July 14, 2022 / Abby Roberts

Strategies for Work During a Pandemic

This post is based on Dr. Anthony Harris’ presentation at AIHce EXP 2021. It is the ninth in the “Essentials of Pandemic Response” series based on AIHA's 2021ebook.The mention of specific products or companies does not constitute endorsement by AIHA or SynergistNOW.

As the previous posts in this series have shown, preventing and managing COVID-19 in the workplace must be a significant concern for employers. Anthony Harris, MD, MBA, MPH, chief innovation officer and associate medical director at WorkCare Inc., said in May 2021 that COVID-19 could remain a threat to employee health and safety for at least the next five years. He noted that antigenic drift, the appearance of mutated forms of the virus, and antigenic shift, the appearance of a new virus strain, could cause case rates to again reach levels experienced during the first year of the pandemic. When these observations were made, antigenic drift had already occurred with SARS-CoV-2, significantly with the appearance of the more contagious Delta variant. In line with Dr. Harris’ predictions, the more transmissible Omicron variant would cause case rates during December 2021 and January 2022 to exceed levels seen at any earlier point in the pandemic. Dr. Harris stressed that prevention strategies will continue to be essential to reducing work-related exposure risk.

During his AIHce EXP 2021 presentation, titled “Implementation, Controls and Outcomes of a COVID-Free Protection Zone Model,” Dr. Harris described the COVID-Clear Zone model. This methodology is used by WorkCare clients to control exposure risk in workplaces where employees have the potential to come into close contact during their workday. The COVID-Clear Zone model features primary, secondary, and tertiary prevention strategies.

Primary prevention strategies occur before illness is present in a workplace. They involve monitoring and responding to leading indicators of workplace COVID-19 transmission risk. Secondary prevention identifies interventions that can be used to prevent employees from coming to work when they are contagious. Tertiary prevention deals with mitigating illness in the workplace, setting procedures for recovered employees to return to work, and maintaining business competitiveness and productivity.

Primary Prevention

Primary prevention leverages data to understand SARS-CoV-2 incidence and prevalence rates where businesses are located and takes steps to reduce the likelihood of employees becoming infected in the workplace. Dr. Harris provided several helpful resources for finding this data.

Johns Hopkins University’s Coronavirus Resource Center features an interactive map that displays U.S. COVID-19 data by county. Users can generate a COVID-19 status report individually for each county, making this map a helpful tool to understand local community transmission risk and develop an organizational COVID-19 control strategy.

COVID-19 seropositivity rates are another form of data that can be used by health and safety professionals to understand local transmission risk and develop prevention strategies. CDC researchers collaborate with commercial laboratories and blood collection centers to estimate U.S. seroprevalence rates: that is, the percentage of people across the country who have been infected with SARS-CoV-2 and carry antibodies to the virus. In some cases, people do not experience symptoms and are unaware that they have SARS-CoV-2 infection. When people donate blood or undergo blood testing for reasons unrelated to COVID-19, additional tests can be used to determine whether they have SARS-CoV-2 antibodies.

Global COVID-19 macro trends may be used to forecast how transmission rates might change at the local level, particularly with respect to SARS-CoV-2 variants, even when an outbreak is occurring in another country.

According to Dr. Harris, primary prevention strategies follow industrial hygienists’ familiar hierarchy of controls, particularly relying on the use of engineering and administrative controls. Common COVID-19 engineering controls include physical barriers to reduce person-to-person transmission of infectious respiratory droplets (however, since the time of this presentation, concerns have been raised that these barriers restrict airflow). Common administrative controls include remote work and schedules that limit the number of people in the workplace at a given time. It may be possible to substitute work-related activities more likely to result in employee exposure to the virus with those less likely to result in exposure.

Secondary Prevention

Secondary COVID-Clear Zone strategies are used to identify employees who may be infected and prevent them from transmitting their illness to others. Dr. Harris associates these strategies with the elimination level of the hierarchy of controls.

“You want to eliminate the hazard,” Dr. Harris said. “In this case, the hazard is the vector of the individual who is sick. Keeping them at home safely has been very effective to help prevent workplace transmissions since the pandemic has begun.”

Dr. Harris’ recommended implementation strategy for COVID-19 screening begins with baseline testing, which uses PCR or antigen tests to monitor every employee for current or past SARS-CoV-2 infection, including asymptomatic infections, before they enter the workplace. This approach can be used in tandem with symptom screening, which identifies employees with current symptoms. Subsequent tests can be compared to baseline results. When there are changes in status compared to baseline, the results can be used to stratify or triage employees into high-, medium-, and low-risk categories. Criteria for risk appraisals may include demographic and behavioral risk factors, such as employees’ ability to practice social distancing outside of work and the presence of infected household members. For employees with high risk, the COVID-Clear Zone strategy institutes scheduled testing and COVID-19 case management to monitor employees’ diagnoses and symptom progression and chart their return to work.

Organizations may have to allocate resources for testing depending on the nature of their business (for example, essential production or services), their location, and community or regional incidence rates. A health and safety professional can create a heat map of facility locations identifying those with the greatest need for testing resources.

Dr. Harris’ secondary COVID-19 prevention strategy also incorporates the selection of screening tools. Since the beginning of the pandemic, many testing products have become available. Health and safety professionals may be charged with selecting the best testing tool and testing frequency for the circumstances in the context of workplace case rates and external environmental triggers, such as local COVID-19 incidence rates.

Dr. Harris recommended testing as frequently as feasible. Organizations may consider pool-testing methodologies, in which test samples from a small group of employees are collected and combined for testing. If a positive result is produced, then members of that pool are tested again rather than an entire population of employees. Dr. Harris also recommended implementing workplace contact tracing to identify employees who may have been exposed to the virus, which may be accomplished using web application-based technologies.

Tertiary Prevention

Tertiary prevention strategies help mitigate absenteeism and guide employees’ return to work after illness. According to Dr. Harris, the process includes clinician review of the history and duration of an employee’s exposure and whether quarantine is necessary; the onset, duration, and severity of the employee’s illness; and the duration of leave from work required to prevent transmission, which may take into account the employee’s job duties, ability to practice social distancing at work, and the availability of personal protective equipment.

Return-to-work algorithms may be used for high-level use cases. Dr. Harris has developed protocols for employees who are presumed or confirmed positive for COVID-19 and those who have been exposed to a household or community member positive for COVID-19. Return-to-work algorithms are also applied to employees with low-risk symptoms consistent with the common cold or flu-like illnesses. Algorithms provide a decision-making framework for circumstances that trigger an employee’s return to work, such as the duration of quarantine, duration of time since symptoms resolved, and the receipt of positive or negative lab tests.

It may also be necessary to develop return-to-work policies for employees who have contracted and recovered from COVID-19 and are not infectious but have lingering health effects, which may be referred to as “long COVID.” Dr. Harris cited CDC findings that one in five adults have not returned to their previous state of health up to three weeks after testing positive for COVID-19. “If we move forward with the assumption that workers may have even six months’ worth of symptoms,” Dr. Harris continued, “we have to have measures in place to help protect them in the workplace and keep workplaces safe overall.”

One potential long-term health effect associated with COVID-19 illness is cognitive decline, also known as “brain fog.” For months after recovery, employees of any age may display forgetfulness, find it difficult to perform work tasks or to prioritize and plan, feel sleepy, or have symptoms of anxiety. This has implications for workplace safety. Dr. Harris suggested that employers mitigate the effects of brain fog by conducting neuropsychological surveys and testing during the return-to-work process. In April 2021, a team of neurologists at Columbia University published a review of the literature existing at that point on neurological symptoms of COVID-19.

Dr. Harris noted that employee mental health is impacted by the pandemic in several ways and for a variety of underlying reasons. For example, work demands and exposure risk associated with the pandemic may result in symptoms of post-traumatic stress disorder (PTSD). Crisis response also affects workforce productivity: in response to COVID-19, many businesses experienced an initial period of disarray and confusion, then a rise in productivity as decisions were made and people rallied in response, followed by a second drop in productivity as fatigue set in, and finally a slow recovery back to baseline. Dr. Harris recommended implementing mental health screening and triage similar to the secondary prevention strategies employed for physical illness.

Overall, return-to-work policies should address the relative risk of SARS-CoV-2 transmission in the workplace. “It’s important to understand the level of exposure risk and the degree of conservatism [that is, caution regarding mitigation and prevention measures] that should be applied to the deployment of these strategies,” Dr. Harris said. In his model, a less conservative approach includes daily symptom screening, use of face coverings, social distancing, and hand hygiene. A moderate approach implements those measures as well as contact tracing, voluntary testing, and vaccination verification tracking. The most conservative approach in his model adds mandatory testing and surveillance of every employee.

For more information, Dr. Harris also presents a free monthly webinar series covering COVID-19 and occupational health trends, which is accessible on YouTube.


Harris, Anthony: “Implementation, Controls, and Outcomes of COVID-Free Protection Zone Model,” AIHce EXP Virtual Conference Presentation (May 25, 2021).

Abby Roberts

Abby Roberts is the editorial assistant for The Synergist.


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