School-based surveillance of acute infectious disease in children: a systematic review.

BACKGROUND: Syndromic surveillance systems are an essential component of public health surveillance and can provide timely detection of infectious disease cases and outbreaks. Whilst surveillance systems are generally embedded within healthcare, there is increasing interest in novel data sources for monitoring trends in illness, such as over-the-counter purchases, internet-based health searches and worker absenteeism. This systematic review considers the utility of school attendance registers in the surveillance of infectious disease outbreaks and occurrences amongst children. METHODS: We searched eight databases using key words related to school absence, infectious disease and syndromic surveillance. Studies were limited to those published after 1st January 1995. Studies based in nursery schools or higher education settings were excluded. Article screening was undertaken by two independent reviewers using agreed eligibility criteria. Data extraction was performed using a standardised data extraction form. Outcomes included estimates of absenteeism, correlation with existing surveillance systems and associated lead or lag times. RESULTS: Fifteen studies met the inclusion criteria, all of which were concerned with the surveillance of influenza. The specificity of absence data varied between all-cause absence, illness absence and syndrome-specific absence. Systems differed in terms of the frequency of data submissions from schools and the level of aggregation of the data. Baseline rates of illness absence varied between 2.3-3.7%, with peak absences ranging between 4.1-9.8%. Syndrome-specific absenteeism had the strongest correlation with other surveillance systems (r = 0.92), with illness absenteeism generating mixed results and all-cause absenteeism performing the least well. A similar pattern of results emerged in terms of lead and lag times, with influenza-like illness (ILI)-specific absence providing a 1-2 week lead time, compared to lag times reported for all-cause absence data and inconsistent results for illness absence data. CONCLUSION: Syndrome-specific school absences have potential utility in the syndromic surveillance of influenza, demonstrating good correlation with healthcare surveillance data and a lead time of 1-2 weeks ahead of existing surveillance measures. Further research should consider the utility of school attendance registers for conditions other than influenza, to broaden our understanding of the potential application of this data for infectious disease surveillance in children. SYSTEMATIC REVIEW REGISTRATION: PROSPERO 2019 CRD42019119737.

Understanding norovirus reporting patterns in England: a mixed model approach.

BACKGROUND: Norovirus has a higher level of under-reporting in England compared to other intestinal infectious agents such as Campylobacter or Salmonella, despite being recognised as the most common cause of gastroenteritis globally. In England, this under-reporting is a consequence of the frequently mild/self-limiting nature of the disease, combined with the passive surveillance system for infectious diseases reporting. We investigated heterogeneity in passive surveillance system in order to improve understanding of differences in reporting and laboratory testing practices of norovirus in England. METHODS: The reporting patterns of norovirus relating to age and geographical region of England were investigated using a multivariate negative binomial model. Multiple model formulations were compared, and the best performing model was determined by proper scoring rules based on one-week-ahead predictions. The reporting patterns are represented by epidemic and endemic random intercepts; values close to one and less than one imply a lower number of reports than expected in the given region and age-group. RESULTS: The best performing model highlighted atypically large and small amounts of reporting by comparison with the average in England. Endemic random intercept varied from the lowest in East Midlands in those in the under 5 year age-group (0.36, CI 0.18-0.72) to the highest in the same age group in South West (3.00, CI 1.68-5.35) and Yorkshire & the Humber (2.93, CI 1.74-4.94). Reporting by age groups showed the highest variability in young children. CONCLUSION: We identified substantial variability in reporting patterns of norovirus by age and by region of England. Our findings highlight the importance of considering uncertainty in the design of forecasting tools for norovirus, and to inform the development of more targeted risk management approaches for norovirus disease.

COVID-19 testing in outbreak-free care homes: what are the public health benefits?

BACKGROUND: COVID-19 care home outbreaks represent a significant proportion of COVID-19 morbidity and mortality in the UK. National testing initially focused on symptomatic care home residents, before extending to asymptomatic cohorts. AIM: The aim was to describe the epidemiology and transmission of COVID-19 in outbreak free care homes. METHODS: A two-point prevalence survey of COVID-19, in 34 Liverpool care homes, was performed in April and May 2020. Changes in prevalence were analysed. Associations between care home characteristics, reported infection, prevention and control interventions, and COVID-19 status were described and analysed. FINDINGS: No resident developed COVID-19 symptoms during the study. There was no significant difference between: the number of care homes containing at least one test positive resident between the first (17.6%, 95% confidence interval (CI) 6.8-34.5) and second round (14.7%, 95% CI 5.0-31.1) of testing (p>0.99); and the number of residents testing positive between the first (2.1%, 95% CI 1.2-3.4) and second round (1.0%, 95% CI 0.5-2.1) of testing (P=0.11). Care homes providing nursing care (risk ratio (RR) 7.99, 95% CI 1.1-57.3) and employing agency staff (RR 8.4, 95% CI 1.2-60.8) were more likely to contain test positive residents. Closing residents shared space was not associated with residents testing positive (RR 2.63, 95% CI 0.4-18.5). CONCLUSIONS: Asymptomatic COVID-19 care homes showed no evidence of disease transmission or development of outbreaks; suggesting that current infection prevention and control measures are effective in preventing transmission. Repeat testing at two to three weeks had limited or no public health benefits over regular daily monitoring of staff and residents for symptoms. These results should inform policies calling for regular testing of asymptomatic residents.

Risk factors associated with outbreaks of seasonal infectious disease in school settings, England, UK.

Children are important transmitters of infection. Within schools they encounter large numbers of contacts and infections can spread easily causing outbreaks. However, not all schools are affected equally. We conducted a retrospective analysis of school outbreaks to identify factors associated with the risk of gastroenteritis, influenza, rash or other outbreaks. Data on reported school outbreaks in England were obtained from Public Health England and linked with data from the Department for Education and the Office for Standards in Education, Children's Services and Skills (Ofsted). Primary and all-through schools were found to be at increased risk of outbreaks, compared with secondary schools (odds ratio (OR) 5.82, 95% confidence interval (CI) 4.50-7.58 and OR 4.66, 95% CI 3.27-6.61, respectively). School size was also significantly associated with the risk of outbreaks, with higher odds associated with larger schools. Attack rates were higher in gastroenteritis and influenza outbreaks, with lower attack rates associated with rashes (relative risk 0.17, 95% CI 0.15-0.20). Deprivation and Ofsted rating were not associated with either outbreak occurrence or the subsequent attack rate. This study identifies primary and all-through schools as key settings for health protection interventions. Public health teams need to work closely with these schools to encourage early identification and reporting of outbreaks.

Are food exposures obtained through commercial market panels representative of the general population? Implications for outbreak investigations.

Current methods of control recruitment for case-control studies can be slow (a particular issue for outbreak investigations), resource-intensive and subject to a range of biases. Commercial market panels are a potential source of rapidly recruited controls. Our study evaluated food exposure data from these panel controls, compared with an established reference dataset. Market panel data were collected from two companies using retrospective internet-based surveys; these were compared with reference data from the National Diet and Nutrition Survey (NDNS). We used logistic regression to calculate adjusted odds ratios to compare exposure to each of the 71 food items between the market panel and NDNS participants. We compared 2103 panel controls with 2696 reference participants. Adjusted for socio-demographic factors, exposure to 90% of foods was statistically different between both panels and the reference data. However, these differences were likely to be of limited practical importance for 89% of Panel A foods and 79% of Panel B foods. Market panel food exposures were comparable with reference data for common food exposures but more likely to be different for uncommon exposures. This approach should be considered for outbreak investigation, in conjunction with other considerations such as population at risk, timeliness of response and study resources.

Online market research panel members as controls in case-control studies to investigate gastrointestinal disease outbreaks: early experiences and lessons learnt from the UK.

Established methods of recruiting population controls for case-control studies to investigate gastrointestinal disease outbreaks can be time consuming, resulting in delays in identifying the source or vehicle of infection. After an initial evaluation of using online market research panel members as controls in a case-control study to investigate a Salmonella outbreak in 2013, this method was applied in four further studies in the UK between 2014 and 2016. We used data from all five studies and interviews with members of each outbreak control team and market research panel provider to review operational issues, evaluate risk of bias in this approach and consider methods to reduce confounding and bias. The investigators of each outbreak reported likely time and cost savings from using market research controls. There were systematic differences between case and control groups in some studies but no evidence that conclusions on the likely source or vehicle of infection were incorrect. Potential selection biases introduced by using this sampling frame and the low response rate are unclear. Methods that might reduce confounding and some bias should be balanced with concerns for overmatching. Further evaluation of this approach using comparisons with traditional methods and population-based exposure survey data is recommended.

Prevalence of recreational drug use reported by men who have sex with men attending sexual health clinics in Manchester, UK.

Recreational drug use (RDU) has been reported to be disproportionately higher in men who have sex with men (MSM) when compared to their heterosexual counterparts. To identify RDU, links to risky sexual practices and infections for MSM attending three sexual health clinics across Manchester, United Kingdom, a retrospective case note review was conducted using a random powered sample of service users attending three sites during 2014. Three hundred and fifty-seven case notes were reviewed across three sites. Eighteen per cent of service users reported any type of RDU. Use of at least one of the three drugs associated with chemsex (crystal methamphetamine, mephedrone, gamma hydroxybutyrate/gamma butyrolactone) was reported by 3.6%. A statistically significant difference was identified between non-drug users and any-drug users reporting: group sex (odds ratio [OR] 5.88, p = 0.013), condomless receptive anal intercourse (CRAI) (OR 2.77, p = 0.003) and condomless oral intercourse (OR 2.52, p = 0.016). A statistically significant difference was identified between chemsex-related drug user and non-drug user groups reporting: group sex (OR 13.05, p = 0.023), CRAI (OR 3.69, p = 0.029) and condomless insertive anal intercourse (OR 1.27, p = 0.039). There was also a statistically higher incidence of gonorrhoea infection in chemsex-related drug use compared with those not using drugs (p = 0.002, OR 6.88). This study identifies that substance use is common in MSM attending sexual health clinics in Manchester. High-risk sexual practices and certain sexually transmitted infections are more common in MSM reporting RDU.

Prospective use of whole genome sequencing (WGS) detected a multi-country outbreak of Salmonella Enteritidis.

Since April 2015, whole genome sequencing (WGS) has been the routine test for Salmonella identification, surveillance and outbreak investigation at the national reference laboratory in England and Wales. In May 2015, an outbreak of Salmonella Enteritidis cases was detected using WGS data and investigated. UK cases were interviewed to obtain a food history and links between suppliers were mapped to produce a food chain network for chicken eggs. The association between the food chain network and the phylogeny was explored using a network comparison approach. Food and environmental samples were taken from premises linked to cases and tested for Salmonella. Within the outbreak single nucleotide polymorphism defined cluster, 136 cases were identified in the UK and 18 in Spain. One isolate from a food containing chicken eggs was within the outbreak cluster. There was a significant association between the chicken egg food chain of UK cases and phylogeny of outbreak isolates. This is the first published Salmonella outbreak to be prospectively detected using WGS. This outbreak in the UK was linked with contemporaneous cases in Spain by WGS. We conclude that UK and Spanish cases were exposed to a common source of Salmonella-contaminated chicken eggs.

Early impact of rotavirus vaccination in a large paediatric hospital in the UK.

The impact of routine rotavirus vaccination on community-acquired (CA) and healthcare-associated (HA) rotavirus gastroenteritis (RVGE) at a large paediatric hospital, UK, was investigated over a 13-year period. A total of 1644 hospitalized children aged 0-15 years tested positive for rotavirus between July 2002 and June 2015. Interrupted time-series analysis demonstrated that, post vaccine introduction (July 2013 to June 2015), CA- and HA-RVGE hospitalizations were 83% [95% confidence interval (CI): 72-90%) and 83% (95% CI: 66-92%] lower than expected, respectively. Rotavirus vaccination has rapidly reduced the hospital rotavirus disease burden among both CA- and HA-RVGE cases.

Effect of socioeconomic deprivation on uptake of measles, mumps and rubella vaccination in Liverpool, UK over 16 years: a longitudinal ecological study.

Suboptimal uptake of the measles, mumps and rubella (MMR) vaccine by certain socioeconomic groups may have contributed to recent large measles outbreaks in the UK. We investigated whether socioeconomic deprivation was associated with MMR vaccine uptake over 16 years. Using immunization data for 72,351 children born between 1995 and 2012 in Liverpool, UK, we examined trends in vaccination uptake. Generalized linear models were constructed to examine the relative effect of socioeconomic deprivation and year of birth on MMR uptake. Uptake of MMR1 by age 24 months ranged between 82·5% in 2003 [95% confidence interval (CI) 81·2-83·7] and 93·4% in 2012 (95% CI 92·7-94·2). Uptake of MMR2 by age 60 months ranged between 65·3% (95% CI 64·4-67·4) in 2006 and 90·3% (95% CI 89·4-91·2) in 2012. In analysis adjusted for year of birth and sex, children in the most deprived communities were at significantly greater risk of not receiving MMR1 [risk ratio (RR) 1·70, 95% CI 1·45-1·99] and MMR2 (RR 1·36, 95% CI 1·22-1·52). Higher unemployment and lower household income were significantly associated with low uptake. Contrary to concerns about lower MMR uptake in affluent families, over 16 years, children from the most socioeconomically deprived communities have consistently had the lowest MMR uptake. Targeted catch-up campaigns and strategies to improve routine immunization uptake in deprived areas are needed to minimize the risk of future measles outbreaks.

Attitudes towards HIV testing via home-sampling kits ordered online (RUClear pilots 2011-12).

BACKGROUND: The burden of disease relating to undiagnosed HIV infection is significant in the UK. BHIVA (British HIV Association) recommends population screening in high prevalence areas, expanding outside traditional antenatal/GUM settings. METHODS: RUClear 2011-12 piloted expanding HIV testing outside traditional settings using home-sampling kits (dry-blood-spot testing) ordered online. Greater Manchester residents (≥age 16) could request testing via an established, online chlamydia testing service (www.ruclear.co.uk). Participant attitudes towards this new service were assessed. Qualitative methods (thematic analysis) were used to analyse free-text data submitted by participants via hard copy questionnaires issued in all testing kits. RESULTS: 79.9% (2447/3062) participants completed questionnaires, of which 30.9% (756/2447) provided free-text data. Participants overwhelmingly supported the service, valuing particularly accessibility and convenience, allowing individuals to order tests any time of day and self-sample comfortably at home; avoiding the invasive nature of venipuncture and avoiding the need for face-to-face interaction with health services. The pilot was also clinically and cost-effective. CONCLUSION: Testing via home-sampling kits ordered online (dry-blood-spot testing) was felt to be an acceptable and convenient method for accessing a HIV test. Many individuals undertook HIV testing where they would otherwise not have been tested at all. Expansion of similar services may increase the uptake of HIV testing.

Risk factors for transmission of measles during an outbreak: matched case-control study.

BACKGROUND: In 2012, an outbreak of measles occurred in Merseyside, UK with 359 confirmed cases by 30 June. Numerous cases reported visits to healthcare and social settings. AIM: To identify risk factors associated with measles transmission during the outbreak. METHODS: In April 2012, a retrospective matched case-control study was conducted. Fifty-five confirmed cases and 55 community controls, matched 1:1 for age and geography, were selected at random. Data on exposures in the two weeks before illness, including attendance at a healthcare setting, were collected via telephone interview. Univariate and multi-variate analyses were conducted and odds ratios were calculated. FINDINGS: Forty-two cases and 42 matched controls were contacted successfully. Univariate exact conditional logistic regression analysis identified that cases were more likely to have attended an emergency department, been admitted to hospital and be incompletely vaccinated (for age). Multi-variate analysis found three factors to be independently associated with measles infection: incomplete/partial vaccination for age [adjusted odds ratio (aOR) 22.1, 95% confidence interval (CI) 3.8-∞, P < 0.001], under age for routine vaccination (aOR 20.4, 95% CI 2.0-∞, P = 0.009) and hospital admission (aOR 20.2, 95% CI 1.4-∞, P = 0.025). CONCLUSIONS: Incomplete/partial vaccination, under age for routine vaccination and hospital admission were associated with measles infection. These findings highlight the importance of timely vaccination of eligible individuals, early diagnosis, timely isolation of cases, and implementation of strict infection control measures.

School-based sex education is associated with reduced risky sexual behaviour and sexually transmitted infections in young adults.

OBJECTIVE: To quantify the effectiveness of school-based sexual education on risky sexual behaviour and sexually transmitted infection (STI) acquisition in adulthood. STUDY DESIGN: Online survey of sexual attitudes and behaviours. METHODS: Students at a British university were surveyed regarding where they learnt most about sex at 14 years of age, how easy they found talking about sexual issues with their parents and age at first intercourse. The effects of these factors were modelled on risk of recent unprotected intercourse and self-reported STIs in adulthood. RESULTS: Seventy-eight of 711 (11%) students reported unprotected intercourse in the 4 weeks before the survey, and 44 (6.2%) students had ever been diagnosed with an STI. Both age at first intercourse (risk reduced by 11% per year of delayed intercourse, 95% confidence interval (CI) 3-19%) and learning about sex from lessons at school (66% reduction in risk compared with learning from one's mother, 95% CI 5-88%) were associated with reductions in risk of unprotected intercourse. Factors associated with fewer STIs were age at first intercourse (17% reduction per year of delayed intercourse, 95% CI 5-28%); and learning about sex from lessons at school (85% reduction, 95% CI 32-97%), from friends of the same age (54% reduction, CI 7-77%) and from first boy/girlfriend (85% reduction, 95% CI 35-97%) compared with learning from one's mother. CONCLUSION: School-based sexual education is effective at reducing the risk of unprotected intercourse and STIs in early adulthood. Influence from friends in adolescence may also have a positive effect on the risk of STIs in later life.

Factors affecting prevention and control of viral gastroenteritis outbreaks in care homes.

We assess the effect of key care quality indicators on viral gastroenteritis outbreaks and control in care homes using mandatory inspection data collected by a non-departmental public body. Outbreak occurrence was associated with care home size but not with overall quality or individual environmental standards. Care home size, hygiene and infection control standard scores were inversely associated with attack rate in residents, whereas delayed reporting to the local public health agency was associated with higher attack rates.

An ongoing large outbreak of measles in Merseyside, England, January to June 2012.

From 1 January to 30 June 2012, 359 confirmed and 157 probable cases of measles were reported in Merseyside, England. The most affected age groups were children under five years and young adults from 15 years of age. Most cases have been sporadic. There have been few outbreaks in nurseries; however, no outbreaks have been reported in schools. Of the cases eligible for vaccination, only 3% of the confirmed cases were fully immunised.

Costs of a limited patient notification exercise following infection control failures in a dental surgery.

In February 2008, a primary care trust in Cheshire Merseyside was notified of failures in the infection control practises of a dentist working in a large group practice. On advice from national experts, a look-back was undertaken to identify any patients infected with hepatitis followed by a notification exercise of patients who had received invasive treatment immediately afterwards. One patient with hepatitis C (HCV) was identified. Sixty patients were notified by letter and offered advice and HCV screening. The total cost of the patient notification exercise (PNE) was estimated at £85,936, equating to £1,562.47 per patient who responded to the notification (55), or £2,455.31 per patient screened (35). All results were negative. While this adds to evidence that the risk to patients in such incidents is small, failing to investigate the possibility that BBV transmission has occurred would carry public health, reputational and legal risks. Conducting a PNE in the first instance for those patients at highest risk, with the option of extending it if evidence of patient-to-patient transmission is found, ensures that the total costs of dealing appropriately with such incidents - while still substantial - are at least kept to a minimum.

Mumps outbreaks in four universities in the North West of England: prevention, detection and response.

Evidence suggests that primary and secondary vaccine failure have contributed to recent university-based mumps outbreaks. We describe the epidemiology and public health management of two such outbreaks that occurred simultaneously in two areas of the North West of England, affecting four universities, using data from routine surveillance, serology testing, and telephone interviews and electronic questionnaires. Vaccination status was obtained from GP records. Cases were predominantly first year students living in university halls of residence. Public health response involved active surveillance, isolation advice and targeted vaccination clinics. Many students lack natural immunity and mumps vaccination. Factors hindering the public health response include delayed notifications, inability to readily define the 'at risk' population, low vaccine uptake, and lack of an evidence-based, cost effective strategy.