublin. Geary Institute, 2007-01-31) ; ;
    This paper examines the results of single-equation regression models of the determinants of alcohol consumption patterns among college students modelling a rich variety of covariates including gender, family and peer drinking, tenure, personality, risk perception, time preferences and age of drinking onset. The results demonstrate very weak income effects and very strong effects of personality, peer drinking (in particular closest friend), time preferences and other substance use. The task of future research is to verify these results and assess causality using more detailed methods.
  • Publication
    Consumer evaluations of processed meat products reformulated to be healthier - A conjoint analysis study
    Recent innovations in processed meats focus on healthier reformulations through reducing negative constituents and/or adding health beneficial ingredients. This study explored the influence of base meat product (ham, sausages, beef burger), salt and/or fat content (reduced or not), healthy ingredients (omega 3, vitamin E, none), and price (average or higher than average) on consumers' purchase intention and quality judgement of processed meats. A survey (n = 481) using conjoint methodology and cluster analysis was conducted. Price and base meat product were most important for consumers' purchase intention, followed by healthy ingredient and salt and/or fat content. In reformulation, consumers had a preference for ham and sausages over beef burgers, and for reduced salt and/or fat over non reduction. In relation to healthy ingredients, omega 3 was preferred over none, and vitamin E was least preferred. Healthier reformulations improved the perceived healthiness of processed meats. Cluster analyses identified three consumer segments with different product preferences.
      255Scopus© Citations 91
  • Publication
    Social capital and self-rated health in the Republic of Ireland : evidence from the European Social Survey
    (Irish Medical Association, 2007-09) ; ;
    This paper analyses the determinants of self-reported health in Ireland, conditioning self-reported health on a set of socio-economic, labour market and social capital variables. Ireland has the highest self-reported health rate in Europe, a finding backed-up by other studies. Data were derived from the 2002 and 2005 European Social survey. The full 87,915 observations from both rounds were pooled and used to estimate mean self-rated health across Europe. The Irish data were isolated, totalling 2,049 individuals for 2002 and 2,286 individuals for 2005. The 2002 data were used to analyse the determinants of subjective health state, as it had a richer array of social capital variables. The results demonstrate statistically significant effects of income on self-reported health that are robust to different statistical specifications and statistically significant though modest effects of social capital variables such as associational membership and frequency of social meeting and labour market variables such as being on a limited as opposed to permanent contract.
  • Publication
    Contact tracing during the COVID-19 outbreak: a protocol for enabling rapid learning from experiences and exploring the psychological impact on contact tracers
    Background: Given the unprecedented nature of the COVID-19 pandemic, the Irish health system required the redeployment of public sector staff and the recruitment of dedicated contact tracing staff in the effort to contain the spread of the virus. Contact tracing is crucial for effective disease control and is normally a role carried out by public health teams. Contact tracing staff are provided with rapid intensive training but are operating in a dynamic environment where processes and advice are adapting continuously. Real-time data is essential to inform strategy, coordinate interconnected processes, and respond to needs. Given that many contact tracers have been newly recruited or redeployed, they may not have significant experience in healthcare and may experience difficulties in managing the anxieties and emotional distress of members of the public. Aim: This research aims to: (i) identify emerging needs and issues and feed this information back to the Health Service Executive for updates to the COVID-19 Contact Management Programme (CMP); (ii) understand the psychological impact on contact tracers and inform the development of appropriate supports. Methods: We will use a mixed-methods approach. A brief online survey will be administered at up to three time points during 2021 to measure emotional exhaustion, anxiety, general health, and stress of contact tracing staff, identify tracing systems or processes issues, as well as issues of concern and confusion among the public. Interviews will also be conducted with a subset of participants to achieve a more in-depth understanding of these experiences. Observations may be conducted in contact tracing centres to document processes, practices, and explore any local contextual issues. Impact: Regular briefs arising from this research with data, analysis, and recommendations will aim to support the work of the CMP to identify problems and implement solutions. We will deliver regular feedback on systems issues; challenges; and the psychological well-being of contact tracing staff.
    Scopus© Citations 3  458
  • Publication
    Relative infectiousness of asymptomatic SARS-CoV-2 infected persons compared with symptomatic individuals: a rapid scoping review
    Objectives The aim of this study was to determine the relative infectiousness of asymptomatic SARS-CoV-2 infected persons compared with symptomatic individuals based on a scoping review of available literature. Design Rapid scoping review of peer-reviewed literature from 1 January to 5 December 2020 using the LitCovid database and the Cochrane library. Setting International studies on the infectiousness of individuals infected with SARS-CoV-2. Participants Studies were selected for inclusion if they defined asymptomatics as a separate cohort distinct from presymptomatics and if they provided a quantitative measure of the infectiousness of asymptomatics relative to symptomatics. Primary outcome measures PCR result (PCR studies), the rate of infection (mathematical modelling studies) and secondary attack rate (contact tracing studies) - in each case from asymptomatic in comparison with symptomatic individuals. Results There are only a limited number of published studies that report estimates of relative infectiousness of asymptomatic compared with symptomatic individuals. 12 studies were included after the screening process. Significant differences exist in the definition of infectiousness. PCR studies in general show no difference in shedding levels between symptomatic and asymptomatic individuals; however, the number of study subjects is generally limited. Two modelling studies estimate relative infectiousness to be 0.43 and 0.57, but both of these were more reflective of the infectiousness of undocumented rather than asymptomatic cases. The results from contact tracing studies include estimates of relative infectiousness of 0, but with insufficient evidence to conclude that it is significantly different from 1. Conclusions There is considerable heterogeneity in estimates of relative infectiousness highlighting the need for further investigation of this important parameter. It is not possible to provide any conclusive estimate of relative infectiousness, as the estimates from the reviewed studies varied between 0 and 1.
      286Scopus© Citations 29