Testing Strategy for Coronavirus (COVID-19) in High-Density Critical Infrastructure Workplaces after a COVID-19 Case Is Identified

Workers in critical infrastructure sectors could also be permitted to work if asymptomatic after potential exposure to a confirmed case of coronavirus disease 2019 (COVID-19), offered that employee an infection prevention suggestions and controls are applied. Outbreaks of sickness amongst staff in food-producing services and surrounding communities have raised distinctive questions that recognized the necessity for testing for COVID-19 to complement present steerage. This doc presents totally different testing technique choices for uncovered co-workers when public well being organizations and employers decide testing is required to assist help present illness management measures. Such methods can assist in figuring out infectious people with the purpose of decreasing transmission of SARS-CoV-2 within the office. These methods increase and don’t exchange present steerage.

SARS-CoV-2, the virus that causes COVID-19, is primarily unfold from individual to individual by means of respiratory droplets. Workers in high-density settings during which staff are within the office for very long time intervals (e.g., for 8-12 hours per shift), and have extended shut contact (inside 6 toes for 15 minutes or extra) with coworkers could also be at elevated danger for publicity to SARS-CoV-2. An in depth contact is outlined in present Public Health Recommendations for Community-Related Exposure. Other distinctive components which will enhance danger for transmission amongst these staff embrace: sharing transportation reminiscent of ride-share vans or shuttle automobiles, car-pools, and public transportation; frequent contact with fellow staff in neighborhood settings in areas the place there may be ongoing neighborhood transmission; and shared or congregate housing reminiscent of dormitories. Workers embrace, however are usually not restricted to, all workers, contractors, and others who carry out work on the facility or worksite. Early expertise from COVID-19 outbreaks in quite a lot of settings means that when symptomatic staff with COVID-19 are recognized, there are sometimes asymptomatic or pre-symptomatic staff with SARS-CoV-2 current on the office. Testing is essential to determine such people, as they might not know they’re contaminated. SARS-CoV-2 transmission from asymptomatic or pre-symptomatic individuals can lead to further circumstances and probably outbreaks of COVID-19. Implementing screening for signs of COVID-19, testing, and contact tracingpdf icon could also be used to detect contaminated staff earlier and exclude them from the office, thus stopping illness transmission and subsequent outbreaks.[13]

Critical infrastructure employers have an obligation to handle the continuation of labor in a manner that greatest protects the well being of their staff and most people. Appropriate office protections, reminiscent of engineering and administrative controls, for these current within the office ought to stay in place. Examples of those controls may be present in present steerage for Meat and Poultry Processing Workers and Employers, and for Manufacturing Workers and Employers and other critical infrastructure guidancepdf iconexternal icon. Screening1 staff and others getting into the office for signs of COVID-19 and physique temperature is a crucial element of stopping transmission and defending staff. Workplaces ought to evaluate and observe present guidance. Workers who’re symptomatic upon arrival at work, or who turn into sick in the course of the day, ought to instantly be separated from others. They needs to be despatched to their residence or a well being care facility, as applicable, and referred for additional analysis and testing in session with the state, territorial, or native well being departments or by means of occupational well being suppliers.

After a COVID-19 case is recognized, testing methods of uncovered co-workers could also be thought of to assist forestall illness unfold, to determine the scope and magnitude of SARS-CoV-2 an infection, and to tell further prevention and management efforts that is likely to be wanted.

Viral (nucleic acid or antigen) testing needs to be used to diagnose acute an infection.

Two sorts of checks can be found for COVID-19: (1) viral tests to detect present infections, and (2) antibody tests to determine earlier infections. CDC gives an overview of classes of individuals for SARS-CoV-2 testing with viral checks (i.e., nucleic acid or antigen checks). Viral testing can be utilized to tell actions essential to maintain SARS-CoV-2 out of the office, detect COVID-19 circumstances rapidly, and cease transmission. Testing practices ought to purpose for speedy turnaround instances as a way to facilitate efficient motion. Viral testing detects an infection on the time the pattern is collected; very early an infection on the time of pattern assortment or publicity (e.g., office or neighborhood) after pattern assortment can lead to undetected an infection. Testing at totally different time limits, additionally known as serial testing, could also be extra more likely to detect acute an infection amongst staff with repeat exposures than testing accomplished at a single cut-off date.

At the present time, antibody test outcomes shouldn’t be used to diagnose somebody with an energetic SARS-CoV-2 an infection. Refer to the CDC web site for extra info concerning testing for COVID-19 and specimen collection.

Considerations to be used of a testing technique for COVID-19 an infection:

  1. A testing technique ought to solely be applied if outcomes will result in particular actions.
    • When a confirmed case of COVID-19 is recognized, interviewing and testing probably uncovered co-workers ought to happen as quickly as potential to scale back the chance of additional office transmission.
  2. A complete strategy to decreasing transmission is beneficial. Positive check outcomes point out the necessity for exclusion from work and isolation at home.
    • When staff are living in close quarters, reminiscent of individuals who share a small residence, or individuals who dwell in the identical family with giant or prolonged households with ongoing danger of shut contact exposures to COVID-19, various housing could also be thought of.
    • Decisions about whether or not staff with COVID-19 needs to be directed to alternate housing websites needs to be made in coordination with native or state public well being authorities. Discontinuation of isolation for individuals with COVID-19 and work exclusions might observe both a symptom-based strategy or test-based technique in session with a healthcare supplier.
  3. A risk-based strategy to testing co-workers of an individual with confirmed COVID-19 could also be utilized. Such an strategy ought to take into accounts the chance of publicity, which is affected by the traits of the office and the outcomes of contact investigations (see Figurepdf icon). Examining facility and operations work information, conducting walk-throughs, and worker interviews might assist in categorizing co-workers into the three tiers of testing precedence. Prioritization needs to be accomplished rapidly in order that testing of colleagues will not be delayed. Additionally, if ongoing screening for symptomatic staff or contact tracing identifies further staff who check constructive, the algorithm outlined beneath needs to be utilized to their contactspdf icon.
    • Tier 1 is the best precedence for testing of uncovered co-workers. Because people with COVID-19 could also be infectious previous to symptom onset [2,4], contact tracing and baseline testing ought to embrace co-workers who have been uncovered to a employee with confirmed COVID-19, starting 2 days earlier than the person with COVID-19 turned symptomatic (or, for asymptomatic staff, 2 days previous to specimen assortment) till the time of isolation. Exposure consists of:
      1. Those who’re recognized as shut contacts by means of case investigation and contact tracingpdf icon evaluating proximity and size of contact of colleagues with the person with COVID-19. If the choice is made to check all co-workers in the identical space on the identical shift, then contact tracing can simply give attention to different potential shut contacts, for instance those that particularly point out consuming lunch collectively, coworkers who carpool, or reside in the identical residence.
      2. Co-workers who work throughout the identical shift or overlapping shifts, in the identical space, for instance on the identical line and similar room, as a number of of the employees with COVID-19 primarily based on the employer’s evaluation of danger within the office, such because the structure and dimension of the room, the design and implementation of engineering controls, adherence to administrative controls2, and motion of staff inside the space.
    • Tier 2 is the following highest precedence tier for testing. Tier 2 consists of staff on the identical shift, however in a unique space of the ability or operation who might have had an publicity to a employee with confirmed COVID-19. Testing could also be prolonged to staff in Tier 2 primarily based on outcomes from contact tracing or primarily based on the employer’s evaluation of danger within the office. If further COVID-19 circumstances are recognized, then reassessment of the tier and testing could be indicated. Some services and workplaces might concurrently implement Tier 1 and Tier 2 testing. This would come with testing all uncovered staff on the identical shift because the employee(s) with confirmed COVID-19, no matter space of the ability.
    • Tier Three consists of staff not in Tiers 1 or 2. Tier Three consists of staff who shared a typical area (e.g. a bathroom, break room) and subsequently publicity to employee(s) with confirmed COVID-19 can’t be definitively dominated out. Tier Three additionally consists of staff who usually work a unique shift than the employee(s) with confirmed COVID-19 however publicity can’t be excluded primarily based on the potential for overlap in work time from back-to-back shifts. Testing could also be prolonged to staff in Tier Three primarily based on contact tracing or on the employer’s concern about total danger of COVID-19 within the office. Some services and workplaces might elect to incorporate testing of colleagues in Tier Three from the outset. For instance, excessive charges of COVID-19 transmission within the surrounding neighborhood might immediate employers to check extra broadly. Note that if check outcomes from Tier 1 or Tier 2 testing point out an infection amongst staff in a number of areas of the ability, together with some circumstances amongst staff who labored on a number of shifts, then testing might should be expanded accordingly.
  4. Implementation of testing methods can complement measures to scale back transmission within the office, provided other protections are in place to guard employee well being whereas protecting the office open. If employers elect to conduct facility-wide testing, a number of asymptomatic staff with SARS-CoV-2 an infection could also be recognized. Employers ought to have a plan for assembly staffing wants whereas these individuals are out of the office per COVID-19 Critical Infrastructure Sector Response Planning. Of notice, CDC’s critical infrastructure guidance gives exceptions to present residence quarantine practices after an publicity to COVID-19. Current steerage advises that employers might allow staff who’ve had an publicity to COVID-19, however who would not have signs, to proceed to work, offered they adhere to further security precautions, reminiscent of measuring the worker’s temperature and assessing for signs of COVID-19 earlier than every work shift (“pre-screening”), asking the worker to self-monitor for signs throughout their work shift, and asking the worker to put on a fabric face overlaying whereas they’re within the office. A testing technique ought to improve present illness prevention measures by augmenting skill to detect an infection amongst asymptomatic or pre-symptomatic staff. For all these methods, ready for check outcomes previous to returning to work is most well-liked to maintain contaminated staff out of the office.
    • Workers in Tier 1, who’ve shut contact with or publicity to a co-worker with confirmed COVID-19 needs to be examined and quarantined as quickly as potential to scale back the chance of additional office transmission. Workers ought to observe present guidance concerning self-monitoring by checking their temperature twice every day and looking forward to signs. Strategies with differing ranges of danger of office transmission could also be thought of for uncovered however asymptomatic crucial infrastructure staff in Tier 1 to return to work with applicable office protections. Strategies involving serial testing (e.g., testing at baseline and Day Three vs. testing solely at baseline) usually tend to determine contaminated staff than testing at a single cut-off date. In deciding on a method, employers ought to think about which technique appropriately balances sustaining operations with employee security. Strategy Three ought to solely be thought of throughout crucial staffing shortages.
      • Strategy 1: The technique is for uncovered staff in Tier 1 to observe present suggestions concerning exclusion from work. These staff are excluded from work and quarantined for 14 days, primarily based upon the incubation interval, even when their baseline check outcomes are damaging. This technique reliably excludes staff who’re uncovered and will turn into contaminated, limiting an infection of others within the office.
      • Strategy 2: The technique is a test-based possibility for returning to work sooner than 14 days after an publicity for staff in Tier 1. This consists of baseline testing and serial testing (i.e. re-testing) each Three days till there are not any extra new circumstances detected within the Tier 1 cohort. Individual staff in Tier 1 who stay asymptomatic and have damaging checks at baseline and Day Three can return to work and will proceed to be examined each Three days after returning to work till there are not any extra new circumstances within the employee cohort. With this technique some staff who’re contaminated and return to work might start to shed virus after Day 3. Infection in these staff might be missed with out serial testing leading to potential office transmission. Workers who check constructive or turn into symptomatic throughout quarantine or after getting back from work needs to be excluded from the office, as mentioned above.
      • Strategy 3: During crucial staffing shortages, one other technique to facilitate early return to work is to permit asymptomatic staff in Tier 1 to return to work after a baseline check is obtained. Under this technique, it’s endorsed that return to work would observe a damaging check consequence, however might happen whereas outcomes have been pending, offered different protections are in place. In this case, this employee cohort ought to proceed to be examined each Three days after returning to work till there are not any extra new circumstances. Workers who check constructive or turn into symptomatic needs to be excluded from the office, as mentioned above.
    • Workers in Tier 2 and Tier 3: Screening for signs ought to proceed for staff in Tiers 2 and three. Baseline testing could also be thought of for these staff primarily based on the employer’s evaluation of publicity danger within the office or a constructive symptom display. They can proceed to work offered they continue to be asymptomatic and, if examined, their check is damaging.
  5. Which organizations carry out the testing might fluctuate amongst jurisdictions and will embrace the general public well being division, an worker well being clinic, a healthcare supplier engaged by the employer, or native well being care services.
    • Symptom screening, testing, and speak to tracing should be carried out in a manner that protects confidentiality and privateness, to the extent potential, and is according to relevant legal guidelines and laws. To forestall stigma and discrimination within the office, make worker well being screenings as personal as potential. Follow steerage from the Equal Employment Opportunity Commissionexternal icon concerning confidentiality of medical information from well being checks.
      Symptom screening upon entry to the office needs to be designed in order that the screening course of is performed in as personal a fashion as potential, with out a employee’s private info being overheard or communicated inappropriately at any time. Because OSHA’s Access to Employee Exposure and Medical Records normal (29 CFR § 1910.1020external icon) requires that lined employers retain medical information at some stage in employment plus 30 years, think about the burdens and advantages of documenting individually identifiable outcomes of entry screenings. Healthcare suppliers which might be covered entitiesexternal icon below the Health Insurance Portability and Accountability Act (HIPAA) should abide by HIPAA guidelines. Due to the “direct threatexternal icon” posed by COVID-19 to co-workers, healthcare suppliers who check staff for COVID-19 as described on this steerage ought to notify employers of examined staff’ health for obligation, office restrictions (e.g., restrictions on skill to enter the worksite, limitation to telework, and so forth.), and the necessity for contact tracing of different staff deemed to be in shut contact, even when this would possibly enable employers to surmise that workers may need COVID-19. However, suppliers shouldn’t share workers’ check outcomes or diagnoses with employers with out workers’ permission, despite the fact that at entry screening, employers may ask all employees who will be physically entering the workplace if they have COVID-19external icon, or signs related to COVID-19, or ask if they’ve been examined for SARS-CoV-2.
    • Providers ought to report and clarify check outcomes to staff and notify the state, territorial, tribal, or native well being division of circumstances in a well timed trend. When employers turn into conscious of circumstances, the Recording and Reporting Occupational Injuries and Illnesses normal (29 CFR part 1904external icon), might require sure employers to maintain a record of serious work related injuries and illnessesexternal icon together with work related COVID-19external icon.
    • Contact tracing, whether or not carried out by a well being division or a healthcare supplier engaged by the employer, needs to be carried out in a manner that protects the confidentiality and privateness of an worker with COVID-19, or a SARS-CoV-2 constructive check, to the diploma potential.
  6. Ensure that sick go away insurance policies are versatile and according to public health guidance and that workers are conscious of and perceive these insurance policies. Maintain versatile insurance policies that let workers to remain residence to look after a sick member of the family or deal with kids resulting from college and childcare closures. Additional flexibilities would possibly embrace giving advances on future sick go away and permitting workers to donate sick go away to one another. Employers that don’t at present supply sick go away to some or all of their workers ought to think about drafting non-punitive “emergency sick leave” insurance policies.


1Employers ought to consider the burdens and advantages of recording staff’ temperatures or asking them to finish written questionnaires.  These forms of written merchandise can turn into information that should be retained at some stage in the employees’ employment plus 30 years. See OSHA’s Access to Employee Exposure and Medical Records normal (29 CFR § 1910.1020).

2At this time, differential willpower of shut contact for these utilizing cloth face coverings will not be beneficial per CDC guidancepdf icon.


  1. Treibel, T.A., et al., COVID-19: PCR screening of asymptomatic health-care staff at London hospital. The Lancet, 2020. 395(10237): p. 1608-1610.
  2. Dora, A.V., et al., Universal and Serial Laboratory Testing for SARS-CoV-2 at a Long-Term Care Skilled Nursing Facility for Veterans – Los Angeles, California, 2020. MMWR Morb Mortal Wkly Rep, 2020. 69(21): p. 651-655.
  3. Moriarty, L.F., et al., Public Health Responses to COVID-19 Outbreaks on Cruise Ships – Worldwide, February-March 2020. MMWR Morb Mortal Wkly Rep, 2020. 69(12): p. 347-352.
  4. He, X., et al., Temporal dynamics in viral shedding and transmissibility of COVID-19. Nat Med, 2020.

Note:  This doc is meant to supply steerage on the suitable use of testing and doesn’t dictate the willpower of fee choices or insurance coverage protection of such testing, besides as could also be in any other case referenced (or prescribed) by one other entity or federal or state company.

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