Acceptability of digital vending machines to access STI and HIV tests in two UK cities

OBJECTIVES

Prompt HIV and STI diagnosis and treatment is a public health priority and relies on accessible testing. Technology-based approaches to distribute test kits have the potential to increase access to testing. We evaluated the acceptability and uptake of vending machines in publicly available settings in Brighton and Hove (BH) and Bristol, North Somerset and South Gloucestershire (BNSSG), to distribute HIV rapid self-test and STI self-sample kits.

METHODS

Seven machines were installed in BH and four in BNSSG. User characteristics, proportion of kits returned and test results, taken from the machine database and clinic records, combined with online questionnaires completed by self-recruited users and analysed using Stata and SPSS.

RESULTS

2536 kits were dispensed over 12 months (April 2022 to March 2023). The STI self-sample kits were most popular (74% of vends). 78% of kits dispensed were among users aged 16-35 years and 56% identified as male. 68% and 59% of users had either not tested in the last 12 months or never tested for HIV and STIs, respectively. 51% of STI kits were returned via post, lower than the local online service (65%). 208 users completed questionnaires. Convenience, desire for instant access and increased confidentiality were the most common reasons for using machines. 92% of respondents thought the machines were user-friendly and 97% would recommend the service. Concerns about safety and privacy while using the machine were reported by 42% and 66% of respondents.

CONCLUSIONS

This study demonstrates that vending machines are an acceptable and effective means of accessing infrequent or never testers in the general population and can act as a horizontal intervention to tackle HIV and STIs. Research is needed to understand optimal machine locations to assure privacy and safety along with the long-term impact on sexual health services.

Acceptability and facilitators of and barriers to point-of-care HIV testing in a homeless-focused service in Gloucestershire: a qualitative evaluation

OBJECTIVES

Late HIV diagnosis increases the risks of onward transmission, morbidity and mortality. Rapid point-of-care testing (POCT) reaches people who have never been tested and people living with HIV who are undiagnosed. This study explored the acceptability and feasibility of HIV POCT from the perspectives of service providers and users.

METHODS

A pilot study introduced HIV POCT to one service in Gloucestershire, England. Eleven semi-structured interviews with service users and a focus group with three service providers were conducted. The Theoretical Framework of Acceptability and the Theoretical Domains Framework were used to design the topic guide and analysis.

RESULTS

Acceptability of HIV POCT was high. Seven facilitators were identified (e.g. understanding the test purpose and process), alongside two potential barriers, one relevant to service providers and users (anxiety) and the other to service users (stigma).

CONCLUSIONS

To maximize the benefits of implementation of HIV POCT, health care providers require appropriate training and supervision to offer and administer POCT.

The epidemiology and management of clusters of invasive meningococcal disease in England, 2010-15

BACKGROUND

Guidance for public health management of invasive meningococcal disease (IMD) in in England recommends the use of antibiotic chemoprophylaxis and vaccination. We summarized clinical and epidemiological data collected during routine management of IMD clusters in England.

METHODS

Data on epidemiology and operational decisions for public health management were reviewed for clusters between April 2010 and December 2015.

RESULTS

Clusters were generally 2-3 cases (53/58; 91%) within a single age band <18-years. Nurseries (n = 20, 34%), households/social networks (n = 14, 24%) and schools (n = 10, 17%) were the commonest settings. Chemoprophylaxis alone was used in 36 (58%) clusters, including most serogroup B clusters (31/41; 76%). Chemoprophylaxis and vaccination was used in a further 20 (32%) clusters. Vaccine was delivered promptly (<7 days). Four clusters had cases with onset post-chemoprophylaxis; no clusters recorded cases with onset post-vaccination. No pattern was observed between interventions and setting/population at risk, and interventions were consistent with national guidance. Challenges to management included logistical issues related to intervention delivery.

CONCLUSIONS

Public health management of IMD clusters presents challenges in decision-making and implementation of interventions. Nonetheless, few cases were observed following intervention. Responses were consistent with national guidance. A systematic data collection tool should be developed to support future evaluation.

Developing a model to predict individualised treatment for gonorrhoea: a modelling study

OBJECTIVE

To develop a tool predicting individualised treatment for gonorrhoea, enabling treatment with previously recommended antibiotics, to reduce use of last-line treatment ceftriaxone.

DESIGN

A modelling study.

SETTING

England and Wales.

PARTICIPANTS

Individuals accessing sentinel health services.

INTERVENTION

Developing an Excel model which uses participants' demographic, behavioural and clinical characteristics to predict susceptibility to legacy antibiotics. Model parameters were calculated using data for 2015-2017 from the Gonococcal Resistance to Antimicrobials Surveillance Programme.

MAIN OUTCOME MEASURES

Estimated number of doses of ceftriaxone saved, and number of people delayed effective treatment, by model use in clinical practice. Model outputs are the predicted risk of resistance to ciprofloxacin, azithromycin, penicillin and cefixime, in groups of individuals with different combinations of characteristics (gender, sexual orientation, number of recent sexual partners, age, ethnicity), and a treatment recommendation.

RESULTS

Between 2015 and 2017, 8013 isolates were collected: 64% from men who have sex with men, 18% from heterosexual men and 18% from women. Across participant subgroups, stratified by all predictors, resistance prevalence was high for ciprofloxacin (range: 11%-51%) and penicillin (range: 6%-33%). Resistance prevalence for azithromycin and cefixime ranged from 0% to 13% and for ceftriaxone it was 0%. Simulating model use, 88% of individuals could be given cefixime and 10% azithromycin, saving 97% of ceftriaxone doses, with 1% of individuals delayed effective treatment.

CONCLUSIONS

Using demographic and behavioural characteristics, we could not reliably identify a participant subset in which ciprofloxacin or penicillin would be effective. Cefixime resistance was almost universally low; however, substituting ceftriaxone for near-uniform treatment with cefixime risks re-emergence of resistance to cefixime and ceftriaxone. Several subgroups had low azithromycin resistance, but widespread azithromycin monotherapy risks resistance at population level. However, this dataset had limitations; further exploration of individual characteristics to predict resistance to a wider range of legacy antibiotics may still be appropriate.

Risk of symptomatic COVID-19 due to aircraft transmission: a retrospective cohort study of contact-traced flights during England's containment phase

Background

Knowledge gaps remain regarding SARS‐CoV‐2 transmission on flights. We conducted a retrospective cohort study to estimate risk of acquiring symptomatic SARS‐CoV‐2 on aircraft, to inform contact tracing and infection control efforts.

Methods

We identified co‐passengers of infectious passengers on 18 England‐bound flights from European cities up to 12/03/2020, using manifests received for contact tracing. Infectious passengers were laboratory‐confirmed cases with symptom onset from 7 days before to 2 days after the flight. Possible aircraft‐acquired cases were laboratory‐confirmed with onset 3‐14 days post‐flight with no known non‐flight exposure. Manifests was merged with the national case management dataset (identifying cases, onset dates, contact tracing status) and the national COVID‐19 linelist. Contact tracing notes were reviewed to identify non‐flight exposures. We calculated attack rates (ARs) among all co‐passengers and within subgroups, including by distance from infectious cases and number of infectious cases on‐board.

Results

There were 55 infectious passengers and 2313 co‐passengers, including 2221 flight‐only contacts. Five possible aircraft‐acquired cases were identified; ARs of 0.2% (95%CI 0.1‐0.5) among all flight‐only contacts and 3.8% (95%CI 1.3‐10.6) among contact‐traced flight‐only contacts sat within a two‐seat radius. The AR among 92 co‐travellers with known non‐flight exposure to infectious cases was 13.0% (95%CI 7.6%‐21.4%). There were insufficient numbers to assess differences between subgroups.

Conclusion

We conclude that risk of symptomatic COVID‐19 due to transmission on short to medium‐haul flights is low, and recommend prioritising contact‐tracing of close contacts and co‐travellers where resources are limited. Further research on risk on aircraft is encouraged.

Clonal expansion of community-associated meticillin-resistant Staphylococcus aureus (MRSA) in people who inject drugs (PWID): prevalence, risk factors and molecular epidemiology, Bristol, United Kingdom, 2012 to 2017

Background: In 2015, Bristol (South West England) experienced a large increase in cases of meticillin-resistant Staphylococcus aureus (MRSA) infection in people who inject drugs (PWID).

Aim: We aimed to characterise and estimate the prevalence of MRSA colonisation among PWID in Bristol and test evidence of a clonal outbreak.

Methods: PWID recruited through an unlinked-anonymous community survey during 2016 completed behavioural questionnaires and were screened for MRSA. Univariable logistic regression examined associations with MRSA colonisation. Whole-genome sequencing used lineage-matched MRSA isolates, comparing PWID (screening and retrospective bacteraemia samples from 2012-2017) with non-PWID (Bristol screening) in Bristol and national reference laboratory database samples.

Results: The MRSA colonisation prevalence was 8.7% (13/149) and was associated with frequently injecting in public places (odds ratio (OR): 5.5; 95% confidence interval (CI):1.34–22.70), recent healthcare contact (OR: 4.3; 95% CI: 1.34–13.80) and injecting in groups of three or more (OR: 15.8; 95% CI: 2.51–99.28). People reporting any one of: injecting in public places, injection site skin and soft tissue infection or hospital contact accounted for 12/13 MRSA positive cases (sensitivity 92.3%; specificity 51.5%). Phylogenetic analysis identified a dominant clade associated with infection and colonisation among PWID in Bristol belonging to ST5-SCCmecIVg.

Conclusions: MRSA colonisation in Bristol PWID is substantially elevated compared with general population estimates and there is evidence of clonal expansion, community-based transmission and increased infection risk related to the colonising strain. Targeted interventions, including community screening and suppression therapy, education and basic infection control are needed to reduce MRSA infections in PWID.

Detection in the United Kingdom of the Neisseria gonorrhoeae FC428 clone, with ceftriaxone resistance and intermediate resistance to azithromycin, October to December 2018

We describe detection in the United Kingdom (UK) of the drug-resistant Neisseria gonorrhoeae FC428 clone, with ceftriaxone resistance and intermediate azithromycin resistance. Two female patients developed infection following contact with UK-resident men from the same sexual network linked to travel to Ibiza, Spain. One case failed treatment with ceftriaxone, and azithromycin and gentamicin, before successful treatment with ertapenem. Both isolates had indistinguishable whole-genome sequences. Urgent action is essential to contain this drug-resistant strain.

Outcomes of Mental Health Screening for United Kingdom Nationals Affected by the 2015-2016 Terrorist Attacks in Tunisia, Paris, and Brussels

Following several terrorist attacks in 2015 and 2016, a national program was set up to identify and support residents of England whose mental health had been affected. We report the outcomes of the program's screening and assessment components. Questionnaires and information about the program were mailed to 483 people and 49 families known to the police. Individuals who screened positive on an assessment for posttraumatic stress disorder, anxiety, depression, increased smoking, or problematic alcohol consumption were offered clinical assessment and referred to an appropriate National Health Service (NHS) service, if required. Of the 195 eligible people who returned our questionnaires, 179 (91.8%) screened positive on one or more measure. Following clinical assessment, 78 adults and three children were referred for treatment. The program was broadly successful in facilitating access to services. However, most people who had been directly exposed to the attacks did not participate and data protection issues limited communication with those who were affected. Further discussion of data protection concerns may help future programs operate more efficiently.

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.

National outbreak of Shiga toxin-producing Escherichia coli O157:H7 linked to mixed salad leaves, United Kingdom, 2016

We investigated a large outbreak of Escherichia coli O157 in the United Kingdom (UK) with 165 cases between 31 May and 29 July 2016. No linked cases were reported in other countries. Cases were predominately female (n = 128) and adult (n = 150), 66 attended hospital and nine had features of haemorrhagic uraemic syndrome. A series of epidemiological studies (case-control, case-case, ingredients-based and venue-based studies) and supply chain investigations implicated mixed salad leaves from Supplier A as the likely outbreak vehicle. Whole genome sequencing (WGS) indicated a link with strains from the Mediterranean and informed the outbreak control team to request that Supplier A cease distributing salad leaves imported from Italy. Microbiological tests of samples of salad leaves from Supplier A were negative. We were unable to confirm the source of contamination or the contaminated constituent leaf although our evidence pointed to red batavia received from Italy as the most likely vehicle. Variations in Shiga toxin-producing E.coli surveillance and diagnosis may have prevented detection of cases outside the UK and highlights a need for greater standardisation. WGS was useful in targeting investigations, but greater coverage across Europe is needed to maximise its potential.

The Antibiotic Guardian campaign: a qualitative evaluation of an online pledge-based system focused on making better use of antibiotics

BACKGROUND

The Antibiotic Guardian Campaign was developed to increase commitment to reducing Antimicrobial Resistance (AMR), change behaviour and increase knowledge through an online pledge system for healthcare professionals and members of the public to become Antibiotic Guardians (AG). This qualitative evaluation aimed to understand AG experiences of the campaign and perceived impact on behaviour.

METHODS

Ninety-four AGs (48 via a survey and 46 who had agreed to future contact) were invited to participate in a telephone semi-structured interview. The sample was based on self-identification as a healthcare professional or a member of the public, pledge group (e.g. adults, primary care prescribers etc.), pledge and gender. Interviews explored how participants became aware of the campaign, reasons for joining, pledge choices, responses to joining and views about the campaign's implementation. Interviews were analysed using the Framework Method.

RESULTS

Twenty-two AGs (10 healthcare professionals and 12 members of the public) were interviewed. AGs became aware of the campaign through professional networks and social media, and were motivated to join by personal and professional concern for AMR. Choice of pledge group and pledge were attributed to relevance and potential impact on AMR and the behaviour of others through pledge enactment and promotion of the campaign. Most AGs could not recall their pledge unprompted. Most felt they fulfilled their pledge, although this reflected either behaviour change or the pledge reinforcing pre-existing behaviour. The campaign triggered AGs to reflect on AMR related behaviour and reinforced pre-existing beliefs. Several AGs promoted the campaign to others. Responding collectively as part of the campaign was thought to have a greater impact than individual action. However, limited campaign visibility was observed and the campaign was perceived to have restricted ability to reach those unaware of AMR.

CONCLUSIONS

AGs were motivated to reduce AMR and most felt they fulfilled their pledges although for many this appeared to be through reinforcement of existing behaviours. We recommend that the campaign engages those without pre-existing knowledge of AMR by increasing its visibility, capitalising on the diffusion of its message and including more awareness-raising content for those with limited AMR knowledge.

Ongoing outbreak of invasive and non-invasive disease due to group A Streptococcus (GAS) type emm66 among homeless and people who inject drugs in England and Wales, January to December 2016

We report an outbreak of invasive and non-invasive disease due to an unusual type of Streptococcus pyogenes(group A Streptococcus, emm66) among a vulnerable, largely homeless population in southern England and Wales, detected in September 2016. Twenty-seven confirmed cases were subsequently identified between 5 January and 29 December 2016; 20 injected drugs and six reported problematic alcohol use. To date, we have ruled out drug-related vehicles of infection and identified few common risk factors.

Impact of a United Kingdom-wide campaign to tackle antimicrobial resistance on self-reported knowledge and behaviour change

BACKGROUND

As part of the 2014 European Antibiotic Awareness Day plans, a new campaign called Antibiotic Guardian (AG) was launched in the United Kingdom, including an online pledge system to increase commitment from healthcare professionals and members of the public to reduce antimicrobial resistance (AMR). The aim of this evaluation was to determine the impact of the campaign on self-reported knowledge and behaviour around AMR.

METHODS

An online survey was sent to 9016 Antibiotic Guardians (AGs) to assess changes in self-reported knowledge and behaviour (outcomes) following the campaign. Logistic regression models, adjusted for variables including age, sex and pledge group (pledging as member of public or as healthcare professional), were used to estimate associations between outcomes and AG characteristics.

RESULTS

2478 AGs responded to the survey (27.5 % response rate) of whom 1696 (68.4 %) pledged as healthcare professionals and 782 (31.6 %) as members of public (similar proportions to the total number of AGs). 96.3 % of all AGs who responded had prior knowledge of AMR. 73.5 % of participants were female and participants were most commonly between 45 and 54 years old. Two thirds (63.4 %) of participants reported always acting according to their pledge. Members of the public were more likely to act in line with their pledge than professionals (Odds Ratio (OR) =3.60, 95 % Confidence Interval (CI): 2.88-4.51). Approximately half of participants (44.5 %) (both healthcare professionals and members of public) reported that they acquired more knowledge about AMR post-campaign. People that were confused about AMR prior to the campaign acquired more knowledge after the campaign (OR = 3.10, 95 % CI: 1.36-7.09). More participants reported a sense of personal responsibility towards tackling AMR post-campaign, increasing from 58.3 % of participants pre-campaign to 70.5 % post-campaign.

CONCLUSION

This study demonstrated that the campaign increased commitment to tackling AMR in both healthcare professional and member of the public, increased self-reported knowledge and changed self-reported behaviour particularly among people with prior AMR awareness. Online pledge schemes can be an effective and inexpensive way to engage people with the problem of AMR especially among those with prior awareness of the topic.

Control selection methods in recent case-control studies conducted as part of infectious disease outbreaks

Successful investigation of national outbreaks of communicable disease relies on rapid identification of the source. Case-control methodologies are commonly used to achieve this. We assessed control selection methods used in recently published case-control studies for methodological and resource issues to determine if a standard approach could be identified. Neighbourhood controls were the most frequently used method in 53 studies of a range of different sizes, infections and settings. The most commonly used method of data collection was face to face interview. Control selection issues were identified in four areas: method of identification of controls, appropriateness of controls, ease of recruitment of controls, and resource requirements. Potential biases arising from the method of control selection were identified in half of the studies assessed. There is a need to develop new ways of selecting controls in a rapid, random and representative manner to improve the accuracy and timeliness of epidemiological investigations and maximise the effectiveness of public health interventions. Innovative methods such as prior recruitment of controls could improve timeliness and representativeness of control selection.

Evaluation of the measles, mumps and rubella vaccination catch-up campaign in England in 2013

In January-March 2013 in England, confirmed measles cases increased in children aged 10-16 years. In April-September 2013, the National Health System and Public Health England launched a national measles-mumps-rubella (MMR) campaign based on data from Child Health Information Systems (CHIS) estimating that approximately 8% in this age group were unvaccinated. We estimated coverage at baseline, and, of those unvaccinated (target), the proportion vaccinated up to 20/08/2013 (mid-point) to inform further public health action. We selected a sample of 6644 children aged 10-16 years using multistage sampling from those reported unvaccinated in CHIS at baseline and validated their records against GP records. We adjusted the CHIS MMR vaccine coverage estimates correcting by the proportion of vaccinated children obtained through sample validation. We validated 5179/6644 (78%) of the sample records. Coverage at baseline was estimated as 94.7% (95% confidence intervals, CI: 93.5-96.0%), lower in London (86.9%, 95%CI: 83.0-90.9%) than outside (96.1%, 95%CI 95.5-96.8%). The campaign reached 10.8% (95%CI: 7.0-14.6%) of the target population, lower in London (7.1%, 95%CI: 4.9-9.3) than in the rest of England (11.4%, 95%CI: 7.0-15.9%). Coverage increased by 0.5% up to 95.3% (95% CI: 94.1-96.4%) but an estimated 210,000 10-16 year old children remained unvaccinated nationally. Baseline MMR coverage was higher than previously reported and was estimated to have reached the 95% campaign objective at midpoint. Eleven per cent of the target population were vaccinated during the campaign, and may be underestimated, especially in London. No further national campaigns are needed but targeted local vaccination activities should be considered.

Do sexual health campaigns work? An outcome evaluation of a media campaign to increase chlamydia testing among young people aged 15-24 in England

Background

A national multimedia campaign was launched in January 2010, to increase the proportion of young people tested for chlamydia. This study aimed to evaluate the impact of the campaign on the coverage and positivity within the National Chlamydia Screening Programme (NSCP) in England.

Method

An interrupted time series of anonymised NCSP testing reports for England for a 27 month period (1st April 2008 to 30th June 2010) was analysed. Reports were assigned to a pre-campaign, campaign and post campaign phase according to the test date. Exclusion criteria included tests for clinical reasons, contacts of known cases, and tests returned from prisons or military services.

Negative binomial and logistic regression modelling was used to provide an estimate for the change in coverage and positivity, during, and after the campaign and estimates were adjusted for secular and cyclical trends.

Results

Adjusting for cyclical and secular trends, there was no change in the overall testing coverage either during (RR: 0.91; 95% CI: 0.72-1.14) or after (RR: 0.88; 95%CI: 0.69-1.11) the campaign. The coverage varied amongst different socio-demographic groups, testing of men increased during the campaign phase while testing of people of black and other ethnic groups fell in this phase. The positivity rate was increased during the campaign (OR: 1.18; 95% CI 1.13-1.23) and further increased in the post-campaign phase (OR: 1.40; 95% CI 1.30-1.51). The proportion of chlamydia infections detected increased for all socio-demographic and self-reported sexual behaviour groups both during and after the campaign.

Conclusion

The uptake of chlamydia testing rose during the campaign; however, this apparent increase was not maintained once overall trends in testing were taken into account. Nonetheless, once secular and cyclical trends were controlled for, the campaign was associated with an increased positivity linked to increased testing of high risk individuals groups in the target population who were previously less likely to come forward for testing. However, our study indicated that there may have been a disparity in the impact of the campaign on different population groups. The content and delivery of ongoing and future information campaigns aimed at increasing chlamydia screening should be carefully developed so that they are relevant to all sections of the target population.

Gastro-intestinal poisoning due to consumption of daffodils mistaken for vegetables at commercial markets, Bristol, United Kingdom

INTRODUCTION

In February 2012, we investigated a cluster of people who presented at a local emergency department with sudden onset of vomiting after mistaken consumption of daffodils.

METHODS

We interviewed patients to collect information on daffodil purchase and consumption. With Local Authority we investigated points of sale to understand the source of confusion.

RESULTS

We identified 11 patients (median age: 23 years, range 5-60 years, eight females) among Bristol (UK) residents of Chinese origin. The most commonly reported symptoms were vomiting (n = 11) and nausea (n = 9) that developed within 12 h of daffodil consumption. There were no hospitalisations or deaths. Patients were clustered in two family dinners and one party. Bunches of pre-bloom daffodil stalks were purchased in two stores of one supermarket chain, which displayed daffodils next to vegetables, not marked as non-edible. Patients cooked and consumed daffodils mistaking them for Chinese chives/onions.

DISCUSSION

Gastro-intestinal poisoning should be considered in differential diagnoses of gastroenteritis. Multi-cultural societies are at risk of confusion between non-edible and edible plants. Supermarket presentation of daffodils may have contributed to mistaken consumption. We recommended explicit labelling and positioning of daffodils, away from produce. The supermarket chain introduced graphic 'non-edible' labels. No further patients were reported following action.

Ongoing outbreak of Shigella flexneri serotype 3a in men who have sex with men in England and Wales, data from 2009–2011

Diagnoses of Shigella flexneri in the United Kingdom (UK) are usually travel-related. However, since 2009, there has been an overall increase in UK-acquired cases. The Health Protection Agency has been investigating a national outbreak of S. flexneri detected in 2011 and which is still ongoing. Cases occurred mostly in men who have sex with men and were of serotype 3a. The investigation aimed at obtaining epidemiological data to inform targeted outbreak management and control.

Ongoing outbreak of Shigella flexneri serotype 3a in men who have sex with men in England and Wales, data from 2009-2011

Diagnoses of Shigella flexneri in the United Kingdom (UK) are usually travel-related. However, since 2009, there has been an overall increase in UK-acquired cases. The Health Protection Agency has been investigating a national outbreak of S. flexneri detected in 2011 and which is still ongoing. Cases occurred mostly in men who have sex with men and were of serotype 3a. The investigation aimed at obtaining epidemiological data to inform targeted outbreak management and control.

National outbreak of Salmonella Java phage type 3b variant 9 infection using parallel case-control and case-case study designs, United Kingdom, July to October 2010

Between July and October 2010, a national outbreak comprising 136 cases of Salmonella Java phage type 3b variant 9 was identified by the Health Protection Agency. Most cases were female. Cases had a median age of 39.5 years and lived in London, the South East and East of England. Parallel case–control and case–case study designs were undertaken to test the generated hypotheses. The case–case study aimed to examine if the infection was associated with eating food items purchased from commercial catering settings, and the reference group comprised non-travel related cases of S. Enteritidis infected during the same time period as the cases. The case–control study was designed to examine if the infection was associated with specific food items purchased from commercial catering settings, and recruited case-nominated controls. However, in response to poor recruitment we adapted our methods to investigate food exposures in the same way. Results of epidemiological investigations are compatible with salad vegetables as the potential source, but no common suppliers of salad were identified and no organisms were isolated from environmental and food samples. Limitations in the case–control study highlight the potential value of using a combination of epidemiological methods to investigate outbreaks.

National outbreak of Salmonella Java phage type 3b variant 9 infection using parallel case–control and case–case study designs, United Kingdom, July to October 2010

Binary file ES_Abstracts_Final_ECDC.txt matches