You know those synthetic antibodies like Trump got? They’re not a vaccine.

By now, many of you are aware that Donald Trump received a rather impressive drug “stack” consisting of synthetic (“man-made”) monoclonal antibodies, dexamethasone and remdesivir as part of his treatment for Covid. Chris Christie reportedly also received synthetic antibodies.

This got me thinking: Might Trump and Christie be at risk of re-infection by SARS-CoV-2, the virus that causes Covid-19, once the synthetic antibodies wear off? What would this mean for the rest of us?

The Negative Feedback Effect (No, not that one.)

In medicine, there’s something known as the negative feedback effect. No, I’m not talking about when you get upset because someone criticizes you on social media. An example of the negative feedback effect that I’m referring to occurs when people are given steroid hormones. For instance, when bodybuilders and athletes take anabolic steroids -essentially, synthetic versions of testosterone- this suppresses their natural (a.k.a. “endogenous”) testosterone production.

This made me wonder: Could a similar effect occur with synthetic antibodies?

The ”What if?”

What if, by administering Covid-fighting antibodies to a patient, it prevents their immune system from producing its own (endogenous) antibodies, thereby leaving them unprotected against re-infection by SARS-CoV-2 once the level of the synthetic antibodies inside their body has returned to baseline (i.e. zero), as it eventually must?

“Wait, why is this relevant to me?”

It’s relevant to because pre-Covid life with the flu vaccine and life with a Covid vaccine will be two different ball games until we have broadly effective treatments to serve as a backstop. Currently, we don’t. If treatment with synthetic antibodies helps patients recover but leaves them vulnerable to re-infection just as they were pre-treatment, that’s something we need to know, pronto.

Dexamethasone, while inexpensive, is generally effective in severe cases of Covid when there’s a lot of inflammation. That leaves remdesivir and the synthetic antibodies like those given to Trump and Christie. So far at least, remdesivir doesn’t seem to be as effective as hoped. (I think the recent FDA approval was rushed and unjustified, based on the available evidence.). The scientific jury is still very much out on synthetic antibodies. They’re considered experimental at this point.

I asked scientists.

In search of answers, I reached out to several scientists in academia with expertise in related fields of study to ask if they were aware of any evidence for or against an antibody-induced negative feedback effect. As I type this, I’ve had three responses, all essentially saying “We don’t know”, but two of them acknowledging that it may indeed occur.

The first answer came from Dr. Michael Kinch (PhD). He’s a Professor of Biochemistry & Molecular Biophysics and the Director of the Centers for Research Innovation & Biotechnology & Drug Discovery at Washington University in St. Louis. Dr. Kinch said:

“This is a very important insight, one that many health professionals (like myself), have not thoroughly considered. Most passive immune therapies (either sera or monoclonal antibodies) are given for acute events (e.g., snake bite, hepatitis a exposure, etc). The idea is that the likelihood of getting bitten again by the same type of snake is unlikely. In the case of SARS-CoV2, it is feasible (perhaps even likely) that aggressive early use of monoclonal antibody could decrease the magnitude of a natural infection.”

Subsequently, I received an answer from Dr. Eric Topol (MD). He’s the Executive VP and Professor of Molecular Medicine at the Scripps Research. He’s also the Director & Founder of the Scripps Research Translational Institute. Dr. Topol said:

“Yes, that negative feedback is a definite concern. Time will tell on the reinfections tory as to whether that concern is actualized.”

The bottom line: We don’t know. It’s quite possible. To be continued.

Again, the bottom line is that we don’t know if there’s a risk that treating patients with synthetic Covid-fighting antibodies will leave them at risk of re-infection once they wear off. But it definitely seems to be a possibility, based on what I’ve learned. This is just one more reason that, even when a Covid vaccine does arrive, we’ll need to practice good social-health hygiene by masking up, keeping our distance and so forth.

This is no time to be over-confident.