SARS-CoV-2 Reinfection: Bad News, or Good?

Our disparate inclinations famously refract the same view into opposing perceptions: a glass half full, or half empty. The anxious passions engendered by the COVID19 pandemic have greatly amplified that proclivity. Rarely has the gulf between competing versions of optimism and pessimism, or other reciprocal ideologies, yawned so great.
A glass of water on a white background: half full or half empty

Perhaps that’s why I have found these past months so dysequilibrating. As a pragmatist, in the middle, there is not much under me, not much company around me. The glass is the glass. My predilection is to wonder: was I thirsty to begin with? Is it cold? Is there a tap nearby in case I want more? Ice is nice to have, but not need to have.

Viewing COVID in much that way, I welcome the news about the first confirmed case of re-infection as far more good than bad for reasons owing nothing to optimism, and much to pragmatism.

You have doubtless heard: there has indeed now been one confirmed case of reinfection with SARS-CoV-2, the viral agent of the COVID pandemic. This news has likely reached you via blaring headlines, wrapped in the standard measure of media drama. Chances are good the news as delivered, or perceived, skewed bad.

Every way I look at it, however, I see good news.

First, this is the first confirmed case of reinfection, meaning everything you have heard about reinfection up until now was error, conjecture, or hype. That there has thus far been just one reliably confirmed re-infection (yes, there will be others) among the world’s almost 24 million documented cases (to say nothing of the many, many tens of millions more undocumented cases) tells us not that this is a grave threat, but that it is – in the short term at least – a quite uncommon occurrence.

More importantly, this case of re-infection did not occur in someone sheltering in place- or even staying in his country. It occurred when someone who had the virus early in the pandemic in Hong Kong traveled to several countries in Europe, in the midst of relatively high-level transmission there of a different strain of the virus, some months later. This is a pretty precise set of circumstances ideally configured to favor re-infection.

And, most important of all: this individual had mild symptoms with the initial infection, and no symptoms at all when re-infected. (In case you are wondering why someone without symptoms was tested at all, it was a routine check at an airport following travel to Spain, via the U.K.) This strongly suggests just what we would hope: immunity diminishes, but does not disappear. Even though the second infection was with a different strain of the virus, immunity acquired from the initial encounter appears to have made the very difference we would hope for: a reduction in severity.

This is common with many infections. Immunity is not a yes/no, all-or-nothing phenomenon, despite the media tendency to treat it as such; it always comes in shades of gray. It is possible, after enough time or with changes in health, to get varicella (the chickenpox) twice; it is possible to get measles twice. However, these are uncommon occurrences, because they will only happen when there is a significant exposure that coincides with a nadir in immunity. There is every reason to expect some variant on this theme with SARS-CoV-2, so it should come as no surprise that re-infection after months is possible. The phenomenon of waning immunity over time is the very reason for every “booster” vaccine you have ever heard of or received.

Were re-infection common, in the same place, with the same strain of the virus – that would be concerning. If re-infection were as bad or worse than the original infection- that would be worrisome. But if re-infection occurs with a different strain of the virus, after an interval of months, and is milder than the original- that ticks off every box I have for “best case scenario.”

A final comment is that the individual in question had such a mild case the first time around that he never made discernible antibodies. His second illness, with a different viral strain, was milder than the first even so- suggesting that even absent measurable antibodies, a prior infection nearly 5 months earlier was still conferring protection. More significant illness correlates with detectable antibodies, and almost certainly equates to more robust immunity.

The bottom line: we “finally” do have actual news of re-infection with SARS-CoV-2. Apply a lens not distorted by drama, dogma, or fixed ideology- and the news looks to be good.

So, catch your breath, and if you’re thirsty- take a drink. There is, indeed, a tap nearby.


Dr. David L. Katz is a board-certified specialist in Preventive Medicine/Public Health.

This article was first published on LinkedIn.

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