Public perceptions and interactions with UK COVID-19 Test, Trace and Isolate policies, and implications for pandemic infectious disease modelling (preprint)

The efforts to contain SARS-CoV-2 and reduce the impact of COVID-19 have been supported by Test, Trace and Isolate (TTI) systems in many settings, including the United Kingdom. The mathematical models underlying policy decisions about TTI make assumptions about behaviour in the context of a rapidly unfolding and changeable emergency. This study investigates the reported behaviours of UK citizens in July 2021, assesses them against how a set of TTI processes are conceptualised and represented in models and then interprets the findings with modellers who have been contributing evidence to TTI policy. We report on testing practices, including the uses of and trust in different types of testing, and the challenges of testing and isolating faced by different demographic groups. The study demonstrates the potential of input from members of the public to benefit the modelling process, from guiding the choice of research questions, influencing choice of model structure, informing parameter ranges and validating or challenging assumptions, to highlighting where model assumptions are reasonable or where their poor reflection of practice might lead to uninformative results. We conclude that deeper engagement with members of the public should be integrated at regular stages of public health intervention modelling.

Low income parents’ perspectives and experiences of engaging with early years health professionals about financial challenges and income maximisation

BackgroundSince the introduction of the Child Poverty Act (2017) in Scotland, all health visitors, midwives and family nurses in Scotland are expected to screen and offer a financial advice referral to at-risk pregnant women and parents/carers of families with children under five in Scotland. The so-called ‘Financial Inclusion Pathway’ (FIP) emerged in 2019 as one of a number of strategies intended to tackle child poverty. At this early implementation stage, little is known about parents’ perspectives about the acceptability or impact of this initiative in relation to its aim.MethodsIn 2020, low income parents with young children living in Aberdeen City were invited to take part in a qualitative study that aimed to determine any challenges they might face engaging with the FIP policy in practice, and their perspectives about financial discussions with professionals that could help to increase household incomes through this approach.One-to-one semi-structured telephone interviews lasting between 30–40 minutes took place during July and August 2020. Interviews were fully transcribed and thematically analysed.ResultsTen women, ranging from ages 20–41 years. Each participant had between one and five child(ren), ranging in age from 2 to 18 years and all had one child under school-age. All lived in multiply deprived postcode areas within Aberdeen City. Three main themes emerged: i. difficulties associated with discussing financial concerns;ii. how to talk about the issue;iii. intervention utility. Within each of these three main themes, nine-sub themes were apparent, ranging from those indicating potential unintended negative consequences, as well as intervention benefits.DiscussionMost participants considered health visitors to be a potentially good source of help about financial challenges;they were less clear about midwives’ role here. However, parents’ perceptions of the problems they may face associated with disclosing financial difficulties to health professionals, is a distinct barrier to conversations that could lead to a financial advice referral. Given the levels of unclaimed benefit in the UK, this is important to note. Establishing trust and rapport, careful and sensitive enquiry, and positive framing of financial maximisation were recommended to aid discussion of financial challenges. These findings are important given the current and predicted economic impact of the COVID-19. The study is limited by its sample size and recruitment site, but provides valuable insights to inform a larger scale investigation. The study also indicates the importance of understanding health professionals’ associated views and experiences.

Responsible modelling: Unit testing for infectious disease epidemiology (preprint)

Infectious disease epidemiology is increasingly reliant on large-scale computation and inference. Models have guided health policy for epidemics including COVID-19 and Ebola and endemic diseases such as malaria and tuberculosis. Yet a single coding bug may bias results, leading to incorrect conclusions and wrong actions that could cause avoidable harm. We are ethically obliged to ensure our code is as free of error as possible. Unit testing is a coding method to avoid such bugs, but unit testing is rarely used in epidemiology. We demonstrate through simple examples how unit testing can handle the particular quirks of infectious disease models.

Dynamics of SARS-CoV-2 with Waning Immunity in the UK Population (preprint)

The dynamics of immunity are crucial to understanding the long-term patterns of the SARS-CoV-2 pandemic. While the duration and strength of immunity to SARS-CoV-2 is currently unknown, specific antibody titres to related coronaviruses SARS-CoV and MERS-CoV have been shown to wane in recovered individuals, and immunity to seasonal circulating coronaviruses is estimated to be shorter than one year. Using an age-structured, deterministic model, we explore different potential immunity dynamics using contact data from the UK population. In the scenario where immunity to SARS-CoV-2 lasts an average of three months for non-hospitalised individuals, a year for hospitalised individuals, and the effective reproduction number (Rt) after lockdown is 1.2 (our worst case scenario), we find that the secondary peak occurs in winter 2020 with a daily maximum of 409,000 infectious individuals; almost three-fold greater than in a scenario with permanent immunity. Our models suggests that longitudinal serological surveys to determine if immunity in the population is waning will be most informative when sampling takes place from the end of the lockdown until autumn 2020. After this period, the proportion of the population with antibodies to SARS-CoV-2 is expected to increase due to the secondary peak. Overall, our analysis presents considerations for policy makers on the longer term dynamics of SARS-CoV-2 in the UK and suggests that strategies designed to achieve herd immunity may lead to repeated waves of infection if immunity to re-infection is not permanent.