Rapid rise in COVID-19 among young people in England - learning for the future.

OBJECTIVES: We determined the age and sociodemographic distribution of COVID-19 cases between January and September 2020 to identify the group with the highest incidence rates at the beginning of the second wave in England. STUDY DESIGN: We undertook a retrospective cohort study design. METHODS: SARS-CoV-2 cases in England were linked with area-level socio-economic status indicators using quintiles of the Index of Multiple Deprivation (IMD). Age-specific incidence rates were stratified by IMD quintile to further assess rates by area-level socio-economic status. RESULTS: Between July and September 2020, SARS-CoV-2 incidence rates were highest amongst those aged 18-21 years, reaching rates of 213.9 (18-19 years) and 143.2 (20-21 years) per 100,000 population by week ending 21 September 2022. Stratification of incidence rates by IMD quintile evidenced that despite high rates observed in the most deprived areas of England amongst the very young and older age groups, the highest rates were observed in the most affluent areas of England amongst the 18- to 21-year-olds. CONCLUSIONS: The reversal of sociodemographic trend in COVID-19 cases in England for those aged 18-21 years at the end of the summer of 2020 and beginning of the second wave showed a novel pattern of COVID-19 risk. For other age groups, the rates remained highest for those from more deprived areas, which highlighted persisting inequalities. Combined, this demonstrates the need to reinforce awareness of COVID-19 risk for young people, particularly given the late inclusion of the 16-17 years age group for vaccination administration, as well as continued efforts to reduce the impact of COVID-19 on vulnerable populations.

Hospitalisation and mortality risk of SARS-COV-2 variant omicron sub-lineage BA.2 compared to BA.1 in England.

The Omicron variant of SARS-CoV-2 became the globally dominant variant in early 2022. A sub-lineage of the Omicron variant (BA.2) was identified in England in January 2022. Here, we investigated hospitalisation and mortality risks of COVID-19 cases with the Omicron sub-lineage BA.2 (n = 258,875) compared to BA.1 (n = 984,337) in a large cohort study in England. We estimated the risk of hospital attendance, hospital admission or death using multivariable stratified proportional hazards regression models. After adjustment for confounders, BA.2 cases had lower or similar risks of death (HR = 0.80, 95% CI 0.71-0.90), hospital admission (HR = 0.88, 95% CI 0.83-0.94) and any hospital attendance (HR = 0.98, 95% CI 0.95-1.01). These findings that the risk of severe outcomes following infection with BA.2 SARS-CoV-2 was slightly lower or equivalent to the BA.1 sub-lineage can inform public health strategies in countries where BA.2 is spreading.

Risk of hospitalisation or death in households with a case of COVID-19 in England: an analysis using the HOSTED data set.

OBJECTIVE: To determine whether household contacts of confirmed cases of COVID-19 have an increased risk of hospitalisation or death. METHODS: We used the HOSTED data set of index cases of COVID-19 in England between June and November 2020, linked to Secondary Uses Service data on hospital episodes and Office for National Statistics' mortality data. Multivariable logistic regression models of the odds of household contacts being hospitalised or dying within six weeks of an index case, adjusted for case type, age, sex and calendar month were calculated. Excess risk was determined by comparing the first six weeks after the index case with 6-12 weeks after the index case in a survival analysis framework. RESULTS: Index cases were more likely to be hospitalised or die than either secondary cases or non-cases, having adjusted for age and sex. There was an increased risk of hospitalisation for non-cases (adjusted hazard ratio (aHR) 1.10; 95% confidence interval (CI) 1.04, 1.16) and of death (aHR 1.57; 95% CI 1.14, 2.16) in the first six weeks after an index case, compared to 6-12 weeks after. CONCLUSION: Risks of hospitalisation and mortality are predictably higher in cases compared to non-cases. The short-term increase in risks for non-case contacts following diagnosis of the index case may suggest incomplete case ascertainment among contacts, although this was relatively small.

Timeliness and completeness of laboratory-based surveillance of COVID-19 cases in England.

OBJECTIVES: The aim of the study was to evaluate completeness and timeliness of the rapidly developed surveillance of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in England using patient-level data. STUDY DESIGN: This is an observational study wherein public health surveillance systems are evaluated. METHODS: Data were collected in the Public Health England's Second-Generation Surveillance System through routine laboratory reporting processes, as well as via enhanced testing in collaboration with commercial partners. Three periods were chosen to present developments in disease surveillance around the first pandemic wave in England. Completeness of valid entries for key demographic and epidemiological fields was summarised. Timeliness was assessed using recorded date intervals: from sample collection to the laboratory reporting a positive result, the positive result being received by the national surveillance system and the data being available for epidemiological analysis. RESULTS: In each period, demographic variables were more than 95% complete and enhanced ethnicity more than 85%, allowing a rich understanding of the general characteristics of COVID-19 cases in England. The proportion of cases completing all reporting stages of the national system within 3 days of when the specimen was taken increased from 69.1% in period 1 to 76.6% in period 3. In period 3, the median number of days to complete all reporting stages decreased to 2, from 3 in previous periods. Analysis of each reporting stage offers suggestive evidence that timeliness of the system has improved as reporting has become established over time. CONCLUSIONS: Timely processing of data for epidemiological use was consistent and rapid once received by the national system. Delays in timeliness were most likely to occur in the first stage of the reporting process, before laboratory input to the surveillance platform. Existing national surveillance mechanisms enhanced during the response have succeeded in providing rapid collection and reporting of case data to facilitate epidemiological monitoring and analysis and guide public health policy and strategy.

HOSTED-England's Household Transmission Evaluation Dataset: preliminary findings from a novel passive surveillance system of COVID-19.

BACKGROUND: Household transmission of SARS-CoV-2 is an important component of the community spread of the pandemic. Little is known about the factors associated with household transmission, at the level of the case, contact or household, or how these have varied over the course of the pandemic. METHODS: The Household Transmission Evaluation Dataset (HOSTED) is a passive surveillance system linking laboratory-confirmed COVID-19 cases to individuals living in the same household in England. We explored the risk of household transmission according to: age of case and contact, sex, region, deprivation, month and household composition between April and September 2020, building a multivariate model. RESULTS: In the period studied, on average, 5.5% of household contacts in England were diagnosed as cases. Household transmission was most common between adult cases and contacts of a similar age. There was some evidence of lower transmission rates to under-16s [adjusted odds ratios (aOR) 0.70, 95% confidence interval (CI) 0.66-0.74). There were clear regional differences, with higher rates of household transmission in the north of England and the Midlands. Less deprived areas had a lower risk of household transmission. After controlling for region, there was no effect of deprivation, but houses of multiple occupancy had lower rates of household transmission [aOR 0.74 (0.66-0.83)]. CONCLUSIONS: Children are less likely to acquire SARS-CoV-2 via household transmission, and consequently there was no difference in the risk of transmission in households with children. Households in which cases could isolate effectively, such as houses of multiple occupancy, had lower rates of household transmission. Policies to support the effective isolation of cases from their household contacts could lower the level of household transmission.

Six-year experience of detection and investigation of possible Middle East Respiratory Syndrome coronavirus cases, England, 2012-2018.

OBJECTIVES: Surveillance for Middle East Respiratory Syndrome (MERS) has been undertaken in the UK since September 2012. This study describes the surveillance outcomes in England from 2012 to 2018. STUDY DESIGN: This was a descriptive study using surveillance data. METHODS: Local health protection teams in England report possible MERS cases to the National Infection Service with clinical and laboratory data. RESULTS: A total of 1301 possible MERS cases were identified in the study period. Five cases were laboratory-confirmed MERS. The majority of cases had travelled to Saudi Arabia (56.7%) and United Arab Emirates (25.9%). Fifty-four percent of cases were men and 43.7% were women. The majority of cases (65.1%) were aged 45 years or older. The number of tests increased in the period after Hajj each year. Laboratory-confirmed alternative diagnoses were available for 513 (39.4%) cases; influenza was the most common virus detected (n = 255, 52.4%). CONCLUSIONS: Our study highlights the importance of differential diagnosis of influenza and other respiratory pathogens and early influenza antiviral treatment.

COVID-19: public health management of the first two confirmed cases identified in the UK.

We report key learning from the public health management of the first two confirmed cases of COVID-19 identified in the UK. The first case imported, and the second associated with probable person-to-person transmission within the UK. Contact tracing was complex and fast-moving. Potential exposures for both cases were reviewed, and 52 contacts were identified. No further confirmed COVID-19 cases have been linked epidemiologically to these two cases. As steps are made to enhance contact tracing across the UK, the lessons learned from earlier contact tracing during the country's containment phase are particularly important and timely.

Legionellosis incidents associated with spa pools, England, 2002-2018.

BACKGROUND: Spa pools (SPs) pose risks of Legionella infection for users and bystanders. METHODS: We searched the National Enhanced Legionella Surveillance System for reported SP-associated legionellosis incidents in England between 2002 and 2018 involving at least two cases. RESULTS: For seven legionellosis SP-associated incidents, six were in commercial settings such as hotels. The median number of cases per outbreak was four (range 2-115). CONCLUSION: SP-associated legionellosis incidents were mainly located in commercial settings with a wider range of cases than those recognised in previous publications, reinforcing the need for effective environmental controls for SPs in a range of settings.

Association between use of proton pump inhibitors and non-typhoidal salmonellosis identified following investigation into an outbreak of Salmonella Mikawasima in the UK, 2013.

In November 2013, national public health agencies in England and Scotland identified an increase in laboratory-confirmed Salmonella Mikawasima. The role of proton pump inhibitors (PPIs) as a risk factor for salmonellosis is unclear; we therefore captured information on PPI usage as part of our outbreak investigation. We conducted a case-control study, comparing each case with two controls. Adjusted odds ratios (aORs) and 95% confidence intervals (CIs) were estimated using multivariable logistic regression. Thirty-nine of 61 eligible cases were included in the study. The median age of cases was 45 years; 56% were female. Of these, 33% were admitted to hospital and 31% reported taking PPIs. We identified an association between PPIs and non-typhoidal salmonellosis (aOR 8·8, 95% CI 2·0-38·3). There is increasing evidence supporting the existence of an association between salmonellosis and PPIs; however, biological studies are needed to understand the effect of PPIs in the pathogenesis of Salmonella. We recommend future outbreak studies investigate PPI usage to strengthen evidence on the relevance of PPIs in Salmonella infection. These findings should be used to support the development of guidelines for patients and prescribers on the risk of gastrointestinal infection and PPI usage.

Selection of population controls for a Salmonella case-control study in the UK using a market research panel and web-survey provides time and resource savings.

Timely recruitment of population controls in infectious disease outbreak investigations is challenging. We evaluated the timeliness and cost of using a market research panel as a sampling frame for recruiting controls in a case-control study during an outbreak of Salmonella Mikawasima in the UK in 2013. We deployed a web-survey by email to targeted members of a market research panel (panel controls) in parallel to the outbreak control team interviewing randomly selected public health staff by telephone and completing paper-based questionnaires (staff controls). Recruitment and completion of exposure history web-surveys for panel controls (n = 123) took 14 h compared to 15 days for staff controls (n = 82). The average staff-time cost per questionnaire for staff controls was £13·13 compared to an invoiced cost of £3·60 per panel control. Differences in the distribution of some exposures existed between these control groups but case-control studies using each group found that illness was associated with consumption of chicken outside of the home and chicken from local butchers. Recruiting market research panel controls offers time and resource savings. More rapid investigations would enable more prompt implementation of control measures. We recommend that this method of recruiting controls is considered in future investigations and assessed further to better understand strengths and limitations.

Effectiveness of seasonal influenza vaccination during pregnancy in preventing influenza infection in infants, England, 2013/14.

In this study we used the screening method to estimate the effectiveness of seasonal influenza vaccination during pregnancy in preventing influenza virus infection and influenza-related hospitalisation in infants under six months, in England in the 2013/14 season. Seasonal influenza vaccination in pregnancy was 71% (95% CI: 24­89%) effective in preventing infant influenza virus infection and 64% (95% CI: 6­86%) effective in preventing infant influenza hospitalisation, and should be recommended in pregnancy.

Evaluation of the surveillance system for undiagnosed serious infectious illness (USII) in intensive care units, England, 2011 to 2013.

Emerging infections are a potential risk during mass gathering events due to the congregation of large numbers of international travellers. To mitigate this risk for the London 2012 Olympic and Paralympic Games, a sentinel surveillance system was developed to identify clusters of emerging infections presenting as undiagnosed serious infectious illness (USII) in intensive care units (ICUs). Following a six month pilot period, which had begun in January 2011, the surveillance was operational for a further 18 months spanning the Games. The surveillance system and reported USII cases were reviewed and evaluated after this 18 month operational period including assessment of positive predictive value (PPV), timeliness, acceptability and sensitivity of the system. Surveillance records were used to review reported cases and calculate the PPV and median reporting times of USII surveillance. Sensitivity was assessed through comparison with the pilot period. Participating clinicians completed a five-point Likert scale questionnaire about the acceptability of surveillance. Between 11 July 2011 and 10 January 2013, 34 cases were reported. Of these, 22 remained classified as USII at the time of the evaluation, none of which were still hospitalised. No clusters were identified. The 22 USII cases had no association with the Games, suggesting that they represented the background level of USII in the area covered by the surveillance. This corresponded to an annualised rate of 0.39 cases/100,000 population and a PPV of 65%. Clinicians involved in the surveillance reported high acceptability levels. The USII surveillance model could be a useful public health tool in other countries and during mass gathering events for identifying potential clusters of emerging infections.

Timeliness of electronic reporting and acceptability of public health follow-up of routine nonparatyphoidal and nontyphoidal Salmonella infections, London and South East England, 2010 to 2011.

Nonparatyphoidal and nontyphoidal Salmonella (NTS) infections are major causes of food poisoning in England. Diagnostic laboratories and clinicians have a statutory responsibility to report NTS infection cases to the Health Protection Agency via various means, with electronic reporting encouraged as the universal method. The Health Protection Agency (Public Health England since 1 April 2013) refers cases to environmental health departments for follow-up. Timeliness of reporting and adequacy of NTS infection case follow-up are key factors in the implementation of public health actions. Laboratories, health protection units, and environmental health departments in London and South East (SE) regions of England completed three surveys between December 2010 and April 2011, collecting data about the NTS infection case reporting methods and the time elapsed between symptom onset and public health actions. The median period between symptom onset and public health investigation was 25 days in London and 23 days in SE when electronic reporting was used and 12 days in London and 11 days in SE when other means of reporting were used. The most common follow-up method was a telephone questionnaire in London (53%) and a postal questionnaire in SE (52%). The telephone questionnaire had the highest response rate (98% in London; 96% in SE). Timeliness and efficiency of electronic NTS infection case reports can be improved by decreasing the electronic laboratory report period and using telephone-administered questionnaires to maximize the public health benefit when following up single cases of NTS infection.

Do enhanced sexual health services meet the needs of men who have sex with men?

Enhanced Sexual Health Services (ESHS) have the potential to widen access to sexual health services for populations in England. This study aimed to identify what provision was commissioned in ESHS for men who have sex with men (MSM). We undertook a web-based survey of Primary Care Trust (PCT) commissioners in the south-east of England, exploring what sexual health services were commissioned for MSM and comparing them with published standards. Fourteen of 17 PCTs (82%) responded. All PCTs identified at least one genitourinary (GU) medicine clinic and 13 identified at least one ESHS commissioned for their population. However no single ESHS provided the full range of essential services for MSM. Testing for Chlamydia (84.6% PCTs) and for HIV (69.2% PCTs) were most commonly provided in ESHS, while only 46% and 62% of PCTs had an ESHS commissioned to provide gonorrhoea testing and hepatitis B/syphilis serology testing respectively. Under two-thirds reported training of staff in the sexual health needs of MSM. ESHS are not commissioned to provide the full range of essential sexual health services for MSM. This needs to be addressed by improving staff training in these services and strengthening care pathways between ESHS and GU medicine clinics.

Thunderstorm asthma: an overview of the evidence base and implications for public health advice.

Thunderstorm asthma is a term used to describe an observed increase in acute bronchospasm cases following the occurrence of thunderstorms in the local vicinity. The roles of accompanying meteorological features and aeroallergens, such as pollen grains and fungal spores, have been studied in an effort to explain why thunderstorm asthma does not accompany all thunderstorms. Despite published evidence being limited and highly variable in quality due to thunderstorm asthma being a rare event, this article reviews this evidence in relation to the role of aeroallergens, meteorological features and the impact of thunderstorm asthma on health services. This review has found that several thunderstorm asthma events have had significant impacts on individuals' health and health services with a range of different aeroallergens identified. This review also makes recommendations for future public health advice relating to thunderstorm asthma on the basis of this identified evidence.