Screening at ports of entry for Ebola Virus Disease in England-a descriptive analysis of screening assessment data, 2014-2015.

BACKGROUND: In response to the outbreak of Ebola Virus Disease (EVD) in West Africa in 2014 and evidence of spread to other countries, pre-entry screening was introduced by PHE at five major ports of entry in the England. METHODS: All passengers that entered the England via the five ports returning from Liberia, Guinea and Sierra Leonne were required to complete a Health Assessment Form and have their temperature taken. The numbers, characteristics and outcomes of these passengers were analysed. RESULTS: Between 14 October 2014 and 13 October 2015, a total of 12 648 passengers from affected countries had been screened. The majority of passengers were assessed as having no direct contact with EVD cases or high-risk events (12 069, 95.4%), although 535 (4.2%) passengers were assessed as requiring public health follow-up. In total, 39 passengers were referred directly to secondary care, although none were diagnosed with EVD. One high-risk passenger was later referred to secondary care and diagnosed with EVD. CONCLUSIONS: Collection of these screening data enabled timely monitoring of the numbers and characteristics of passengers screened for EVD, facilitated resourcing decisions and acted as a mechanism to inform passengers of the necessary public health actions.

Transmission dynamics of COVID-19 in household and community settings in the United Kingdom, January to March 2020.

BackgroundHouseholds appear to be the highest risk setting for COVID-19 transmission. Large household transmission studies in the early stages of the pandemic in Asia reported secondary attack rates ranging from 5 to 30%.AimWe aimed to investigate the transmission dynamics of COVID-19 in household and community settings in the UK.MethodsA prospective case-ascertained study design based on the World Health Organization FFX protocol was undertaken in the UK following the detection of the first case in late January 2020. Household contacts of cases were followed using enhanced surveillance forms to establish whether they developed symptoms of COVID-19, became confirmed cases and their outcomes. We estimated household secondary attack rates (SAR), serial intervals and individual and household basic reproduction numbers. The incubation period was estimated using known point source exposures that resulted in secondary cases.ResultsWe included 233 households with two or more people with 472 contacts. The overall household SAR was 37% (95% CI: 31-43%) with a mean serial interval of 4.67 days, an R0 of 1.85 and a household reproduction number of 2.33. SAR were lower in larger households and highest when the primary case was younger than 18 years. We estimated a mean incubation period of around 4.5 days.ConclusionsRates of COVID-19 household transmission were high in the UK for ages above and under 18 years, emphasising the need for preventative measures in this setting. This study highlights the importance of the FFX protocol in providing early insights on transmission dynamics.

Effectiveness of Influenza Vaccination in Preventing Hospitalization Due to Influenza in Children: A Systematic Review and Meta-analysis.

This systematic review assesses the literature for estimates of influenza vaccine effectiveness (IVE) against laboratory-confirmed influenza-associated hospitalization in children. Studies of any design to June 8, 2020, were included if the outcome was hospitalization, participants were 17 years or younger and influenza infection was laboratory-confirmed. A random-effects meta-analysis of 37 studies that used a test-negative design gave a pooled seasonal IVE against hospitalization of 53.3% (47.2-58.8) for any influenza. IVE was higher against influenza A/H1N1pdm09 (68.7%, 56.9-77.2) and lowest against influenza A/H3N2 (35.8%, 23.4-46.3). Estimates by vaccine type ranged from 44.3% (30.1-55.7) for live-attenuated influenza vaccines to 68.9% (53.6-79.2) for inactivated vaccines. IVE estimates were higher in seasons when the circulating influenza strains were antigenically matched to vaccine strains (59.3%, 48.3-68.0). Influenza vaccination gives moderate overall protection against influenza-associated hospitalization in children supporting annual vaccination. IVE varies by influenza subtype and vaccine type.

Exploiting routinely collected severe case data to monitor and predict influenza outbreaks.

BACKGROUND: Influenza remains a significant burden on health systems. Effective responses rely on the timely understanding of the magnitude and the evolution of an outbreak. For monitoring purposes, data on severe cases of influenza in England are reported weekly to Public Health England. These data are both readily available and have the potential to provide valuable information to estimate and predict the key transmission features of seasonal and pandemic influenza. METHODS: We propose an epidemic model that links the underlying unobserved influenza transmission process to data on severe influenza cases. Within a Bayesian framework, we infer retrospectively the parameters of the epidemic model for each seasonal outbreak from 2012 to 2015, including: the effective reproduction number; the initial susceptibility; the probability of admission to intensive care given infection; and the effect of school closure on transmission. The model is also implemented in real time to assess whether early forecasting of the number of admissions to intensive care is possible. RESULTS: Our model of admissions data allows reconstruction of the underlying transmission dynamics revealing: increased transmission during the season 2013/14 and a noticeable effect of the Christmas school holiday on disease spread during seasons 2012/13 and 2014/15. When information on the initial immunity of the population is available, forecasts of the number of admissions to intensive care can be substantially improved. CONCLUSION: Readily available severe case data can be effectively used to estimate epidemiological characteristics and to predict the evolution of an epidemic, crucially allowing real-time monitoring of the transmission and severity of the outbreak.

Influenza vaccination during the 2021/22 season: A data-linkage test-negative case-control study of effectiveness against influenza requiring emergency care in England and serological analysis of primary care patients.

We present England 2021/22 end-of-season adjusted vaccine effectiveness (aVE) against laboratory confirmed influenza related emergency care use in children aged 1-17 and in adults aged 50+, and serological findings in vaccinated vs unvaccinated adults by hemagglutination inhibition assay. Influenza vaccination has been routinely offered to all children aged 2-10 years and adults aged 65 years + in England. In 2021/22, the offer was extended to children to age 15 years, and adults aged 50-64 years. Influenza activity rose during the latter half of the 2021/22 season, while remaining comparatively low due to COVID-19 pandemic control measures. Influenza A(H3N2) strains predominated. A test negative design was used to estimate aVE by vaccine type. Cases and controls were identified within a sentinel laboratory surveillance system. Vaccine histories were obtained from the National Immunisation Management Service (NIMS), an influenza and COVID-19 vaccine registry. These were linked to emergency department presentations (excluding accidents) with respiratory swabbing ≤ 14 days before or ≤ 7 days after presentation. Amongst adults, 423 positive and 32,917 negative samples were eligible for inclusion, and 145 positive and 6,438 negative samples among children. Those admitted to hospital were further identified. In serology against the circulating A(H3N2) A/Bangladesh/4005/2020-like strain, 61 % of current season adult vaccinees had titres ≥ 1:40 compared to 17 % of those unvaccinated in 2020/21 or 2021/22 (p < 0.001). We found good protection from influenza vaccination against influenza requiring emergency care in children (72.7 % [95 % CI 52.7, 84.3 %]) and modest effectiveness in adults (26.1 % [95 % CI 4.5, 42.8 %]). Adult VE was higher for A(H1N1) (81 % [95 % CI 50, 93 %]) than A(H3N2) (33 % [95 % CI 6, 53 %]). Consistent protection was observable across preschool, primary and secondary school aged children. Imperfect test specificity combined with very low prevalence may have biased estimates towards null. With limited influenza circulation, the study could not determine differences by vaccine types.

WHO's Investigations and Studies, Unity Studies: A global initiative creating equitable opportunities for enhanced surveillance, operational research, capacity building, and global knowledge sharing.

The World Health Organization's Unity Studies global initiative provides a generic preparedness and readiness framework for conducting detailed investigations and epidemiological studies critical for the early and ongoing assessment of emerging respiratory pathogens of pandemic potential. During the COVID-19 pandemic, the initiative produced standardized investigation protocols and supported Member States to generate robust and comparable data to inform public health decision making. The subsequent iteration of the initiative is being implemented to develop revised and new investigation protocols, implementation toolkits and work to build a sustainable global network of sites, enabling the global community to be better prepared for the next emerging respiratory pathogen with epidemic or pandemic potential.

Rapid influenza molecular testing in secondary care and influenza surveillance in England: Any impact?

INTRODUCTION: The use of rapid molecular testing for influenza diagnosis is becoming increasingly popular. Used at the point of care or in a clinical laboratory, these tests detect influenza A and B viruses, though many do not distinguish between influenza A subtypes. The UK Severe Influenza Surveillance System (USISS) collects surveillance data on laboratory-confirmed influenza admissions to secondary care in England. This study set out to understand how rapid influenza molecular testing was being used and how it might influence the availability of subtyping data collected on influenza cases admitted to secondary care in England. METHODS: At the end of the 2017/2018 and 2018/2019 influenza seasons, a questionnaire was sent to all National Health Service Hospital Trusts in England to evaluate the use of rapid influenza testing. Surveillance data collected through USISS was analysed from 2011/2012 to 2020/2021. RESULTS: Of responding trusts, 42% (13/31) in 2017/2018 and 55% (9/17) in 2018/2019 used rapid influenza molecular tests, either alone or in combination with other testing. The majority of rapid tests used did not subtype the influenza A result, and limited follow-up testing occurred. Surveillance data showed significant proportions of influenza A hospital and intensive care unit/high dependency unit admissions without subtyping information, increasing by approximately 35% between 2012/2013 and 2020/2021. CONCLUSIONS: The use of rapid influenza molecular tests is a likely contributing factor to the large proportion of influenza A hospitalisations in England that were unsubtyped. Given their clear clinical advantages, further work must be done to reinforce these data for public health through integrated genomic surveillance.

Live-attenuated influenza vaccine effectiveness against hospitalization in children aged 2-6 years, the first three seasons of the childhood influenza vaccination program in England, 2013/14-2015/16.

INTRODUCTION: In 2013, the United Kingdom began to roll-out a universal annual influenza vaccination program for children. An important component of any new vaccination program is measuring its effectiveness. Live-attenuated influenza vaccines (LAIVs) have since shown mixed results with vaccine effectiveness (VE) varying across seasons and countries elsewhere. This study aims to assess the effectiveness of influenza vaccination in children against severe disease during the first three seasons of the LAIV program in England. METHODS: Using the screening method, LAIV vaccination coverage in children hospitalized with laboratory-confirmed influenza infection was compared with vaccination coverage in 2-6-year-olds in the general population to estimate VE in 2013/14-2015/16. RESULTS: The overall LAIV VE, adjusted for age group, week/month and geographical area, for all influenza types pooled over the three influenza seasons was 50.1% (95% confidence interval [CI] 31.2, 63.8). By age, there was evidence of protection against hospitalization from influenza vaccination in both the pre-school (2-4-year-olds) (48.1%, 95% CI 27.2, 63.1) and school-aged children (5-6-year-olds) (62.6%, 95% CI 2.6, 85.6) over the three seasons. CONCLUSION: LAIV vaccination in children provided moderate annual protection against laboratory-confirmed influenza-related hospitalization in England over the three influenza seasons. This study contributes further to the limited literature to date on influenza VE against severe disease in children.