Emergency department attendances and inpatient admissions due to mpox infection, England, 2022.

OBJECTIVES: In 2022, a global outbreak of mpox was reported. In the UK, it predominantly affected gay, bisexual and men who have sex with men (GBMSM). The study objectives were to describe the impact of the mpox outbreak on healthcare service usage in England in 2022, particularly emergency department (ED) attendance, inpatient admission and a number of bed days. Additionally, we wanted to explore whether pre-exposure prophylaxis (PrEP) usage, as a marker of condomless anal intercourse, which increases the risk of sexually transmitted infections associated with compromised skin integrity, was associated with higher ED attendance or hospital attendance. METHODS: Data on adult males with laboratory-confirmed mpox were linked with hospital records and described. Using routinely collected data and self-reported exposure data (including PrEP usage) from surveillance questionnaires, multinomial regression was used to estimate adjusted relative risk ratios (aRRRs) with 95% CIs for ED attendance and hospital admission compared with those not admitted. RESULTS: Among 3542 adult males with mpox during May to December 2022, 544 (15.4%) attended ED and 202 (5.7%) were admitted to the hospital. London had the most cases (2393, 68.7%), ED attendances (391, 71.9%) and hospital admissions (121, 59.9%). In multinomial regression, we found strong evidence that compared with people living with HIV, the aRRR for hospital admissions was higher in those not using PrEP (6.9 (95% CI 2.3 to 20.6) vs 4.9 (95% CI 1.7 to 14.1)). The aRRR for ED attendance was 0.63 (95% CI 0.36 to 1.1) for those not using PrEP versus 0.49 (95% CI 0.31 to 0.79). CONCLUSIONS: This outbreak had a considerable impact on health services, particularly in high-incidence areas. Commissioners of sexual and healthcare services should review plans for healthcare provision for similar sexually transmitted infection or novel outbreaks among GBMSM or naïve populations in the future. Further studies are needed to confirm and identify reasons for the higher likelihood of hospital admission seen for GBMSM without HIV infection.

Laboratory Evaluation of a Quaternary Ammonium Compound-Based Antimicrobial Coating Used in Public Transport during the COVID-19 Pandemic.

The virucidal activity of the Zoono Z71 Microbe Shield surface sanitizer and protectant, a quaternary ammonium compound (QAC)-based antimicrobial coating that was used by the United Kingdom rail industry during the COVID-19 pandemic, was evaluated, using the bacteriophage ɸ6 as a surrogate for SARS-CoV-2. Immediately after application and in the absence of interfering substances, the product effectively reduced (>3 log10) the viability of ɸ6 on some materials that are typically used in rail carriages (stainless steel, high-pressure laminate, plastic). If, after the application of the product, these surfaces remained undisturbed, the antimicrobial coating retained its efficacy for at least 28 days. However, efficacy depended on the material being coated. The product provided inconsistent results when applied to glass surfaces and was ineffective (i.e., achieved <3 log10 reduction) when applied to a train arm rest that was made of Terluran 22. Regardless of the material that was coated or the time since application, the presence of organic debris (fetal bovine serum) significantly reduced the viricidal activity of the coating. Wiping the surface with a wetted cloth after the deposition of organic debris was not sufficient to restore efficacy. We conclude that the product is likely to be of limited effectiveness in a busy, multiuser environment, such as public transport. IMPORTANCE This study evaluated the performance of a commercially available antimicrobial coating that was used by the transport industry in the United Kingdom during the COVID-19 pandemic. While the product was effective against ɸ6, the efficacy of the coating depended upon the material to which it was applied. Similarly, and regardless of the surface material, the presence of organic debris severely impaired viricidal activity, and efficacy could not be recovered through wiping (cleaning) the surface. This highlights the importance of including relevant materials and conditions when evaluating antimicrobial coatings in the laboratory. Further efforts are required to identify suitable infection prevention and control practices for the transport industry.

Association between socioeconomic deprivation and incidence of infectious intestinal disease by pathogen and linked transmission route: An ecological analysis in the UK.

Infectious intestinal disease (IID) studies conducted at different levels of the surveillance pyramid have found heterogeneity in the association of socioeconomic deprivation with illness. The aim of this study was to analyse the association between socioeconomic deprivation and incidence of IID by certain gastrointestinal pathogens reported to UKHSA. Data were extracted from 2015 to 2018 for Salmonella, Campylobacter, Shigella, Giardia species, and norovirus. Rates were calculated per 100,000 person-years by the index of multiple deprivation quintile, and an ecological analysis was conducted using univariant and multvariable regression models for each pathogen. Incidence of Campylobacter, and Giardia species decreased with increasing deprivation. Conversely, the incidence of norovirus, non-typhoidal Salmonella, Salmonella typhi/paratyphi, Shigella species increased with increasing deprivation. Multivariable analysis results showed that higher deprivation was significantly associated with higher odds of higher number of cases for Shigella flexneri, norovirus and S. typhi/paratyphi. Infections most associated with deprivation were those transmitted by person-to-person spread, and least associated were those transmitted by zoonotic contamination of the environment. Person-to-person transmission can be contained by implementing policies targeting over-crowding and poor hygiene. This approach is likely to be the most effective solution for the reduction of IID.

Factors associated with return of home oral fluid kits by suspected cases of measles, cohort study, London and South East of England, 2016-2018.

A testing rate for measles above 80% is required by the WHO European Region Measles Elimination strategy to verify elimination. To comply with this rate, we explored factors associated with the return of oral fluid kits (OFK) by suspected measles cases. We described the cases and conducted a mixed-effects analysis to assess the relationship between socio-demographic and public health management characteristics and the likelihood of returning an OFK to the reference laboratory. Of 3,929 cases who were sent a postal OFK, 2,513 (67%) returned the kit. Adjusting for confounding, registration with a general practitioner (GP) (aOR:1.48, 95%CI:1.23-1.76) and living in a less deprived area (aOR:1.35, 95%CI:1.04-1.74) were associated with an increased likelihood of returning the OFK. The odds of returning the OFK also increased if the HPT contacted the parents/guardians of all cases prior to sending the kit and confirmed their address (aOR:2.01, 95%CI:1.17-3.42). Cases notified by a hospital (aOR:1.94, 95%CI:1.31-2.87) or GP (aOR:1.52; 95%CI:1.06-2.16) also had higher odds of returning the OFK. HPTs may want to consider these factors when managing suspected cases of measles since this may help in increasing the testing rates to the WHO-recommended level.

The effect of community water fluoridation on dental caries in children and young people in England: an ecological study.

BACKGROUND: The protective effect of community water fluoridation (CWF) against dental caries may be modified by secular changes in health behaviour. We aimed to determine the contemporary association between fluoride in public water supplies (PWS) and dental caries indicators and inequalities in England. METHODS: We estimated exposure to CWF and PWS fluoride concentrations from national monitoring data, using Geographic Information Systems and water supply boundaries, categorizing mean period exposure into <0.1, 0.1-<0.2, 0.2-<0.4, 0.4-<0.7 and ≥0.7 mg/l. We used area-level health outcome and confounder data in multivariable regression models to determine the association between fluoride and caries outcomes and calculated preventive fractions using these coefficients. RESULTS: The odds of caries and of severe caries in 5-year-olds fell with increasing fluoride concentration in all SES quintiles (P < 0.001 to P = 0.003). There was a negative trend between increasing fluoride concentration and dental extractions (P < 0.001). Compared to PWS with <0.2 mg/l, CWF prevented 17% (95% confidence interval (CI): 5-27%) to 28% (95% CI: 24-32%) of caries (high-low SES) and 56% (95% CI: 25-74%) of dental extractions. The association between fluoride concentration and caries prevalence/severity varied by socioeconomic status (SES) (P < 0.001). CONCLUSIONS: Exposure to fluoride in PWS appears highly protective against dental caries and reduces oral health inequalities.

Comparison of Surface Persistence of SARS-CoV-2 Alpha and Delta Variants on Stainless Steel at 4°C and 24°C.

Most studies on surface persistence of SARS-CoV-2 have been conducted at temperatures between 20°C and 30°C. There is limited data on the survival of SARS-CoV-2 at low temperatures. In this study, the stability of SARS-CoV-2 Alpha and Delta variants on stainless steel was investigated at two temperatures (4°C and 24°C). The results show that both variants decayed more rapidly at 24°C compared with 4°C. At 24°C, Alpha and Delta variants showed reductions of 0.33 log10 and 1.02 log10, respectively, within the first 2.5 h. However, at 4°C, Alpha variant showed a reduction of 0.16 log10 within the first 2.5 h while no reduction was observed with Delta variant. After remaining in situ for 24 h at 24°C, log10 reductions of 2.66 (Alpha) and 3.11 (Delta) were observed. No viable Alpha and Delta variant was recovered after 48 h and 72 h, respectively. After 24 h in a refrigerated environment (4°C) log10 reductions of 1.16 (Alpha) and 0.95 (Delta) were observed. Under these experimental conditions, both viruses survived on stainless steel for at least 1 week. No viable Alpha and Delta variant was recovered after 10 days. These findings support the potential for increased fomite transmission of SARS-CoV-2 during winter months in colder regions worldwide and in some industrial sectors. IMPORTANCE Human transmission is believed to occur primarily through direct transfer of infectious droplets or aerosols. However, fomite transmission through contact with contaminated surfaces may also play an important role. This study provides novel evidence comparing the stability of Alpha and Delta variants on stainless steel surfaces at 4°C and 24°C. At 4°C both variants were found to be still detectable for up to 7 days. At 24°C Delta variant could be recovered over 2 days compared with Alpha variant which could not be recovered after 2 days. This has implications for fomite transmission interventions for people living and working in cold environments.

Social risk factors for SARS-CoV-2 acquisition in university students: cross sectional survey.

The objectives of this study were to define risk factors for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in University of Cambridge (UoC) students during a period of increased incidence in October and November 2020. The study design was a survey.Routine public health surveillance identified an increase in the numbers of UoC students with confirmed SARS-CoV-2 positivity in the 10 days after a national lockdown was announced in the UK on 5th November 2020. Cases were identified both through symptom-triggered testing and a universal asymptomatic testing programme. An online questionnaire was sent to all UoC students on 25 November to investigate risk factors for testing positive in the period after 30th October 2020. This asked about symptoms, SARS-CoV-2 test results, aspects of university life, and attendance at social events in the week prior to lockdown. Univariate and multivariable analyses were undertaken evaluating potential risk factors for SARS-CoV-2 positivity.Among 3980 students responding to the questionnaire, 99 (2.5%) reported testing SARS-CoV-2 positive in the period studied; 28 (28%) were asymptomatic. We found strong independent associations with SARS-CoV-2 positivity and attendance at two social settings in the City of Cambridge (adjusted odds ratio favouring disease 13.0 (95% CI 6.2-26.9) and 14.2 (95% CI 2.9-70)), with weaker evidence of association with three further social settings. By contrast, we did not observe strong independent associations between disease risk and accommodation type or attendance at a range of activities associated with the university curriculum.To conclude attendance at social settings can facilitate widespread SARS-CoV-2 transmission in university students. Constraint of transmission in higher education settings needs to emphasise risks outside university premises, as well as a COVID-safe environment within university premises.

'As safe as houses; the risk of childhood lead exposure from housing in England and implications for public health'.

BACKGROUND AND AIM: Exposure to lead can harm a child's health, including damage to the nervous system, delayed growth, hearing loss, and many other adverse health effects, as well as implications for social, economic, educational and social well-being. Lead exposure in children is still a concern and cases require public health management to find the exposure source and interrupt the exposure pathway. Housing characteristics can indicate the presence of lead-contaminated paint and leaded water supply pipes. We aimed to explore the relationship between housing characteristics and elevated blood lead concentration (BLC) in children in England. METHODS: We used a retrospective cohort design and included all cases of lead exposure in children reported to the UK Health Security Agency between 2014 and 2020 via surveillance. A case was a child aged under 16 years, resident in England, BLC of ≥ 0.48 µmol/L (10 µg/dL) and referred for public health management. We collected case demographic details and housing characteristics (age and type). We explored associations between elevated BLC and risk factors, using generalised linear mixed effects models and compared cases' housing type to that expected nationally. RESULTS: Two hundred and sixty-six out of 290 cases met the case definition. There was no difference in BLCs between genders, age groups, deprivation, and housing type. After adjusting for reporting source, housing age and type, cases residing in housing built pre-1976 had a BLC of 0.32 (95%CI 0.02, 0.63) µmols/L (6.63 (95%CI 0.42, 13.0) µg/dL) higher than cases living in housing built after this time. Cases were 1.68 times more likely to be living in terraced housing (housing adjoined to one another) than other children and less likely to live in apartments and detached properties. CONCLUSION: This study suggests an association between housing characteristics and BLC in children. Housing age and type may act as a proxy for lead exposure risk through exposure to leaded paint, lead water pipes, and lead contaminated dust from indoor and outdoor sources. Public health action should consider targeting families more at risk in older housing by raising awareness of the potential presence of lead pipes and paint. Interventions should include working with wider stakeholders including other housing and environmental professionals, the private sector, as well as parents and carers.

Comparing public knowledge around value of hand and respiratory hygiene, vaccination, and pre- and post-national COVID-19 lockdown in England.

OBJECTIVES: The COVID-19 pandemic spotlighted the importance of infection prevention and control (IPC) measures. Existing literature focuses on healthcare professionals, whereas this article explores changes in public knowledge of IPC, where knowledge is comparably sparse. STUDY DESIGN: National surveys were conducted before (March 2020) and after (March 2021) the COVID-19 lockdown across England. METHODS: A telephone survey of 1676 adults (2021) and a face-to-face survey of 2202 adults (2020) across England were conducted. Key demographics were representative of the population. Weighted logistic regression with composite Wald P-values was used to investigate knowledge change from 2020 to 2021. RESULTS: Compared with 2020, significantly more respondents correctly stated that infections can spread by shaking hands (86% post vs 79% pre; P < .001) and that microbes are transferred through touching surfaces (90% vs 80%; P < .001). More knew that hand gel is effective at removing microbes if water and soap are unavailable (94% vs 92%; P = .015); that when you cough, you may infect other people near you in a room (90% vs 80%; P < .001). Knowledge that vaccination protects others from infection also increased (63% post vs 50% pre; P < .001). There was also significant increase in those confident in their answers. CONCLUSION: Knowledge of IPC measures was higher in 2021 than before the pandemic. Future public health hygiene campaigns should capitalise on this and emphasise that continuing hygiene behaviours, and vaccination can help prevent acquisition and illnesses with other non-COVID-19 infections, thus reducing the strain on the national health service.

Factors associated with delayed presentation to healthcare facilities for Lassa fever cases, Nigeria 2019: a retrospective cohort study.

BACKGROUND: Large outbreaks of Lassa fever (LF) occur annually in Nigeria. The case fatality rate among hospitalised cases is ~ 20%. The antiviral drug ribavirin along with supportive care and rehydration are the recommended treatments but must be administered early (within 6 days of symptom onset) for optimal results. We aimed to identify factors associated with late presentation of LF cases to a healthcare facility to inform interventions. METHODS: We undertook a retrospective cohort study of all laboratory confirmed LF cases reported in Nigeria from December 2018 to April 2019. We performed descriptive epidemiology and a univariate Cox proportional-hazards regression analysis to investigate the effect of clinical (symptom severity), epidemiological (age, sex, education, occupation, residential State) and exposure (travel, attendance at funeral, exposure to rodents or confirmed case) factors on time to presentation. RESULTS: Of 389 cases, median presentation time was 6 days (IQR 4-10 days), with 53% attending within 6 days. There were no differences in presentation times by sex but differences were noted by age-group; 60+ year-olds had the longest delays while 13-17 year-olds had the shortest. By sex and age, there were differences seen among the younger ages, with 0-4-year-old females presenting earlier than males (4 days and 73% vs. 10 days and 30%). For 5-12 and 13-17 year-olds, males presented sooner than females (males: 5 days, 65% and 3 days, 85% vs. females: 6 days, 50% and 5 days, 61%, respectively). Presentation times differed across occupations 4.5-9 days and 20-60%, transporters (people who drive informal public transport vehicles) had the longest delays. Other data were limited (41-95% missing). However, the Cox regression showed no factors were statistically associated with longer presentation time. CONCLUSIONS: Whilst we observed important differences in presentation delays across factors, our sample size was insufficient to show any statistically significant differences that might exist. However, almost half of cases presented after 6 days of onset, highlighting the need for more accurate and complete surveillance data to determine if there is a systemic or specific cause for delays, so to inform, monitor and evaluate public health strategies and improve outcomes.

Risk behaviours of homeless people who inject drugs during an outbreak of hepatitis C, Northern Ireland, 2016-2017.

From July to August 2016, 4 homeless people who injected drugs (PWID) with acute or recent hepatitis C virus (HCV) infection were reported in Belfast. A multidisciplinary team including public health, homeless and addiction services undertook an investigation to identify risk behaviours and interrupt transmission chains. Recent HCV cases were defined as negative test within the previous year, or reported injecting for less than 1 year; acute cases had tested negative within the previous 6 months. Contacts in the injecting networks of cases were identified for testing. We undertook a cross-sectional survey using structured questionnaires to elicit risk behaviours for PWID and compare behaviours between self-reported hepatitis C positive and negative subjects. During the outbreak investigation until December 2017, 156 PWID were tested and 45 (29%) cases identified, including 7 (16%) recent and 13 (29%) acute infections. 68 PWID, including 12 cases, were interviewed. All respondents reported using heroin, with 76% injecting once or more daily. Sharing was reported for spoons (58%) and filters (53%), but also needles (27%) and syringes (29%). Hepatitis C positive individuals had higher odds to be injecting in public toilets (AOR 17, 95% CI 0.71-400, P < .05) when compared with hepatitis C negative individuals. Hepatitis C positive individuals were more likely to inject in public spaces, but all respondents indicated concerning risk behaviours. We recommend active surveillance with ongoing testing, expanding existing harm reduction programmes and access to bespoke services.

Substantial prevalence of enteroparasites Cryptosporidium spp., Giardia duodenalis and Blastocystis sp. in asymptomatic schoolchildren in Madrid, Spain, November 2017 to June 2018.

BackgroundProtozoan enteroparasites Cryptosporidium species and Giardia duodenalis are major contributors to the burden of gastrointestinal illness in children globally, whereas the stramenopile Blastocystis species has been associated with irritable bowel syndrome and skin disorders.AimTo investigate the carriage of these parasites in voluntary asymptomatic schoolchildren (4‒14 years) in 12 different primary and secondary schools in Leganés (Madrid, Spain).MethodsIn a prospective cross-sectional study, stool samples and epidemiological questionnaires on demographics and potential risk factors were collected from participating schoolchildren. Detection of enteric parasites was conducted by PCR-based methods and confirmed by sequence analysis. We calculated prevalence and odds ratios (OR) with logistic regression.ResultsStool samples and questionnaires were provided by 1,359 schoolchildren from 12 schools. The individual prevalence for any parasite was 28%; Blastocystis sp.: 13%; G. duodenalis: 18%; Cryptosporidium spp.: 1%. Two schoolchildren were infected with all three species and 53 with two species. Multivariable risk factor analysis using logistic regression models indicated that an existing infection with one parasite increased the odds for an additional infection with another parasite. The odds of Blastocystis sp. carriage increased up to the age of 10 years and being female increased the odds of Cryptosporidium spp. infection. Washing vegetables before preparing a meal was protective for Blastocystis sp. infection.ConclusionWe detected a larger than expected proportion of asymptomatic cases in the participanting schoolchildren. Further investigation of asymptomatic children should be considered. Good hygiene measures should be encouraged for individuals of all ages to protect from protozoal infections.

Influenza-associated mortality in hospital care: a retrospective cohort study of risk factors and impact of oseltamivir in an English teaching hospital, 2016 to 2017.

BackgroundEvidence of an oseltamivir treatment effect on influenza A(H3N2) virus infections in hospitalised patients is incomplete.AimsThis cohort study aimed to evaluate risk factors for death among PCR-confirmed hospitalised cases of seasonal influenza A(H3N2) of all ages and the impact of oseltamivir.MethodsParticipants included all 332 PCR-confirmed influenza A(H3N2) cases diagnosed between 30 August 2016 and 17 March 2017 in an English university teaching Hospital. Oseltamivir treatment effect on odds of inpatient death was assessed by backward stepwise multivariable logistic regression analysis.ResultsThe odds of death were reduced by two thirds (odds ratio (OR): 0.32; 95% confidence interval (CI): 0.11-0.93), in inpatients treated with a standard course of oseltamivir 75 mg two times daily for 5 days - compared with those untreated with oseltamivir, after adjustment for age, sex, current excess alcohol intake, receipt of 2016/17 seasonal influenza vaccine, serum haemoglobin and hospital vs community attribution of acquisition of influenza.ConclusionsOseltamivir treatment given according to National Institutes of Clinical Excellence (NICE); United States Centres for Disease Control and Prevention (CDC); Infectious Diseases Society of America (IDSA) and World Health Organization (WHO) guidelines was shown to be effective in reducing the odds of mortality in inpatients with PCR-confirmed seasonal influenza A(H3N2) after adjustment in a busy routine English hospital setting. Our results highlight the importance of hospitals complying with relevant guidelines for prompt seasonal influenza PCR testing and ensuring standard oseltamivir treatment to all PCR-confirmed cases of seasonal influenza.

Effect of general practice characteristics and antibiotic prescribing on Escherichia coli antibiotic non-susceptibility in the West Midlands region of England: a 4 year ecological study.

Objectives: To assess the effect of general practice characteristics and antibiotic prescribing on the number of non-susceptible Escherichia coli isolated from urine specimens submitted from community settings, we undertook an ecological study of the general practice population in the West Midlands. Methods: Descriptive analysis and multilevel modelling of temporal trends in antibiotic prescribing and non-susceptibility of E. coli urine isolates to a range of antibiotics prescribed in the community over a 4 year period. Results: Nine of the 16 antibiotic prescribing/non-susceptibility combinations demonstrated a significant statistical linear correlation with non-susceptibility either for prescribing in a quarter or for prescribing within the previous 12 months. The magnitude of the effect varied, from a 0.3% increase in the odds of non-susceptibility to ampicillin/amoxicillin (when prescribing ampicillin/amoxicillin) to a 6.3% increase in the odds of non-susceptibility to nitrofurantoin (when prescribing nitrofurantoin) for an increase of 50 DDDs per 1000 practice population within a quarter (equivalent to ∼10 courses of antibiotics). In all 16 models, single-handed general practices were shown to have a significant association with increased numbers of non-susceptible E. coli urine isolates (adjusted ORs 1.083-1.657). Increased prescribing of ampicillin/amoxicillin in winter periods was associated with increased non-susceptibility of E. coli isolated from urine specimens. Conclusions: Small increases in antibiotic prescribing in individual general practices reduce the number of susceptible bacteria in the practice population. To maintain the effectiveness of available treatment, antibiotic stewardship should be encouraged and supported within each practice.

Operational burden of implementing Salmonella Enteritidis and Typhimurium cluster detection using whole genome sequencing surveillance data in England: a retrospective assessment.

Since April 2014 all presumptive Salmonella isolates received by Public Health England (PHE) have been characterised using whole genome sequencing (WGS) and the genomic data generated used to identify clusters of infection. To inform the implementation and development of a national gastrointestinal infection surveillance system based on WGS we have retrospectively identified genetically related clusters of Salmonella Enteritidis and Salmonella Typhimurium infection over a one year period and determined the distribution of these clusters by PHE operational levels. Using a constrained WGS cluster definition based on single nucleotide polymorphism distance, case frequency and temporal spread we demonstrate that the majority of clusters spread to multiple PHE operational levels. The greatest investigative burden is on national level staff investigating small, geographically dispersed clusters. We also demonstrate that WGS identifies long-running, slowly developing clusters that may previously have remained undetected. This analysis also indicates likely increased workload for local health protection teams and will require an operational strategy to balance limited human resources with the public health importance of investigating small, geographically contained clusters of highly related cases. While there are operational challenges to its implementation, integrated cluster detection based on WGS from local to international level will provide further improvements in the identification of, response to and control of clusters of Salmonella spp. with public health significance.

Use of an ingredient-based analysis to investigate a national outbreak of Escherichia coli O157, United Kingdom, July 2016.

Public Health England was alerted to a national outbreak of Shiga toxin-producing Escherichia coli O157 PT34 in July 2016. Early investigations suggested that the likely source was a salad item consumed outside of the home. A number of cases reported consuming meals at a staff canteen (Venue A) and a garden café (Venue B). Both venues shared a common salad supplier. An investigation was undertaken to measure associations between salad items and illness using an 'ingredient-based analysis'. A retrospective case-control study was conducted using an online questionnaire to collect information on menu items consumed at each venue. Chefs at both venues were interviewed to identify ingredients contained within each menu item. Both venues were pooled together for multivariable analysis measuring associations at the ingredient level. Among 203 responses, 24 cases were identified (13 confirmed, two probable and nine possible). Case onsets ranged between 7 and 25 June 2016. Multivariable analysis identified strong evidence that only baby mixed-leaf salad from the common supplier was a vehicle of infection (adjusted odds ratio = 13.1; 95% confidence interval: 1.6-106.5). Identifying the specific salad ingredient associated with illness was made possible by using an ingredient-based analysis. We recommend the increased use of ingredient-based analyses.

A mixed-method evaluation of peer-education workshops for school-aged children to teach about antibiotics, microbes and hygiene.

Background: Delivering health topics in schools through peer education is known to be beneficial for all students involved. In this study, we have evaluated a peer-education workshop that aims to educate primary and secondary school students on hygiene, the spread of infection and antibiotics. Methods: Four schools in south-west England, in a range of localities, took part in peer-education workshops, with students completing before, after and knowledge-retention questionnaires. Mixed-effect logistic regression and mixed-effect linear regression were used to analyse the data. Data were analysed by topic, region and peer/non-peer-educator status. Qualitative interviews and focus groups with students and educators were conducted to assess changes in participants' skills, confidence and behaviour. Results: Qualitative data indicated improvements in peer-educator skills and behaviour, including confidence, team-working and communication. There was a significant improvement in knowledge for all topics covered in the intervention, although this varied by region. In the antibiotics topic, peer-educators' knowledge increased in the retention questionnaire, whereas non-peer-educators' knowledge decreased. Knowledge declined in the retention questionnaires for the other topics, although this was mostly not significant. Conclusions: This study indicates that peer education is an effective way to educate young people on important topics around health and hygiene, and to concurrently improve communication skills. Its use should be encouraged across schools to help in the implementation of the National Institute for Health and Care Excellence (NICE) guidance that recommends children are taught in an age-appropriate manner about hygiene and antibiotics.

Are pertussis cases reported too late for public health interventions? Retrospective analysis of cases in London and South East England, 2010 to 2015.

In the United Kingdom, pertussis guidance recommends prophylaxis for household contacts within 21 days of case symptom onset if the household includes a vulnerable contact. The aim of our study was to identify characteristics associated with cases reported late for public health action. We reviewed the epidemiology of cases reported in London and South East England for the period 2010 to 2015. We characterised risk factors associated with late reporting of cases and described public health actions taken on timely reported cases. From 2010 to 2015, 9,163 cases of pertussis were reported to health protection teams. Only 11% of cases were reported within 21 days of onset, limiting opportunities for secondary prevention. Timely reporting was associated with younger age groups, pregnancy, being a healthcare worker and being reported by schools or hospital clinicians. Late reporting was associated with older age groups and general practitioner or laboratory reporting. Delays, such as those due to insidious onset and late presentation to healthcare, may be unavoidable; however, delay in reporting once a patient presents can be reduced since cases can be reported before laboratory confirmation. Thus we recommend working with clinicians and laboratories to determine causes and improve early reporting to public health.

The application of a novel 'rising activity, multi-level mixed effects, indicator emphasis' (RAMMIE) method for syndromic surveillance in England.

MOTIVATION: Syndromic surveillance is the real-time collection and interpretation of data to allow the early identification of public health threats and their impact, enabling public health action. The 'rising activity, multi-level mixed effects, indicator emphasis' method was developed to provide a single robust method enabling detection of unusual activity across a wide range of syndromes, nationally and locally. RESULTS: The method is shown here to have a high sensitivity (92%) and specificity (99%) compared to previous methods, whilst halving the time taken to detect increased activity to 1.3 days. AVAILABILITY AND IMPLEMENTATION: The method has been applied successfully to syndromic surveillance systems in England providing realistic models for baseline activity and utilizing prioritization rules to ensure a manageable number of 'alarms' each day. CONTACT: roger.morbey@phe.gov.uk.

Factors influencing the time between onset of illness and specimen collection in the diagnosis of non-pregnancy associated listeriosis in England and Wales.

BACKGROUND: Listeriosis is an opportunistic bacterial infection caused by Listeria monocytogenes and predominantly affects people who are immunocompromised. Due to its severity and the population at risk, prompt clinical diagnosis and treatment of listeriosis is essential. A major step to making a clinical diagnosis is the collection of the appropriate specimen(s) for testing. This study explores factors that may influence the time between onset of illness and collection of specimen in order to inform clinical policy and develop necessary interventions. METHODS: Enhanced surveillance data on non-pregnancy associated listeriosis in England and Wales between 2004 and 2013 were collected and analysed. The difference in days between onset of symptoms and collection of specimen was calculated and factors influencing the time difference were identified using a gamma regression model. RESULTS: The median number of days between onset of symptoms and collection of specimen was two days with 27.1 % of cases reporting one day between onset of symptoms and collection of specimen and 18.8 % of cases reporting more than seven days before collection of specimen. The median number of days between onset of symptoms and collection of specimen was shorter for cases infected with Listeria monocytogenes serogroup 1/2b (one day) and cases with an underlying condition (one day) compared with cases infected with serotype 4 (two days) and cases without underlying conditions (two days). CONCLUSIONS: Our study has shown that Listeria monocytogenes serotype and the presence of an underlying condition may influence the time between onset of symptoms and collection of specimen.