A COVID-19 Outbreak in a Large Meat-Processing Plant in England: Transmission Risk Factors and Controls.

The meat-processing industry had frequent COVID-19 outbreaks reported worldwide. In May 2021, a large meat-processing plant in the UK had an outbreak affecting 4.1% (63/1541) of workers. A rapid on-site investigation was conducted to understand the virus transmission risk factors and control measures. This included observational assessments of work activities, control measures, real-time environmental measurements and surface microbial sampling. The production night-shift attack rate (11.6%, 44/380) was nearly five times higher than the production day-shift (2.4%, 9/380). Shared work transport was provided to 150 staff per dayshift and 104 per nightshift. Production areas were noisy (≥80 dB(A)) and physical distancing was difficult to maintain. Face visors were mandatory, additional face coverings were required for some activities but not always worn. The refrigeration system continuously recirculated chilled air. In some areas, the mean temperature was as low as 4.5 °C and mean relative humidity (RH) was as high as 96%. The adequacy of ventilation in the production areas could not be assessed reliably using CO2, due to the use of CO2 in the packaging process. While there were challenges in the production areas, the observed COVID-19 control measures were generally implemented well in the non-production areas. Sixty surface samples from all areas were tested for SARS-CoV-2 RNA and 11.7% were positive. Multi-layered measures, informed by a workplace specific risk assessment, are required to prevent and control workplace outbreaks of COVID-19 or other similar respiratory infectious diseases.

Standards of care for occupational asthma: an update.

BACKGROUND: The British Thoracic Society (BTS) Standards of Care (SoC) Committee produced a standard of care for occupational asthma (OA) in 2008, based on a systematic evidence review performed in 2004 by the British Occupational Health Research Foundation (BOHRF). METHODS: BOHRF updated the evidence base from 2004-2009 in 2010. RESULTS: This article summarises the changes in evidence and is aimed at physicians, nurses and other healthcare professionals in primary and secondary care, occupational health and public health and at employers, workers and their health, safety and other representatives. CONCLUSIONS: Various recommendations and evidence ratings have changed in the management of asthma that may have an occupational cause.

Sensitization to wheat flour and enzymes and associated respiratory symptoms in British bakers.

RATIONALE: Current literature suggests that flour exposed workers continue to be at risk of allergic sensitization to flour dust and respiratory ill health. OBJECTIVES: A cross-sectional study of 225 workers currently potentially exposed to flour dust in British bakeries was performed to identify predictors of sensitization to wheat flour and enzymes. RESULTS: Work-related nasal irritation was the most commonly reported symptom (28.9%) followed by eye irritation (13.3%) and work-related cough or chest tightness (both 10.2%). Work-related chest tightness was significantly associated (OR 7.9, 1.3-46.0) with co-sensitization to wheat flour and any added enzyme. Working at a bakery with inadequate control measures was not a risk factor for reporting work-related respiratory symptoms (OR 1.3, 0.4-3.7). Fifty-one workers were atopic and 23 (14%) were sensitized to workplace allergens. Atopy was the strongest predictive factor (OR 18.4, 5.3-64.3) determining sensitization. Current versus never smoking (OR 4.7, 1.1-20.8) was a significant risk factor for sensitization to wheat flour or enzymes in atopic workers only, corrected for current level and duration of exposure. This effect was not seen in non-atopic workers (OR 1.9, 0.2-17.9). Evidence of sensitization to less commonly encountered allergens was also seen to Aspergillus niger derived cellulase, hemicellulase and xylanase mix, in addition to glucose oxidase and amyloglucosidase mix. CONCLUSIONS: The combination of health surveillance and exposure control in this population has been insufficient to prevent clinically significant workplace sensitization. Smoking may pose an additional risk factor for sensitization in atopic workers. Am. J. Ind. Med. 52:133-140, 2009.

Variability in the diagnosis of occupational asthma and implications for clinical practice.

PURPOSE OF REVIEW: The purpose of this review is to provide a summary of recent evidence relating to occupational asthma diagnosis. RECENT FINDINGS: Recent evidence suggests that whilst prolonged asthmagen exposure worsens the prognosis, many steps in the diagnostic process are problematic for workers with possible occupational asthma. Certain workers suffer delay prior to specialist assessment, and assessment itself may be of variable quality. Emerging evidence suggests that whilst experts agree about certain aspects of case assessment, there is still likely to be variation in clinical practice. Implications of this variation for the workers assessed are relatively under researched. SUMMARY: Future research needs to focus not only on improving diagnostic testing, but also on improving consistency and agreement over diagnosis.

Occupational asthma: an assessment of diagnostic agreement between physicians.

OBJECTIVES: To investigate the levels of agreement between expert respiratory physicians when making a diagnosis of occupational asthma. METHODS: 19 cases of possible occupational asthma were identified as part of a larger national observational cohort. A case summary for each case was then circulated to 12 physicians, asking for a percentage likelihood, from the supplied information, that this case represented occupational asthma. The resulting probabilities were then compared between physicians using Spearman's rank correlation and Cohen's kappa coefficients. RESULTS: Agreement between the 12 physicians for all 19 cases was generally good as assessed by Spearman's rank correlation. For all 66 physician-physician interactions, 45 were found to correlate significantly at the 5% level. The agreement assessed by kappa analysis was more variable, with a median kappa value of 0.26, (range -0.2 to +0.76), although 7 of the physicians agreed significantly (p<0.05) with >or=5 of their colleagues. Only in one case did the responses for probability of occupational asthma all exceed the "on balance" 50% threshold, although 12 of the 19 cases had an interquartile range of probabilities not including 50%, implying "on balance" agreement. The median probability values for each physician (all assessing the identical 19 cases) varied from 20% to 70%. Factors associated with a high probability rating were the presence of a positive serial peak expiratory flow Occupation Asthma SYStem (OASYS)-2 chart, and both the presence of bronchial hyper-reactivity and significant change in reactivity between periods of work and rest. CONCLUSIONS: Despite the importance of the diagnosis of occupational asthma and reasonable physician agreement, certain variations in diagnostic assessment were seen between UK expert centres when assessing paper cases of possible occupational asthma. Although this may in part reflect the absence of a normal clinical consultation, a more unified national approach to these patients is required.

Work-related asthma symptoms and attitudes to the workplace.

BACKGROUND: The Health & Safety Executive estimate that between 1500-3000 UK workers develop asthma through potentially avoidable workplace exposures each year. AIMS: To assess the perception of health, safety and the work environment by workers with symptoms suggestive of occupational asthma. METHODS: A total of 97 workers referred to hospital specialists with symptoms suggestive of occupational asthma were studied in order to investigate their attitudes to the workplace, safety and health. A qualitative study design using semi-structured telephone interviews at 2 months and 12 months following enrolment was used at 6 national UK centres with a special interest in occupational asthma. RESULTS: Many workers in the study felt let down by the workplace and management and perceived that a lack of health and safety measures had contributed to the development of their asthma symptoms. Many workers felt that their employers were 'uncaring' and were pursuing or considering medico-legal cases against them. CONCLUSIONS: Workers' perception of risk influences their behaviour in the workplace, and their own health beliefs potentially create barriers to changing this. It is essential to consider workers' perceptions when developing strategies to effect change within the workplace.

Hand-arm vibration syndrome in South African gold miners.

BACKGROUND: Hand-arm vibration syndrome (HAVS) is associated with the use of hand-held vibrating tools. Affected workers may experience symptoms of tingling, numbness, loss of grip strength and pain. Loss of dexterity may impair everyday activities, and potentially increase the risk of occupational accidents. Although high vibration levels (up to 31 m/s(2)) have been measured in association with rock drills, HAVS has not been scientifically evaluated in the South African mining industry. AIMS: The aim of this study was to determine the prevalence and severity of HAVS in South African gold miners, and to identify the tools responsible. METHODS: A cross-sectional study was conducted in a single South African gold-mine. Participants were randomly selected from mineworkers returning from annual leave, comprising 156 subjects with occupational exposure to vibration, and 140 workers with no exposure. Miners who consented to participate underwent a clinical HAVS assessment following the UK Health and Safety Laboratory protocol. RESULTS: The prevalence of HAVS in vibration-exposed gold miners was 15%, with a mean latent period of 5.6 years. Among the non-exposed comparison group, 5% had signs and symptoms indistinguishable from HAVS. This difference was statistically significant (P < 0.05). All the cases of HAVS gave a history of exposure to rock drills. CONCLUSIONS: The study has diagnosed the first cases of HAVS in the South African mining industry. The prevalence of HAVS was lower than expected, and possible explanations for this may include a survivor population, and lack of vascular symptom reporting due to warm-ambient temperatures.

Are we failing workers with symptoms suggestive of occupational asthma?

AIMS: To assess the route to secondary care for patients with possible occupational asthma, and to document the duration of workrelated symptoms and referral times. METHODS: Consecutive patients with suspected occupational asthma were recruited to a case series from six secondary care clinics with an interest in occupational asthma. Semi-structured interviews were performed and hospital case notes were reviewed to summarise relevant investigations and diagnosis. RESULTS: 97 patients were recruited, with a mean age of 44.2 years (range 24-64), 51 of whom (53%) had occupational asthma confirmed as a diagnosis. Most (96%) had consulted their general practitioner (GP) at least once with work-related respiratory symptoms, although these had been present for a mean of 44.6 months (range 0-320 months) on presentation to secondary care. Patients experienced a mean delay for assessment in secondary care of 4 years (range 1-27 years) following presentation in primary care. CONCLUSIONS: Significant diagnostic delay currently occurs for patients with occupational asthma in the UK.

Reproducibility and validity of a Yan-style portable citric acid cough challenge.

Although many different methods of measuring cough reflex sensitivity have been published, few are simple enough to use outside of a hospital or laboratory environment. The aim of this study was to develop a simple, quick, and portable cough challenge, assess its reproducibility, and compare its results with those measured by an existing established hospital protocol. Twenty-five volunteers performed cough challenges based on an established hospital dosimeter protocol, and, on a separate occasion, by a protocol inhaling citric acid from DeVilbiss 40 hand-held nebulisers (citric acid concentrations of 10-3000 mM). Reproducibility of the hand-held cough challenge was assessed in 11 volunteers. Cough thresholds were consistently higher by the hand-held method than by the hospital dosimeter method. The geometric mean citric acid concentrations causing two coughs (threshold D2) were 3.14 and 2.77 log mM, respectively (p<0.001). The geometric mean (95% CI) difference between the tests was 0.51 log mM (0.18-0.83) of the average of the two values. Cough D2 thresholds attained by the two techniques did, however, show significant correlation (r=0.95, p<0.0001). The coefficient of repeatability for the hand-held method was 0.40 log mM. Administering citric acid from DeVilbiss 40 hand-held nebulisers offers a rapid, portable, and reproducible cough challenge in healthy volunteers. The results correlate well with an existing Mefar dosimeter challenge, but give two to three times greater cough thresholds.

An evaluation of occupational health services within the NHS in London.

AIMS: To establish the nature, extent and organization of occupational health service provision for employees within the National Health Service (NHS) in London and to review the systems for monitoring performance. METHODS: Human resources directors and occupational health managers were contacted from a random selection of NHS trusts in the London area and invited to complete an interviewer-led questionnaire. RESULTS: All seventeen trusts interviewed claimed to provide an occupational health service to their employees, with 88% providing this service in-house. The organization of the services varied, although most resided within the human resources function. Only 29% of the trusts could provide a written occupational health policy. Teaching hospital trusts had the most qualified and the highest numbers of medical staff. District/General hospital trusts had the least qualified clinical staff. Although most trusts were able to provide a comprehensive range of services, 87% of occupational health managers felt they could only provide a reactive service. Income was generated from non-NHS sources by 88% of the trusts and all were aware of NHS Plus. There was an indication that some trusts assigned NHS Plus status did not meet the standard of NHS Plus, although the survey took place only 3 months after the launch of NHS Plus. CONCLUSIONS: There was a significant variation in the nature and extent of occupational health services in the NHS trusts. As a consequence, there may be differences in the level of occupational health service available to staff across the NHS in London.

Job categories and their effect on exposure to fungal alpha-amylase and inhalable dust in the U.K. baking industry.

Enzymes in flour improver, in particular fungal alpha-amylase, are known to be a significant cause of respiratory allergy in the baking industry. This study measured total inhalable dust and fungal alpha-amylase exposures in U.K. bakeries, mills, and a flour improver production and packing facility and determined whether assignment of job description could identify individuals with the highest exposures to fungal alpha-amylase and inhalable dust. A total of 117 personal samples were taken for workers in 19 bakeries, 2 mills, and a flour improver production and packing facility and were analyzed using a monoclonal based immunoassay. Occupational hygiene surveys were undertaken for each site to assign job description and identify individuals who worked directly with flour improvers. Analysis of exposure data identified that mixers and weighers from large bakeries had the highest exposures to both inhalable dust and fungal alpha-amylase among the different categories of bakery workers (p<.01). Currently, the maximum exposure limit for flour dust in the United Kingdom is 10 mg/m(3) (8-hour time-weighted average reference period). In this study 25% of the total dust results for bakers exceeded 10 mg/m(3), and interestingly, 63% of the individuals with exposure levels exceeding 10 mg/m(3) were weighers and mixers. Individuals who worked directly with flour improvers were exposed to higher levels of both inhalable dust and fungal alpha-amylase (p<.01) than those who were not directly handling these products. Before sensitive immunoassays were utilized for the detection of specific inhalable allergens, gravimetric analysis was often used as a surrogate. There was a weak relationship between inhalable dust and fungal alpha-amylase exposures; however, inhalable dust levels could not be used to predict amylase exposures, which highlights the importance of measuring both inhalable dust and fungal alpha-amylase exposures.