National public health response to an outbreak of toxigenic Corynebacterium diphtheriae among asylum seekers in England, 2022: a descriptive epidemiological study.

BACKGROUND: In July, 2022, an increase in diphtheria cases caused by toxigenic Corynebacterium diphtheriae (C diphtheriae) was reported among asylum seekers arriving by small boats to England. Rising case numbers presented challenges for case and contact management in initial reception centres, prompting changes to national guidance and implementation of population-based control measures. This study aimed to describe the outbreak of toxigenic C diphtheriae among asylum seekers arriving by small boats to England during 2022 by use of national surveillance data. METHODS: We undertook a descriptive epidemiological analysis of cases of toxigenic C diphtheriae among asylum seekers arriving by small boats to England during 2022, incorporating genomic sequencing data, antibiotic susceptibility testing results, and epidemiological data obtained through the UK Health Security Agency's national enhanced surveillance programme. Health Protection Teams conducted risk assessments, and operational data (including details regarding offer and uptake of antibiotics and vaccinations) were obtained from National Health Service partners supporting the intervention programme. FINDINGS: In 2022, C diphtheriae isolates from 86 asylum seekers arriving by small boats were submitted to the National Reference Laboratory for confirmation and testing. Toxigenic C diphtheriae was confirmed for 72 (84%) cases and one individual with typical diphtheritic lesions but from whom no C diphtheriae was isolated from clinical swabs was also included as a probable case, resulting in 73 cases of diphtheria. 71 (97%) were male, 39 (53%) were younger than 18 years, and 36 (49%) presented with cutaneous diphtheria. The prevalence of diphtheria was highest among Afghans (1·3%) compared with all other nationalities (<0·1%). Local antibiotic susceptibility testing identified six cases with a macrolide resistant strain. INTERPRETATION: The increase in diphtheria coincided with a high volume of asylum seekers arriving by small boats to England during 2022, and subsequently increased clinical awareness of the disease among this population. Long-term disruption to vaccination programmes in origin countries along with barriers to accessing health care along migrant routes puts asylum seekers arriving by small boats at risk of disease. With arrivals expected to continue in 2023, the UK Health Security Agency has recommended continuation of population-based control measures in England until October, 2023, subject to ongoing review. FUNDING: The UK Health Security Agency.

Effectiveness of one dose of MVA-BN smallpox vaccine against mpox in England using the case-coverage method: an observational study.

BACKGROUND: The UK experienced a national outbreak of mpox (formerly known as monkeypox) disease that started in May, 2022, as did many other countries worldwide, with case numbers rising rapidly, mainly among gay, bisexual, and other men who have sex with men (GBMSM). To control the outbreak, Modified Vaccinia Ankara-Bavaria Nordic (MVA-BN), an attenuated smallpox vaccine, was offered to at-risk GBMSM. We aimed to assess the effectiveness of a single MVA-BN dose against symptomatic mpox disease in at-risk GBMSM. METHODS: In this case-coverage study, mpox cases in England were sent questionnaires collecting information on demographics, vaccination history, symptoms, and sexual orientation. Returned questionnaires were linked to laboratory data and a public health case management system (HP Zone) to obtain additional information on symptom onset and specimen date. Cases with a rash onset date (or alternative proxy) between July 4 and Oct 9, 2022, were included. Females, heterosexual men, and those with missing vaccination information were excluded. Vaccine effectiveness was calculated using the case-coverage method in which vaccine coverage among cases is compared with coverage in the eligible population, estimated from doses given to GBMSM and the estimated size of at-risk GBMSM. Sensitivity analyses included an increase and decrease of 20% differences in the estimated high-risk GBMSM population size. FINDINGS: By Nov 3, 2022, 1102 people had responded to questionnaires, of which 739 were excluded (52 females or self-declared male heterosexuals, 590 with an index date outside of the study period, and 97 missing a vaccination date). 363 cases were included in the analyses. Vaccine uptake among eligible GBMSM increased steadily from July, 2022, reaching 47% by Oct 9, 2022. Of the 363 confirmed cases, eight cases either did occur or were likely to have occurred at least 14 days after vaccination, 32 within 0-13 days after vaccination, and the rest were unvaccinated. The estimated vaccine effectiveness against symptomatic mpox at least 14 days after a single dose was 78% (95% CI 54 to 89) ranging from 71 to 85 in sensitivity analyses. Vaccine effectiveness within 0-13 days after vaccination was -4% (95% CI -50 to 29). INTERPRETATION: A single MVA-BN dose was highly protective against symptomatic mpox disease among at-risk GBMSM, making it a useful tool for mpox outbreak control when rapid protection is needed. For cases in which numbers at highest risk of infection exceed vaccine supply, there might be benefit in prioritising delivery of first doses. FUNDING: UK Health Security Agency.

Transmission of SARS-CoV-2 by children to contacts in schools and households: a prospective cohort and environmental sampling study in London.

BACKGROUND: Assessing transmission of SARS-CoV-2 by children in schools is of crucial importance to inform public health action. We assessed frequency of acquisition of SARS-CoV-2 by contacts of pupils with COVID-19 in schools and households, and quantified SARS-CoV-2 shedding into air and onto fomites in both settings. METHODS: We did a prospective cohort and environmental sampling study in London, UK in eight schools. Schools reporting new cases of SARS-CoV-2 infection to local health protection teams were invited to take part if a child index case had been attending school in the 48 h before a positive SARS-CoV-2 PCR test. At the time of the study, PCR testing was available to symptomatic individuals only. Children aged 2-14 years (extended to <18 years in November, 2020) with a new nose or throat swab SARS-CoV-2 positive PCR from an accredited laboratory were included. Incidents involving exposure to at least one index pupil with COVID-19 were identified (the prevailing variants were original, α, and δ). Weekly PCR testing for SARS-CoV-2 was done on immediate classroom contacts (the so-called bubble), non-bubble school contacts, and household contacts of index pupils. Testing was supported by genome sequencing and on-surface and air samples from school and home environments. FINDINGS: Between October, 2020, and July, 2021 from the eight schools included, secondary transmission of SARS-CoV-2 was not detected in 28 bubble contacts, representing ten bubble classes (participation rate 8·8% [IQR 4·6-15·3]). Across eight non-bubble classes, 3 (2%) of 62 pupils tested positive, but these were unrelated to the original index case (participation rate 22·5% [9·7-32·3]). All three were asymptomatic and tested positive in one setting on the same day. In contrast, secondary transmission to previously negative household contacts from infected index pupils was found in six (17%) of 35 household contacts rising to 13 (28%) of 47 household contacts when considering all potential infections in household contacts. Environmental contamination with SARS-CoV-2 was rare in schools: fomite SARS-CoV-2 was identified in four (2%) of 189 samples in bubble classrooms, two (2%) of 127 samples in non-bubble classrooms, and five (4%) of 130 samples in washrooms. This contrasted with fomites in households, where SARS-CoV-2 was identified in 60 (24%) of 248 bedroom samples, 66 (27%) of 241 communal room samples, and 21 (11%) 188 bathroom samples. Air sampling identified SARS-CoV-2 RNA in just one (2%) of 68 of school air samples, compared with 21 (25%) of 85 air samples taken in homes. INTERPRETATION: There was no evidence of large-scale SARS-CoV-2 transmission in schools with precautions in place. Low levels of environmental contamination in schools are consistent with low transmission frequency and suggest adequate cleaning and ventilation in schools during the period of study. The high frequency of secondary transmission in households associated with evident viral shedding throughout the home suggests a need to improve advice to households with infection in children to prevent onward community spread. The data suggest that SARS-CoV-2 transmission from children in any setting is very likely to occur when precautions are reduced. FUNDING: UK Research and Innovation and UK Department of Health and Social Care, National Institute for Health and Care Research.

Frequency of transmission, asymptomatic shedding, and airborne spread of Streptococcus pyogenes in schoolchildren exposed to scarlet fever: a prospective, longitudinal, multicohort, molecular epidemiological, contact-tracing study in England, UK.

BACKGROUND: Despite recommendations regarding prompt treatment of cases and enhanced hygiene measures, scarlet fever outbreaks increased in England between 2014 and 2018. We aimed to assess the effects of standard interventions on transmission of Streptococcus pyogenes to classroom contacts, households, and classroom environments to inform future guidance. METHODS: We did a prospective, longitudinal, multicohort, molecular epidemiological, contact-tracing study in six settings across five schools in Greater London, UK. Schools and nurseries were eligible to participate if they had reported two cases of scarlet fever within 10 days of each other among children aged 2-8 years from the same class, with the most recent case arising in the preceding 48 h. We cultured throat swabs from children with scarlet fever, classroom contacts, and household contacts at four timepoints. We also cultured hand swabs and cough plates from all cases in years 1 and 2 of the study, and from classroom contacts in year 2. Surface swabs from toys and other fomites in classrooms were cultured in year 1, and settle plates from classrooms were collected in year 2. Any sample with S pyogenes detected was recorded as positive and underwent emm genotyping and genome sequencing to compare with the outbreak strain. FINDINGS: Six classes, comprising 12 cases of scarlet fever, 17 household contacts, and 278 classroom contacts were recruited between March 1 and May 31, 2018 (year 1), and between March 1 and May 31, 2019 (year 2). Asymptomatic throat carriage of the outbreak strains increased from 11 (10%) of 115 swabbed children in week 1, to 34 (27%) of 126 in week 2, to 26 (24%) of 108 in week 3, and then five (14%) of 35 in week 4. Compared with carriage of outbreak S pyogenes strains, colonisation with non-outbreak and non-genotyped S pyogenes strains occurred in two (2%) of 115 swabbed children in week 1, five (4%) of 126 in week 2, six (6%) of 108 in week 3, and in none of the 35 children in week 4 (median carriage for entire study 2·8% [IQR 0·0-6·6]). Genome sequencing showed clonality of outbreak isolates within each of six classes, confirming that recent transmission accounted for high carriage. When transmissibility was tested, one (9%) of 11 asymptomatic carriers of emm4 and five (36%) of 14 asymptomatic carriers of emm3.93 had a positive cough plate. The outbreak strain was identified in only one (2%) of 60 surface swabs taken from three classrooms; however, in the two classrooms with settle plates placed in elevated locations, two (17%) of 12 and six (50%) of 12 settle plates yielded the outbreak strain. INTERPRETATION: Transmission of S pyogenes in schools is intense and might occur before or despite reported treatment of cases, underlining a need for rapid case management. Despite guideline adherence, heavy shedding of S pyogenes by few classroom contacts might perpetuate outbreaks, and airborne transmission has a plausible role in its spread. These findings highlight the need for research to improve understanding and to assess effectiveness of interventions to reduce airborne transmission of S pyogenes. FUNDING: Action Medical Research, UK Research Innovation, and National Institute for Health Research.

Clinical management and impact of scarlet fever in the modern era: findings from a cross-sectional study of cases in London, 2018-2019.

OBJECTIVES: In response to increasing incidence of scarlet fever and wider outbreaks of group A streptococcal infections in London, we aimed to characterise the epidemiology, symptoms, management and consequences of scarlet fever, and to identify factors associated with delayed diagnosis. DESIGN AND SETTING: Cross-sectional community-based study of children with scarlet fever notified to London's three Health Protection Teams, 2018-2019. PARTICIPANTS: From 2575 directly invited notified cases plus invitations via parental networks at 410 schools/nurseries with notified outbreaks of confirmed/probable scarlet fever, we received 477 responses (19% of those directly invited), of which 412 met the case definition. Median age was 4 years (range <1 to 16), 48% were female, and 70% were of white ethnicity. OUTCOME MEASURES: Preplanned measures included quantitative description of case demographics, symptoms, care-seeking, and clinical, social, and economic impact on cases and households. After survey completion, secondary analyses of factors associated with delayed diagnosis (by logistic regression) and consequences of delayed diagnosis (by Cox's regression), and qualitative analysis of free text comments were added. RESULTS: Rash was reported for 89% of cases, but followed onset of other symptoms for 71%, with a median 1-day delay. Pattern of onset varied with age: sore throat was more common at onset among children 5 years and older (OR3.1, 95% CI 1.9 to 5.0). At first consultation, for 28%, scarlet fever was not considered: in these cases, symptoms were frequently attributed to viral infection (60%, 64/106). Delay in diagnosis beyond first consultation occurred more frequently among children aged 5+ who presented with sore throat (OR 2.8 vs 5+without sore throat; 95% CI 1.3 to 5.8). Cases with delayed diagnosis took, on average, 1 day longer to return to baseline activities. CONCLUSIONS: Scarlet fever may be initially overlooked, especially among older children presenting with sore throat. Raising awareness among carers and practitioners may aid identification and timely treatment.

Household transmission of invasive group A Streptococcus infections in England: a population-based study, 2009, 2011 to 2013.

Invasive group A streptococcal infection has a 15% case fatality rate and a risk of secondary transmission. This retrospective study used two national data sources from England; enhanced surveillance (2009) and a case management system (2011-2013) to identify clusters of severe group A streptococcal disease. Twenty-four household pairs were identified. The median onset interval between cases was 2 days (range 0-28) with simultaneous onset in eight pairs. The attack rate during the 30 days after first exposure to a primary case was 4,520 per 100,000 person-years at risk (95% confidence interval (CI): 2,900-6,730) a 1,940 (95% CI: 1,240-2,880) fold elevation over the background incidence. The theoretical number needed to treat to prevent one secondary case using antibiotic prophylaxis was 271 overall (95% CI: 194-454), 50 for mother-neonate pairs (95% CI: 27-393) and 82 for couples aged 75 years and over (95% CI: 46-417). While a dramatically increased risk of infection was noted in all household contacts, increased risk was greatest for mother-neonate pairs and couples aged 75 and over, suggesting targeted prophylaxis could be considered. Offering prophylaxis is challenging due to the short time interval between cases emphasising the importance of immediate notification and assessment of contacts.

Preventing secondary cases of invasive meningococcal capsular group B (MenB) disease using a recently-licensed, multi-component, protein-based vaccine (Bexsero(®)).

OBJECTIVES: To assess the potential use of a protein-based meningococcal group B (MenB) vaccine (Bexsero(®)) in addition to antibiotic chemoprophylaxis for preventing secondary cases. METHODS: Published studies on the risk of secondary meningococcal infections were used to estimate the numbers needed to vaccinate (NNV) with Bexsero(®) to prevent a secondary case in household and educational settings. RESULTS: Most secondary cases occur within a few days of diagnosis in the index case. Unlike conjugate vaccines, early protection offered after a single dose of Bexsero(®) is likely to be low, particularly in young children, who are at higher risk of secondary infection. NNV was dependent on predicted meningococcal strain coverage, estimated onset of protection after one Bexsero(®) dose and estimated vaccine efficacy. Even in the most favourable scenario where we assume the vaccine is administered within 4 days of the index case and prevents 90% of cases occurring after 14 days, the NNV for household contacts was >1000. NNV in educational settings was much higher. CONCLUSIONS: The estimated NNV should be taken into account when deciding policy to recommend Bexsero(®) for close contacts of single cases in household or educational settings. Bexsero(®) may have a protective role in clusters and outbreaks.

Guidelines for prevention and control of group A streptococcal infection in acute healthcare and maternity settings in the UK.

Hospital outbreaks of group A streptococcal (GAS) infection can be devastating and occasionally result in the death of previously well patients. Approximately one in ten cases of severe GAS infection is healthcare-associated. This guidance, produced by a multidisciplinary working group, provides an evidence-based systematic approach to the investigation of single cases or outbreaks of healthcare-associated GAS infection in acute care or maternity settings. The guideline recommends that all cases of GAS infection potentially acquired in hospital or through contact with healthcare or maternity services should be investigated. Healthcare workers, the environment, and other patients are possible sources of transmission. Screening of epidemiologically linked healthcare workers should be considered for healthcare-associated cases of GAS infection where no alternative source is readily identified. Communal facilities, such as baths, bidets and showers, should be cleaned and decontaminated between all patients especially on delivery suites, post-natal wards and other high risk areas. Continuous surveillance is required to identify outbreaks which arise over long periods of time. GAS isolates from in-patients, peri-partum patients, neonates, and post-operative wounds should be saved for six months to facilitate outbreak investigation. These guidelines do not cover diagnosis and treatment of GAS infection which should be discussed with an infection specialist.

Panton-Valentine Leukocidin associated Staphylococcus aureus infections in London, England: clinical and socio-demographic characterisation, management, burden of disease and associated costs.

Routine notification of Staphylococcus aureus producing the Panton-Valentine Leucocidin toxin (PVL-SA) to the North East & Central London Health Protection Unit, a communicable disease control unit covering a population of 2.8 million, identified 115 cases in 2009-2010, including 99 skin and soft tissue infections (SSTIs), 15 severe infections and one asymptomatic colonisation. Most cases occurred in children and young adults, unequally distributed geographically and socio-economically. The majority of infections were community acquired and 60% were caused by methicillin resistant strains. Overall, 27% of cases had previous SSTIs, and 32% had contacts with SSTIs suggestive of PVL-SA albeit these were not confirmed microbiologically. This suggests that characteristics of PVL-SA infection in cases and their families are not recognised as such leading to delay in diagnosis and low case ascertainment. A lack of governance around effective case management may also be contributing to the burden of disease. Further studies are recommended to evaluate key aspects of PVL-SA management including the effectiveness of decolonisation in the elimination of carriage and prevention of local spread.

National survey to assess current practices in the diagnosis and management of young people with dementia.

BACKGROUND: The Royal College of Psychiatrists has recommended that old age psychiatrists may be best placed to take responsibility for service provision for younger people with dementia. There are concerns however, that if referral between specialists, particularly neurologists and old age psychiatrists, is incomplete, patients may be under investigated or inappropriately followed up. OBJECTIVES: We have assessed the current level of referral between these specialists, how each investigates their patients and details of follow up care. METHOD: We conducted a postal survey of all consultant neurologists and consultant old age psychiatrists in the UK with an overall response rate of 64%. RESULTS AND CONCLUSIONS: The ideal of full collaboration between old age psychiatrists and neurologists is not achieved. Young patients may be under investigated if managed solely by an old age psychiatrist and may not receive adequate follow up services if managed solely by a neurologist.