Irish meat processing plant COVID-19 outbreak: a retrospective study

By Suchandrima BhowmikSep 27 2021

Since the onset of the coronavirus disease 2019 (COVID-19) pandemic, meat processing plants (MPP) have proved to be vulnerable to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission. Severe outbreaks have affected MMP workers throughout the world.

Study: Assessment of Environmental and Occupational Risk Factors for the Mitigation and Containment of a COVID-19 Outbreak in a Meat Processing Plant. Image Credit: industryviews/ Shutterstock

This news article was a review of a preliminary scientific report that had not undergone peer-review at the time of publication. Since its initial publication, the scientific report has now been peer reviewed and accepted for publication in a Scientific Journal. Links to the preliminary and peer-reviewed reports are available in the Sources section at the bottom of this article. View Sources

Transmission of the virus is difficult to control in such environments due to the nature of the work, environmental factors, and difficulty maintaining social distance between the workers. Clusters of COVID-19 that have originated from MPPs have been reported from several countries throughout the world.

COVID-19 outbreaks in MPPs can be large and, if not controlled, can lead to virus spillover in the community. There is considerable evidence suggesting that superspreading events play an important role in the establishment and maintenance of SARS-CoV-2 infection.

Recent studies have indicated that MPPs are one of the locations where superspreading events are most likely to occur. Therefore, workplace risk mitigation measures are required to reduce transmission and protect the workers and the wider community from contracting COVID-19.

Background

The agri-food industry of Ireland contributes to 8 percent of Ireland’s GDP and provides around 160,000 jobs. The meat processing industry is considered an important part of the agri-food sector and was an important part of the national and international food supply.

Therefore, an investigation of the risk factors for a COVID-19 outbreak in Irish meat processing plants was conducted. This also helped in the detection of new and more transmissible variants of SARS-CoV-2. Although the public health authorities had implemented several guidelines, numerous outbreaks of SARS-CoV-2 have been reported amongst Irish meat processing staff.

A new study involved a retrospective investigation of the outbreak of COVID-19 in an Irish meat plant. The study included air quality assessments, semi-structured interviews with plant management, verification of risk mitigation measures, and evaluation of operational factors.

A preprint version of the study is available on the medRxiv* server while the article undergoes peer review.

About the study

The study involved 290 workers from a particular MPP in Ireland. Due to the rising concerns on the vulnerability of MPPs to COVID-19 in Ireland, the Department of Agriculture, Food and the Marine (DAFM) carried out a pilot study of environmental and operational factors that influenced the transmission of MPPs within the meat processing facility.

The team assumed that a superspreading event occurred within the MPP, where many workers tested PCR positive. Thus, it could be hypothesized that the plant environment favored the transmission of SARS-CoV-2 via aerosols and droplets.

The selection of a particular MPP was based on certain criteria such as whether an outbreak of COVID-19 had occurred in the plant in early-mid 2020, mass PCR testing of the workers had taken place, a large proportion of the workers tested positive for SARS-CoV-2, and the primary processing of the red meat occurred at one site of the plant.

The team collected data by visiting the site of the plant. A site visit comprised an interview with the plant Emergency Response Team (ERT) and inspection of the facility to determine if the COVID-19 control measures were implemented. Air quality assessment was carried out in areas where the highest number of PCR-positive cases were reported. The concentration of carbon dioxide, humidity, temperature, and size and number of aerosols were monitored.

Study findings

The first reported positive COVID-19 case involved a worker who worked at the meat cutting or boning hall within the plant and was absent from work in early 2020. This person was found to develop symptoms as well as test positive six days later.

Overall, 42 workers out of 290 tested positive for COVID-19 on initial mass testing, and 25 worked in the boning hall. Furthermore, 111 asymptomatic workers who tested positive were reported over two months.

The initial COVID-19 mitigation measures implemented at the plant involved checking the body temperature of all the workers at entry and other public health measures that were advised during that time.

In mid-2020, the workers were advised to wear face masks and PPE, follow proper hand hygiene by using sanitizers, visitors were not allowed to enter the plant, and only essential workers were allowed on-site.

During early summer and spring of 2020, education and travel risk mitigation measures were implemented. Additionally, staff who returned after a period of absence had to follow a return to work (RTW) protocol issued by the public health authorities.

The study results also indicated that the concentration of carbon dioxide in the boning hall showed a gradual increase during working hours. This suggested that the boning hall was not well ventilated. The introduction of the air filtration device in the boning hall showed a reduction in airborne particles during the work hours in the boning hall.

Conclusion

Thus, this study provides significant insight into the role of environmental and operational factors on the transmission of COVID-19. The study shows that when the plant management worked as per the public health recommendations, it led to a significant reduction in infection among the workers and staff who worked at the plant.

Although the study effectively determined the vulnerability of MPPs in SARS-CoV-2 transmission, it had certain limitations. Firstly, the study involved only one plant where the events had occurred months ago. Secondly, the data collected was subjected to recall bias. Thirdly, the bioaerosols measurements reported in the study were limited to five days in two plant areas.

This news article was a review of a preliminary scientific report that had not undergone peer-review at the time of publication. Since its initial publication, the scientific report has now been peer reviewed and accepted for publication in a Scientific Journal. Links to the preliminary and peer-reviewed reports are available in the Sources section at the bottom of this article. View Sources