WORKPLACE EXPOSURE CONTROL OPTIONS

WORKPLACE EXPOSURE CONTROL OPTIONS

 (White paper excerpt from Occupational Health Southern Africa)

With COVID-19, it may not be possible to eliminate the hazard. The most effective exposure control measures are associated with prevention of transmission from infected persons and asymptomatic carriers; thus, the exposure pathways and the hierarchy of controls for COVID-19 are vital, i.e. engineering controls, administrative controls, safe work practices, behaviour risk management (a type of administrative control), and PPE. Thus, measures, at the source, to detect early infected and/or potentially infected persons, are key.

According to the National Institute for Communicable Diseases (NICD) case definition, persons under investigation (PUI) who should be tested for COVID-19 are those presenting with acute respiratory illness or a cough, sore throat, shortness of breath, fever ≥ 38 °C, or a history of fever.32 Initiatives to detect PUIs in workplace settings should be governed by a workplace COVID-19 policy, and should include body temperature screening at points of entry as well as measures to reduce the emission of exhaled droplets, i.e. behavioural practices such as ‘controlled-sneezing’,33 and wearing of face masks.30-32 The latter has been proven to be effective in healthcare settings where infected patients wore masks. However, it is plausible that even home-made cloth face masks will reduce the emission of droplets into the air to a certain extent. Definitely, the larger droplets will be captured, and the swelling of the cotton fibres when moisturised may prevent even smaller droplets escaping.

Regarding the droplet transmission pathway, structural measures such as simple (face) screens and barriers used in some customer-facing roles, including those of taxi/bus drivers and banking staff, might offer some degree of protection from COVID-19, compared to the more open interactive style of work that teachers or general shop staff adopt. More drastic measures would be, for example, the transition to self-scanning of purchased goods, and replacement of traditional door handles with elbow-operating systems or automatic doors. Adequate room ventilation in combination with reduced occupancy of rooms are key factors to reduce the long-range transport of aerosols and shorten the associated transmission pathway, as demonstrated in tuberculosis transmission research.20,37 Furthermore, engineering controls to reduce the emission of dust should be extended as it is hypothesised that concurrent exposure to dust may affect exposure to COVID-19.

Adequate personal hygiene, including handwashing, will require that workers are well instructed and facilitated, and should be paired with cleaning procedures to provide frequent and adequate cleaning of surfaces, especially those that are frequently touched by different persons.38 Personal protective equipment which includes gloves, goggles, face shields, face masks, aprons, overalls, hair and shoe covers, and respiratory protection, will only be effective if workers are adequately trainedto use protective clothing and equipment, which includes instructions on how to correctly on, use/wear and off it.

The effectiveness of the facemask type of respirator, or the socalled disposable filtering facepiece (FFP), is very much determined by the ‘fit’, i.e. the presence or absence of facial leakages, rather than the filtration efficacy.39 In addition, it is quite often forgotten that ‘disposable’ implies replacement and not reuse. It will be interesting to determine whether adherence of viruses to dust particles will result in a Trojan horse effect if the particle size is close to the so-called most-penetrating particle sizes, which are in the range of 40 to 300 nm, depending on the filter material.40 As research indicates, appropriate donning practices very much determine the fit of respirators,41 and inappropriate doffing of respirators and gloves enhances crosscontamination. 15,42 Thus, the use of masks, i.e. non-medical masks for non-healthcare workers and the general public, must be accompanied by mask hygiene, and awareness and education.

OCCUPATIONAL HEALTH PREVENTION AND SURVEILLANCE

The general principles that play a major role in keeping workers healthy and safe, i.e. IDENTIFY, PREVENT, TRACE, TEST, TREAT, through early diagnosis, early treatment, and rehabilitation will also apply to the control of COVID-19, whilst maintaining workers’ dignity.

RECOMMENDED CONTROL AND CONTAINMENT

MEASURES FOR COVID-19 IN WORKPLACES

Since the onset of the COVID-19 outbreak, prevention and control have been major factors in curbing the rapidly-spreading virus. Therefore, current and credible information on the coronavirus and detailed protocols on planning and preparedness in the workplace for early detection, prompt isolation of contacts and suspected cases, and active surveillance, are essential.2,3,7,11,21 Employers should provide a safe and healthy workplace for employees, contractors and visitors, guided by the company’s occupational health and safety policy. The COVID-19 outbreak presents new risks to organisations and, thus, employers need to review their biorisk assessment strategies and compile risk management matrices for both health and safety, and business risks. Information and understanding of the likelihood and consequences of COVID-19 are needed to help refine risk assessments which will inform mitigation strategies within the work environment. This should include business continuity plans to cushion any economic or job losses. The implementation of necessary control measures should be tailor-made for various sectors, and risks should be communicated to all employees.8

Restrictions on employee travel (e.g. essential or emergency work) and monitoring thereof should be part of the mitigation plan. Occupational settings should consider having dedicated response teams that should remain in consultation with public health authorities for the early recognition and reporting of suspected COVID-19 cases.

All employees should be educated and alerted about the risk of COVID-19. Workers can be protected by good hand and respiratory hygiene practices and practising social distancing, and should not rely only on personal protective equipment (PPE).11 Employers should therefore make provisions for wash basins, hand sanitisers and PPE (as informed by the risk assessment), all of which should be readily available to all employees, visitors and contractors, as determined by policy.

Sick employees presenting with symptoms related to COVID-19 should be encouraged to stay at home. However, should they present at work, they should be separated from healthy workers. Ideally, a dedicated area should be identified by the employer for temporary isolation of suspected cases. If an employee is confirmed to have COVID-19, employers should inform fellow employees of possible workplace exposure, while maintaining confidentiality.

It is recommended that a tiered approach be followed to address primary, secondary and tertiary prevention measures. Naturally, the risks will be similar for some occupations, hence public and private employers and employees, trade unions and government should collaborate on preventive strategies for all concerned. The recommended approach is illustrated in Figure 1.

CHALLENGES

There are a number of challenges that hamper the containment and control of the COVID-19. Some of these are listed below:

  • There is a delay between disease development and progression, diagnosis and quarantine.12
  • Healthcare systems are strained, surveillance is inadequate, laboratory capacity is limited, public health human resources are scarce, and there are limited financial means to address these factors.
  • Multiple health challenges face the African continent, such as rapid population growth, increased movement of people, existing endemic diseases (eg. human immunodeficiency virus (HIV), tuberculosis, malaria), emerging and re-emerging diseases, and increasing incidence of non-communicable diseases.6
  • The main symptoms (fever, cough and shortness at breath) may not all be discernible at early stages of the disease, therefore a high level of clinical suspicion should be maintained to prevent disease transmission.16
  • There is no treatment, vaccine or pre-existing immunity to the virus.
  • Screening efforts may miss asymptomatic individuals who could transmit the virus.
  • A possible airborne mode of transmission is likely; however, insufficient scientific evidence is available.
  • Shortages of outbreak-related resources (e.g. PPE supply and/or universal masking) pose a challenge to workplaces globally, particularly in healthcare. Thus, interim measures for protecting workers must be put in place based on priority, i.e. imminent risk in the workplace, and available financial resources.
  • Lack of awareness leads to individuals presenting to ear, nose and throat (ENT) departments, thus overloading and increasing risk exposure to HCWs.
  • Contact tracing may miss certain individuals as the person under investigation (PUI) may not recall all contacts, or fear reporting them.
  • The biological agent classification for SARS-CoV-2 definition in the current regulation does not match the actual disease presentation.
  • Immune susceptibility varies among workers and, therefore, the risk profiles are different. In addition, workers do not disclose their underlying conditions, thus making it difficult to prioritise them.
  • Compliance to lockdown measures is problematic in some areas and occupational sectors (e.g. public transport and informal trade)

CONCLUSION

COVID-19 is now considered a global pandemic and the virus is spreading at an unprecedented rate. Given the challenges highlighted in this paper, it is crucial that scarce resources be appropriately allocated to prepare and respond effectively in a unified and co-ordinated manner across workplaces, countries and continents. Technical operations and testing must be impeccable and quality-assured, and collaboration and communication needs to be strengthened. The actions needed in the occupational health arena are fundamental and will contribute to the prevention of a social, health and economic tragedy. It is the responsibility of the employer to implement a preparedness plan for containing and controlling potential exposures, as well as to review its business continuity plans, in order to maintain a healthy, safe and sustainable workplace.

Source: Occupational Health South Africa : https://occhealth.co.za/pdf/Vol26No2MarchApril2020.pdf