To my Patients and Friends,
Hi there, everyone… COVID-19 testing and contact tracing efforts have been in the news ad nauseam these days, so I thought I’d share some insights.
The latest on COVID-19 antibody testing
Do you recall having an illness some time over the course of this past winter that, in retrospect, may have been COVID-19? Many patients have asked about how to go about getting antibody tests to determine if they have previously been exposed to the virus and are therefore immune from reinfection.
First, a primer.
Early in the course of a viral infection, the body mounts a coordinated immune response involving different types of white blood cells (WBCs), which are those cells that comprise the bulk of the body’s defense system. Certain WBCs, called plasma cells (or B cells), produce Y-shaped proteins (antibodies) in response to the presence of a specific viral surface antigen. In attaching themselves to the viral particle, they mark it for destruction via a complex cascade of immune responses by other types of WBCs. There are actually several types of antibodies, or immunoglobulins, all of which serve a particular function… but the two that matter here are the IgM and IgG antibodies. IgM antibodies appear after the first few days of infection and participate in the early phase of the body’s immune response. Shortly thereafter, usually within several weeks, IgG antibodies appear on the scene. These antibodies, which are specific to a particular antigen, tend to persist in the bloodstream indefinitely and typically indicate immunity to the corresponding virus.
The COVID-19 antibody tests that are being discussed seek the presence of both IgM and IgG antibodies. And it really would be nice to have access to these tests ASAP in order to begin contemplating a new normal. I dug into this in some detail in my last newsletter. The antibody test panel may not be very practical for diagnostic purposes, as IgM antibodies will generally not appear for several days after the onset of an infection, as discussed above. However, IgG is all the rage. Understandably, we all want to know if we’ve produced these antibodies in response to a prior exposure which, in theory, may indicate that we are immune to a repeat COVID-19 infection. However, some important caveats warrant consideration:
- Although there is good reason to be hopeful, research to date has not clarified if (or for how long) individuals may remain immune to a repeat infection after an initial exposure to this particular coronavirus (SARS-C0V-2)
- We can only speculate at this stage as to whether or not the presence of IgG antibodies is a reliable indicator of robust or sustained (versus mild or transient) immunity; we still don’t know for sure
- The accuracy of these tests will not be 100%; there are concerns about false positives as well as false negatives
- The presence of IgG antibodies does not in and of itself exclude the possibility that someone may still be contagious; current PCR testing and symptom monitoring will still play crucial roles
- Not all of these tests have been FDA-approved
- There can be cross-reactivity between other coronaviruses that are associated with the common cold and the one associated with COVID-19; accuracy is a concern for this reason as well
- Supply chains have not caught up with demand. It will take some weeks for these tests to be readily available to us all
Rest assured, we will have answers to these questions as this testing modality evolves, but it will take a little bit more time… stay tuned.
Emerging alternative testing methods
Saliva testing has arrived on the scene. Time will tell how effectively we’ll be able to scale up this type of testing in order to meet the needs of the general public. We will also need to continue studying it to ensure that it provides accurate results. It certainly represents an easier, less invasive alternative to the traditional PCR testing which involves nasal and or throat swabs.
This process, wherein contacts of those who have been infected with the coronavirus are tracked and notified of the potential need to self quarantine and self-monitor, will play a vital role in our recovery, both here and abroad. Normally, contact tracing is an onerous, time-consuming process which requires a robust communications system and the assistance of an army of public health personnel. However, in the age of COVID-19, information technology (IT)- based contact tracing alternatives are under active discussion (also reviewed in a previous newsletter) and will likely play a pivotal role vis-à-vis the COVID-19 pandemic (and all future pandemics). As we strive to reopen the economy and pursue a new normal, the entire U.S. will need to engage in some form of rigorous contact tracing; such efforts are already underway here in Connecticut. But, in the context of this pandemic, IT-based methods- whether via GPS tracking, or smart phone tracing applications, or QR code scanning when entering buildings or public transport facilities, or some combination thereof- will be vital. This very interesting article discusses how the use of IT-based contact tracing enabled Asian countries like South Korea to meaningfully impact the trajectory of the COVID-19 pandemic in those regions. Another article also delves deeply in an attempt to address questions related to technology and infrastructure; both articles acknowledge some of the potential cultural pitfalls that we may encounter here in the U.S., particularly as related to matters of privacy and government oversight.
In my opinion, if we are to get ahead of COVID-19 in the foreseeable future (and to have any hope of warding off future pandemics), we’ll need to accept this potentially intrusive but necessary evil as part of our new normal.
Bumps in the road
We are all links in the same worldwide chain. If we can’t agree on some key unassailable principles for successful containment of COVID-19, then the light at the end of this long tunnel will move ever more distant. All individuals, all leaders, all organizations and businesses and municipalities and states and nations need to recognize facts and science, to value expertise, to be willing to acknowledge and learn from our mistakes, to look to the experiences of others, to prioritize the public good over private agendas, to accept that this will take longer than any of us would like, and to recognize that we are all in this together. And we’re not there right now.
Smaller elephants still in the room
Children may be late for their routine measles (and other) vaccines with our current emphasis on minimizing the spread of COVID-19. Medical practices should be tracking these cases so that children can get back on track with vaccination schedules as soon as possible. That said, it would be prudent for you all to keep track of your families’ vaccine schedules as well.
A shout-out to a kind New Canaanite
This is how it’s done. Kudos to people like Neen!
That’s all for today… stay safe and continue to look out for each other. See you soon!