Recently I attended the  CDC’s “Partner” webinar on Coronavirus COVID – 19 updates.

The concept that struck me the most was that the viral load is likely the highest in the throat and nasal passages at the very earliest signs of symptoms.

So those infected are most contagious at the pre-symptomatic or very early stages.

We also know that many people have been exposed with minimal or no symptoms may now be immune.

It may make sense to “allow” these folks to get back out into the world and workplace.

Many of my colleagues in urgent care and occupational medicine practice are fielding calls from their employer clients, especially in “essential” businesses, about how best to manage Covid 19 exposure and return to work decisions in their workplace.

Screening for COVID 19

The first step for any workforce should be a daily Covid 19 symptom screening routine.  Well established screening protocols have been published by CDC and other authorities.  Here is an example of a similar one we’ve developed for your potential use.

Even better, there is an app that companies can have workers perform their symptom check on their smartphone, tablet or computer every day before their shift, then get instructions about coming to work.  It works like this:

• Smart phone enabled COVID self assessment
  • Employees do this at home before coming to work
  • If + they stay home
  • If – they come in to work, get temperature screening
  • Employer/HR or Medical provider has a dashboard to see who screens + or -, who is going to next step, who needs testing
  • Schedule a demo here if interested in this
• If either above + perform Rapid test

No Touch Temperature Screening

Technology is now available that allows for AI assisted infrared camera screening of up to 30 individuals at a time, perfect for workplace entryways.

These systems can detect elevated body temperature within 0.6 degrees F from 10 feet away and displays results in less than one second.

And they’re surprising affordable for most businesses.

 Rapid Serologic Testing for Coronavirus Covid 19

Now that rapid serologic tests are becoming available for point of care testing, how should we incorporate this into our decision making process?

Much is unknown about the antibody response to this particular SARS CoV2 strain, but we know generally that IgM antibodies to viruses are detectable in the bloodstream a few days after exposure, followed in several more days to weeks by the appearance of IgG antibodies.

IgM antibodies thus indicate recently acquired infection or exposure, and IgG antibodies are generally associated with emergence of immunity.

One thing we don’t know, and won’t until much more time and research transpires, is the mere presence of IgG on a rapid test indicative of immunity?  All we know for sure is that it indicates some “longer” duration from time of exposure.  And that with most viruses IgG confers immunity.

But we also know when we perform “traditional” pre-placement serologic testing for Varicella, Measles, Mumps, Rubella, and HepB, we rely on the quantitative titer, a certain “threshold”, that has to be met, before we consider the individual to have immunity.

We may qualitatively be able to detect the presence of the antibody with a rapid test, but is that level of detection enough to surpass the required titer to confer immunity?  We don’t know.

FDA “Approval” for Rapid Serologic Covid 19 Tests

That is why there is no FDA Approval for these tests as diagnostic devices.  They are not “diagnostic.”  They are tools we can use along with our clinical judgement to arrive at a diagnosis and make educated determinations about infectivity and possible immunity.

Most companies developing these tests have applied for Emergency Use Authorization, but do fall under the March 16th, 2020 guidance from FDA (see FDA Rapid Test Kit Guidelines) about how to use and interpret the test.

The language that allows professional use only is meant to get these tools out to the medical community to assist with our decision making:

It’s important to note, however, that until the EUA is issued, these tests are by default considered CLIA high complexity.  FDA has said they will be CLIA waived once the EUA comes through, so you have to decide whether you are or want to be a high complex lab (I don’t recommend it) or wait until final approval.

How to Use Rapid Serologic Testing for Employees

Given that these tests then are a “tool” for clinicians to use along with individual patient risk factors, co-morbidities, job duties, symptoms, exposure and travel history, and given we have current CDC guidelines about returning to work after exposure or symptoms, a reasonable use of the rapid IgM/IgG tests might be:

Screening for Essential businesses:

• Test all employees, establish baseline for IgM/IgG
• Symptoms, fever or (+) IgM, indicates recent exposure/infection, isolate 14 days or 3 days after symptoms have resolved
• Consider re-test in a week or upon potential re-entry into workforce to determine if IgG appears
  • (+) IgG – return to work
  • (-) IgG – stay home, recheck in a week.  If still negative, use the 2 week/3 day guidance per CDC
• Re-test any employee that fails the daily symptom or temp check
• (+) IgG – use clinical judgement along with aforementioned additional criteria to determine possible immunity/convalescence and remain/return to workforce.
  • We can’t be sure if IgG level meets immune conferring titers
  • If individual had symptoms, now resolved and (+) IgG we may consider them recovered and return to work?
• Weekly testing of all (-)?  Consider on individual/company consultation basis

Of course as we learn more about serologic test results, immunity, re-infection (especially in those we have antibody results for previously), we’ll have more specific and validated testing and determination protocols.

And nothing here should be considered a recommendation of you must do– you must come to your own decisions as new information is available.

CLICK HERE for More information about Covid Test Kits

See the next article:  Temperature Screening for Return to Work During Coronavirus Pandemic