Quantifying and Adjusting for Confounding From Health-Seeking Behavior and Health Care Access in Observational Research.

Background: Health-seeking behavior and health care access (HSB/HCA) are recognized confounders in many observational studies but are not directly measurable in electronic health records. We used proxy markers of HSB/HCA to quantify and adjust for confounding in observational studies of influenza and COVID-19 vaccine effectiveness (VE).

Methods: This cohort study used primary care data prelinked to secondary care and death data in England.

Identifying markers of health-seeking behaviour and healthcare access in UK electronic health records.

Objective: To assess the feasibility of identifying markers of health-seeking behaviour and healthcare access in UK electronic health records (EHR), for identifying populations at risk of poor health outcomes and adjusting for confounding in epidemiological studies.

Design: Cross-sectional observational study using the Clinical Practice Research Datalink Aurum prelinked to Hospital Episode Statistics.

Setting: Individual-level routine clinical data from 13 million patients across general practices (GPs) and secondary data in England.

A New Validated Approach for Identifying Childhood Immunizations in Electronic Health Records in the United Kingdom.

Background: Routinely collected electronic health records (EHR) offer a valuable opportunity to carry out research on immunization uptake, effectiveness, and safety, using large and representative samples of the population. In contrast to other drugs, vaccines do not require electronic prescription in many settings, which may lead to ambiguous coding of vaccination status and timing.

Methodology: We propose a comprehensive algorithm to identifying childhood immunizations in routinely collected EHR.

Timeliness of childhood vaccination in England: A population-based cohort study.

Introduction: Vaccine surveillance for children in England focuses on coverage at ages 1, 2, and 5 years. Previous studies exploring vaccine timeliness have used different arbitrary categories to define whether vaccines were received 'late' or 'on time'. This paper aims to provide more detailed and holistic information on timing and patterns of vaccine uptake across the childhood immunisation schedule in England.

Bias assessment of a test-negative design study of COVID-19 vaccine effectiveness used in national policymaking.

National test-negative-case-control (TNCC) studies are used to monitor COVID-19 vaccine effectiveness in the UK. A questionnaire was sent to participants from the first published TNCC COVID-19 vaccine effectiveness study conducted by the UK Health Security Agency, to assess for potential biases and changes in behaviour related to vaccination. The original study included symptomatic adults aged ≥70 years testing for COVID-19 between 08/12/2020 and 21/02/2021.

Safety of COVID-19 vaccination and acute neurological events: A self-controlled case series in England using the OpenSAFELY platform.

Introduction: We investigated the potential association of COVID-19 vaccination with three acute neurological events: Guillain-Barré syndrome (GBS), transverse myelitis and Bell's palsy.

Methods: With the approval of NHS England we analysed primary care data from >17 million patients in England linked to emergency care, hospital admission and mortality records in the OpenSAFELY platform. Separately for each vaccine brand, we used a self-controlled case series design to estimate the incidence rate ratio for each outcome in the period following vaccination (4-42 days for GBS, 4-28 days for transverse myelitis and Bell's palsy) compared to a within-person baseline, using conditional Poisson regression.

Social determinants of pertussis and influenza vaccine uptake in pregnancy: a national cohort study in England using electronic health records.

Objective: To examine the social determinants of influenza and pertussis vaccine uptake among pregnant women in England.

Design: Nationwide population-based cohort study.

Setting: The study used anonymised primary care data from the Clinical Practice Research Datalink and linked Hospital Episode Statistics secondary care data.

UK prevalence of underlying conditions which increase the risk of severe COVID-19 disease: a point prevalence study using electronic health records.

Background: Characterising the size and distribution of the population at risk of severe COVID-19 is vital for effective policy and planning. Older age, and underlying health conditions, are associated with higher risk of death from COVID-19. This study aimed to describe the population at risk of severe COVID-19 due to underlying health conditions across the United Kingdom.

Parents' and guardians' views on the acceptability of a future COVID-19 vaccine: A multi-methods study in England.

Background: The availability of a COVID-19 vaccine has been heralded as key to controlling the COVID-19 pandemic. COVID-19 vaccination programme success will rely on public willingness to be vaccinated.

Methods: We used a multi-methods approach - involving an online cross-sectional survey and semi-structured interviews - to investigate parents' and guardians' views on the acceptability of a future COVID-19 vaccine.

Early impact of the coronavirus disease (COVID-19) pandemic and physical distancing measures on routine childhood vaccinations in England, January to April 2020.

Using electronic health records, we assessed the early impact of coronavirus disease (COVID-19) on routine childhood vaccination in England by 26 April 2020. Measles-mumps-rubella vaccination counts fell from February 2020, and in the 3 weeks after introduction of physical distancing measures were 19.8% lower (95% confidence interval: -20.

Safety of inadvertent administration of live zoster vaccine to immunosuppressed individuals in a UK-based observational cohort analysis.

Objectives: To investigate the safety of live attenuated varicella zoster vaccination when administered to immunosuppressed individuals.

Design: Prospective observational cohort study.

Setting: The study used anonymised data from the Clinical Practice Research Datalink (CPRD), comprising a representative sample of routinely collected primary care data in England between 2013 and 2017 and and linked Hospital Episode Statistics data.

Assessment of Effectiveness of Seasonal Influenza Vaccination During Pregnancy in Preventing Influenza Infection in Infants in England, 2013-2014 and 2014-2015.

Maternal influenza vaccination is increasingly recognized to protect infants from influenza infection in their first 6 months. We used the screening method to estimate vaccine effectiveness (VE) against laboratory-confirmed influenza in infants in England, using newly available uptake data from the Clinical Practice Research Datalink pregnancy register, matched on week of birth and region and adjusted for ethnicity. We found VE of 66% (95% confidence interval [CI], 18%-84%) in the 2013-2014 season and 50% (95% CI, 11%-72%) in 2014-2015, with similar VE against influenza-related hospitalization.

Effectiveness of oral rotavirus vaccination in England against rotavirus-confirmed and all-cause acute gastroenteritis.

Background: The monovalent oral rotavirus vaccine Rotarix® was introduced into the UK infant immunisation programme in 2013. We estimated vaccine effectiveness (VE) in the first two years of the programme.

Methods: We used a test-negative case-control design and enhanced national surveillance data for 1869 vaccine-eligible children tested for rotavirus infection to obtain adjusted odds ratios and VE against laboratory-confirmed rotavirus infections.

The risk of non-specific hospitalised infections following MMR vaccination given with and without inactivated vaccines in the second year of life. Comparative self-controlled case-series study in England.

Observational cohort studies in high-income settings have suggested that vaccination order may affect children's subsequent risk of a heterologous infection, with live vaccines reducing and inactivated vaccines (given on their own or with a live vaccine), increasing the risk. We used the self-controlled case-series method, which automatically controls for the individual level confounding to which such cohort studies are prone, to test this hypothesis. We compared the relative incidence (RI) of infections post-vaccination in two calendar periods in England; in Period 1 (September 2002-August 2006) live measles, mumps, rubella (MMR) vaccine was given on its own and in Period 2 (September 2006-April 2010) inactivated vaccines (7-valent pneumococcal conjugate vaccine (PCV7) and sometimes the combined Haemophilus influenzae type b/meningococcal group C vaccine (Hib-MenC)) were given concomitantly with MMR.

Zoster vaccination inequalities: A population based cohort study using linked data from the UK Clinical Practice Research Datalink.

Objective: To quantify inequalities in zoster vaccine uptake by determining its association with socio-demographic factors: age, gender, ethnicity, immigration status, deprivation (at Lower-layer Super Output Area-level), care home residence and living arrangements.

Method: This population-based cohort study utilised anonymised primary care electronic health records from England (Clinical Practice Research Datalink) linked to deprivation and hospitalisation data. Data from 35,333 individuals from 277 general practices in England and eligible for zoster vaccination during the two-year period (2013-2015) after vaccine introduction were analysed.

Exome array analysis of adverse reactions to fluoropyrimidine-based therapy for gastrointestinal cancer.

Fluoropyrimidines, including 5-fluororacil (5FU) and its pro-drug Capecitabine, are the common treatment for colorectal, breast, neck and head cancers-either as monotherapy or in combination therapy. Adverse reactions (ADRs) to the treatment are common and often result in treatment discontinuation or dose reduction. Factors contributing to ADRs, including genetic variation, are poorly characterized.

Effectiveness of herpes zoster vaccination in an older United Kingdom population.

Background: Vaccination against herpes zoster was introduced in the United Kingdom in 2013 for individuals aged 70 years, with a phased catch-up campaign for 71-79 year olds. Vaccine introduction has resulted in a marked fall in incident herpes zoster and in post-herpetic neuralgia (PHN), but formal evaluation of vaccine effectiveness is needed.

Methods: In a population-based cohort study of older individuals born between 1933 and 1946, we used linked UK anonymised primary care health records for the first three years of the vaccination programme (01/09/2013-31/08/2016) and multivariable Poisson regression to obtain incidence rates and vaccine effectiveness (VE) against zoster and PHN.

Identifying social factors amongst older individuals in linked electronic health records: An assessment in a population based study.

Identification and quantification of health inequities amongst specific social groups is a pre-requisite for designing targeted healthcare interventions. This study investigated the recording of social factors in linked electronic health records (EHR) of individuals aged ≥65 years, to assess the potential of these data to identify the social determinants of disease burden and uptake of healthcare interventions. Methodology was developed for ascertaining social factors recorded on or before a pre-specified index date (01/01/2013) using primary care data from Clinical Practice Research Datalink (CPRD) linked to hospitalisation and deprivation data in a cross-sectional study.

Impact of the national rotavirus vaccination programme on acute gastroenteritis in England and associated costs averted.

Background: Introduction of infant oral rotavirus vaccination in the UK in July 2013 has resulted in decreased hospitalisations and Emergency Department (ED) visits for acute gastroenteritis (AGE), for both adults and children. We investigated reductions in AGE incidence seen in primary care in the two years after vaccine introduction, and estimated the healthcare costs averted across healthcare settings in the first year of the vaccination programme.

Methods: We used primary care data from the Clinical Practice Research Datalink and age-stratified time-series analyses to derive adjusted incidence rate ratios (IRR) for AGE in the first two years of the post-vaccination era (July 2013-April 2015) compared to the pre-vaccination era (July 2008-June 2013).