How Often Should You Test Your Workforce for COVID-19?

November 10, 2020

One of the primary challenges of the COVID-19 (COVID) pandemic is the isolation of individuals infected with SARS-CoV-2 (CoV-2), the virus that causes COVID, to prevent virus spread.  Over the course of the pandemic, we have learned the hallmark symptoms of COVID, such as coughing, shortness of breath and fever, and the importance of isolating ourselves from others if there is any chance we may be ill

Warehouse workers in facemasks

And while containment measures such as isolation and self-quarantining do reduce the spread of the virus, in reality, the CoV-2 virus isn’t this straightforward. Studies estimate that up to 40% of CoV-2-infected individuals remain asymptomatic for the duration of their infection, and individuals with asymptomatic COVID may be infectious, or capable of infecting someone else.1 Because quarantining employees that have COVID symptoms is not enough to contain CoV-2, organizations need to quickly and accurately test their workforce for infection in order to safely maintain operations during the pandemic.

Fast COVID testing is required to detect CoV-2-infected individuals and contain the CoV-2 virus before infected individuals are capable of spreading the virus to others. The CoV-2 virus has a relatively short incubation time: typically, it takes only five days between an individual’s time of infection to the development of symptoms,2 if the individual ever develops symptoms. Additionally, a CoV-2-infected individual becomes infectious about three days before symptoms start.3 These facts stress the importance of accurate, population-wide workforce testing with fast turnaround times, in order to detect and isolate COVID-positive employees at the earliest possible point in their infection cycle and contain potential outbreaks before they occur. Current COVID testing services can be expensive and slow, creating barriers for larger organizations that have large workforces to test. Thus, many larger organizations feel stuck between two impractical solutions: forego testing and risk ceasing operations or spend huge sums of money testing every employee every day hoping to detect and isolate infected employees before they become infectious.

Fortunately, there is a middle ground when it comes to organizational testing. One testing strategy, called sentinel testing, is designed to detect and monitor infection in a population by regularly testing a different random sample of the population. The advantages of this strategy, particularly for large business and university COVID testing, are significant, as random, consistent testing of a population not only identifies and isolates infected individuals, reducing the infection rate, but also determines the effectiveness of containment and mitigation strategies without the need to test every individual every day. For example, by testing just 17% of a workforce every five days for three months, the number of infected employees at a worksite can be reduced by up to 25%.4 Additionally, higher rates of testing, such as testing 40% of a small business workforce every three days over the course of three months can reduce the number of infected employees by up to 56%4 and provide a safe, practical means to maintain operations during the pandemic. The optimal testing frequency for an organization depends on a number of factors, including the total number of employees on site, infection rate goals, community COVID positivity rate, mitigation practices and public exposure level.

With all of the things that remain unknown during the pandemic, one point is clear: fast, accurate testing and basic virus mitigation strategies are our best tools for establishing and preserving a safe working environment before effective vaccines and therapeutics are available.  Additionally, regular workforce COVID testing increases workforce morale and productivity by providing employees the safest possible workplace. Kailos Genetics has developed an affordable, comprehensive and fully customizable COVID sentinel testing program, Assure SentinelTM, designed to allow workplaces to safely operate during the pandemic.  Click here to learn more about worksite screening or contact us with any questions you have about the program. Kailos understands the importance of certainty during the most uncertain of times.


1Centers for Disease Control. COVID-19 pandemic planning scenarios.

2Centers for Disease Control. Similarities and differences between flu and COVID-19.

3Kim Schive. How long before symptom onset is a person contagious?

4Kailos Genetics Internal Data. Data available upon request.