Ask the Rev. Doctor Maria
The Rev. Dr. Maria Evans is serving as the Interim Rector at Christ Church in Rolla. She is also a pathologist, board certified in Anatomic and Clinical Pathology, a laboratory medical director, and has served on hospital infection control committees for over 30 years.
During the coronavirus outbreak, The Rev. Dr. Maria is offering her expertise to help us understand and make our way through this unprecedented experience. If you have a question you'd like to ask The Rev. Dr. Maria, send an email to email@example.com.
Can an symptomatic individual who tested positive with a rapid test shed the virus? This individual was told they could have the virus in their system for a year.
I'm not sure in the question whether the person asking meant symptomatic or asymptomatic (that "an" in the question makes me wonder if they meant to start the next word with a vowel), but I'll try to answer in a way that covers both scenarios.
The short answer is "it depends." (There's an old medical joke out there that says the pathologist's favorite color is plaid, and I'm no exception to the rule in that joke!)
There's a big difference between "shedding viral particles" and "shedding viral particles capable of replicating." The most commonly used detection tests simply detect viral particles, whether they are capable of replicating or not. Determining that takes additional testing, and it's often neither medically expedient or temporally practical to justify the additional expense and delay. Generally, people are using the test to make a decision--whether to go back to work, allow contact with the family, etc. At this point, we know enough about the "typical" COVID case that we have some data to tell us info in the 95% confidence range that can save the expense of an additional test--so much so, the CDC has revised some of their guidelines for isolation and discharge of hospital patients. We're also learning more about the role of viral load (the number of viral RNA copies per millliter of blood) in COVID-19 infection. Here's what we know so far:
1. The typical person with a mild to moderate case of COVID-19 is infectious for up to 10 days after onset of symptoms. (In other words, they have virus capable of replication.) We are still a little unsure as to when an asymptomatic person becomes infectious from the point of exposure.
2. The typical person with a severe case of COVID-19 remains infectious for up to 20 days after onset of symptoms.
3. Here's where the point of confusion might lie. Recovered individuals can shed detectable virus up to 3 months from symptom onset; however, this appears to be below the threshold of viral load necessary for the virus to replicate. Our most educated call on this point is that it's leftover non-viable fragments from the previous infection.
This information is robust enough data that the CDC changed their recommendations from requiring 2 negative tests to return to work or other various activities (i.e., a test-based strategy) to instead using the above-mentioned timeframes as markers (a symptom-based strategy).
In full transparency, I was distrustful at first of the recommendation change in light of all we hear in the news about an alleged push to decrease testing coming from certain political figures, but CDC references the papers on which they based their rationale, and I've reviewed some of the references, and it appears to be legit data. I'm okay with these new guidelines; I don't think it's a politically motivated plot. Also, in other aspects of medicine, the normative way we use tests is to use them as a guide for patient management, not as the arbiter of patient management. There's a very old saw in medicine that goes, "You treat the patient, not the labs." Moving to this strategy is totally consistent with the way we manage other diseases.
This week, let's pray for all those who are having to make hard decisions in light of an increasing, yet still foggy, understanding of "who's infectious, who's not"--whether to return to work, put the kids in school, or take the safest trip possible to see loved ones.
The Rev. Dr. Maria Evans
who also doubles as
Maria L. Evans, MD, FCAP, FASCP
This material is not a substitute for professional medical advice or treatment. The Episcopal Church and its affiliates do not provide any healthcare services and, therefore, cannot guarantee any results or outcomes. Always seek the advice of a healthcare professional with any questions about your personal healthcare, including diet and exercise.