Background:Despite being vaccine-preventable, hepatitis A virus (HAV) outbreaks occur among men who have sex with men (MSM). We modelled the cost-effectiveness of vaccination strategies to prevent future outbreaks. Methods:A HAV transmission model was calibrated to HAV outbreak data for MSM in England over 2016-2018, producing estimates for the basic reproduction number (R0) and immunity levels (seroprevalence) post-outbreak. For a hypothetical outbreak in 2023 (same R0 and evolving immunity), the cost-effectiveness of pre-emptive (vaccination between outbreaks among MSM attending sexual health services (SHS)) and reactive (vaccination during outbreak among MSM attending SHS and primary care) vaccination strategies were modelled. Effectiveness in quality-adjusted life-years (QALYs) and costs were estimated (2017 UK pounds) from a societal perspective (10-year time horizon; 3% discount rate). The incremental cost-effectiveness ratio (ICER) was estimated. Findings:R0 for the 2016-2018 outbreak was 3·19 (95% credibility interval (95%CrI) 2·87-3·46); seroprevalence among MSM increased to 70·4% (95%CrI 67·3-72·8%) post-outbreak. For our hypothetical HAV outbreak in 2023, pre-emptively vaccinating MSM over the preceding five-years was cost-saving (compared to no vaccination) if the yearly vaccine coverage rate among MSM attending SHS was <9·1%. Reactive vaccination was also cost-saving compared to no vaccination, but was dominated by pre-emptive vaccination if the yearly vaccination rate was >8%. If the pre-emptive yearly vaccination rate fell below this threshold, it became cost-saving to add reactive vaccination to pre-emptive vaccination. Interpretation:Although highly transmissible, existing immunity limited the recent HAV outbreak among MSM in England. Pre-emptive vaccination between outbreaks, with reactive vaccination if indicated, is the best strategy for limiting future HAV outbreaks. Funding:NIHR.

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, a, and d). 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 center dot 8% [IQR 4 center dot 6-15 center dot 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 center dot 5% [9 center dot 7-32 center dot 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 Copyright (c) 2022 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 license.

Background. Transmission of SARS-CoV-2 by children and young people in school settings has not been directly evaluated, nor the main mechanisms of transmission identified. The study set out to undertake sequential longitudinal sampling of infected children, their contacts, and the environment. Methods. Cases of COVID-19 were identified through statutory notification and matched to schools reporting cases. Cases of COVID-19 and their contacts from school and home were longitudinally sampled and tested for SARS-CoV-2. Surfaces and air in the home and school environment were also subject to longitudinal sampling and testing. Results Onward transmission of virus to immediate classroom members who participated in the study was not detected. Evidence of more widespread transmission among children remaining in school was not identified with the exception of one unexpected cluster of three asymptomatic cases in one school. Children infected with SARS-CoV-2 in this study shed viral RNA for up to 10 days from symptom onset, with levels peaking at 5-8 days. Viral RNA was identified in the environment around children who were actively shedding virus in the home, but limited contamination was identified in schools. Variant of Concern B1.1.7 was identified in later cases studied. Summary After 3 months, this small study has not found evidence to suggest COVID-19 is commonly transmitted by children within schools. A minority of infections may be subject to stochastic events that can lead to transmission. Further prospective and retrospective studies are required to identify factors associated with such events .

Introduction:Outbreaks of hepatitis A virus (HAV) have previously been described in men who have sex with men (MSM). BASHH only recommends HAV vaccination for MSM during outbreaks. A UK cluster of HAV cases was identified and, by 27/2/2017, London had 45 probable and confirmed cases in MSM. London sexual health commissioning is in flux with new arrangements imminent.Methods:For individual notified cases, Health Protection Teams (HPT) routinely assess source, offer infection control advice to the case and organise vaccination of household and sexual contacts. A London outbreak control team (OCT) comprised epidemiologists, commissioners and providers of immunisation and sexual health services, health promotion partners and communications. The OCT scoped possible additional interventions to control the outbreak.Results:The OCT recommended: Awareness raising re risk behaviour:Distribute a nationally commissioned leaflet with safer sex advice to cases and to genitourinary medicine (GUM) clinics, plus relevant content on digital platforms.Liaison with providers, commissioners: Inform GPs. Survey current practice in GUM for HAV immunisation. Vaccinate MSM opportunistically in GUM clinics (if had a new or casual partner in last 3 months).Link with existing health promotion networks: Working with gay venues, to get understanding and cooperation.Set up vaccination clinics near the popular venuesDiscussion:It is challenging to set up an immunisation programme in a large city with complex commissioning relationships at short notice. Consideration should be given to vaccination between outbreaks to reduce the proportion susceptible, or ‘outbreak ready’ plans included in sexual health commissioning arrangements.

IntroductionThe current outbreak of Hepatitis A and the recent Shigella outbreak in men who have sex with men (MSM) highlight the importance of faeco-orally transmitted organisms in this population. This may suggest that outbreaks could be predicted or prevented.MethodsWe compared the age, sex and travel history of notifications of Hepatitis A with notifications of Shigella in South London between January 2010 and November 2016. We also reviewed documentation of previous outbreaks of Hepatitis A in MSM in London.ResultsMale and female cases of Hepatitis A had similar age profiles and a similar proportion reported recent travel. In contrast, Shigella cases peaked in males aged 30–39 with no travel history. Case notes for Hepatitis A notifications since January 2013 suggested fewer than five in MSM. Although this review suggested very few cases in recent years, outbreaks of Hepatitis A among MSM in London were documented in the late 1990s and in 2003. The second outbreak was associated with strains that caused concurrent outbreaks in MSM across Europe. Public health response to these outbreaks recommended health promotion and opportunistic immunisation.DiscussionHepatitis A outbreaks occur sporadically in a transnational population of MSM. Few cases may occur between outbreaks and preventative actions may be deprioritised. However, group immunity is likely to be highest after an outbreak and then wane in the absence of immunisation, increasing the risk of another outbreak. Health promotion and immunisation may be valuable outside of outbreak contexts.

IntroductionFrom late 2016, Hepatitis A virus (HAV) infection in MSM increased in incidence in the UK and has reached outbreak status. By February 2017, 42 confirmed or suspected cases had been reported in London. An outbreak committee was convened by Public Health England and as part of this work data was gathered to ascertain current levels of vaccination and future needs in MSM attending GUM/HIV clinics.MethodsClinical leads for GUM and HIV services in London were e-mailed a survey asking about past HAV vaccination policy, requirements for vaccine, logistics of vaccine provision, acute HAV infection reporting and contact tracing policy.Results14/17 (82%) NHS Trusts, representing 23 clinics responded to the survey.Abstract P195 Table 1HAV Vaccination Provision for MSM in GUM and HIV clinics in LondonNever stopped in GUMStopped in GUM in last 2 yearsStopped in GUM in last 2–10 yearsStopped in GUM >10 years ago3/23 (13%)6/23 (26%)7/23 (30%)7/23 (30%)Offered to all HIV+ patientsOffered to selected HIV+ patients only20/23 (87%)3/23 (13%)4/23 (17%) GUM clinics restarted routine vaccination in 2017. Only 3 HIV clinics were able to estimate background HAV immunity in their MSM as being 70–90% immune/vaccinated. The barriers to roll out of vaccination were identified as cost/funding (17/23 74%); logistics of provision (11/23 48%) and vaccine supply difficulties (7/23 30%). All clinics would contact trace acute HAV cases internally, 6/23 (23%) would notify the Health Protection Team by phone and the rest would notify using the BASHH/PHE notification form.DiscussionThe provision of HAV vaccination for MSM in London GUM clinics has been variable, leading to a significant proportion of MSM potentially remaining non-immune. The main barriers to vaccination have been funding, logistics and vaccine supply. If the outbreak is to be halted, these barriers need to be overcome.