Jan 19 2021

Be Skeptical of Video Showing Vaccine “Side Effect

This was inevitable. We are in the midst of a massive rollout of two new vaccines for COVID-19. Anxiety and fatigue levels from the pandemic are already running high, and there is a pre-existing anti-vaccine movement who is sure to exploit this. But perhaps most significantly, we are now living in a post-social media world. Information, even medical or scientific information, may get to the public unfiltered, ripe to be misinterpreted by people who do not understand the relevant science. Such is the case with a “viral” video showing a woman who claims her symptoms are a side effect of the Moderna vaccine (short answer – they almost certainly are not).

Messaging is critical to the success of public health measures. Normally information about possible side effects from a drug or vaccine would be filtered through medical experts. When millions of people are involved there is going to be a lot of noise. Coincidence alone would result in many negative outcomes occurring by chance alone shortly after getting a vaccine. Epidemiologists need to look for patterns in the data that indicate there is likely to be an actual causal relationship to the vaccine. It helps if there is also a plausible mechanism. This system has captured vaccine side effects in the past, so you cannot reasonably argue that the system is rigged not to find such associations. The swine flu vaccine in the 1970s caused cases of Guillaine Barre Syndrome. A specific flu vaccine (Pandemrix – no longer on the market) likely caused cases of narcolepsy in 2009. So if any of the current COVID vaccines have a similar side effect, we will catch it.

Reporting scary anecdotes that have not been scientifically evaluated to the public is not a good idea. This is likely to misinform rather than inform, and will have a death toll attached to it. But with social media there is no way to stop this from happening, so we just have to do damage control when it does.

As a side note, I have to point out that I usually refrain from commenting on a specific individual’s medical condition in public. This is to respect the privacy of those individuals, and also because if I have not personally examined them and taken their history, commenting is inappropriate. But medical science communicators can comment about topics relevant to a public case or issue. I can speak generally about the relevant topics. There is also an exception when a private person puts their own medical history into the public domain, especially if they also use that history to make recommendations to the public, and doubly so if those recommendations are false and harmful. They have surrendered any expectation of privacy and they have made their own personal history relevant to the discussion about a public health issue. That is the case here.

The story is of a woman who has been experiencing involuntary shaking shortly following her first dose of the Moderna vaccine. Quirky neurological side effects can occur from vaccines, as the two examples I cited above indicate. In both cases, however, the symptoms corresponded to a known neurological phenomenon. This is where filtering such information through someone with appropriate medical expertise is important. In neurology we separate our analysis of a patient’s signs and symptoms into phenomenology and etiology. This can be a tricky concept to understand but it’s critical to making sense of what’s happening.

Etiology is the easier concept – it is the ultimate pathophysiological cause of the condition. Etiology is a specific disease or syndrome, or a specific mechanism of injury. Phenomenology does not relate directly to the cause, but rather deals with what is not working in the body to produce the signs and symptoms. Because the brain is the most complex organ in the body, neurological phenomenology is also the most complex. But let me give you an example to illustrate the difference. If a patient presents with difficulty walking, that is their complaint. “Difficulty walking” is neither the neurological phenomenon nor the etiology, it’s just what the patient experiences. Let’s say after examination it’s clear that the patient has weakness in their legs, and this weakness is entirely responsible for their difficulty walking. Weakness (perhaps in specific identifiable muscle groups or a specific pattern) is the phenomenology. We then need to determine the etiology of the weakness, which could be anything from a stroke to nerve damage.

If we apply this approach to the woman with the shaking, we need to first determine the phenomenology. This is a classic presentation in neurology, specifically in the subspecialty known as movement disorders – what phenomenon is the involuntary movement? This is also one of the cases in which a video provides much of the needed information to make a determination. This is not as complete as an exam, but it can be very good. At this point we know most of the circuits in the brain, and have specifically worked out all the pathways involved in movement. We also know what it looks like when there is a lesion or problem with each of these pathways. There are only so many ways the body can pathologically move because of a glitch. That is the phenomenology. When looking at the video it is possible to say what the movements are not – they are not convulsions, dystonia, myoclonus, ballismus, chorea, ticks, or any specific kind of tremor. After eliminating all the known phenomena of involuntary movements, what’s left?

This is a situation we always approach carefully in neurology. We don’t want to make the argument from ignorance, but eliminating everything possible is significant. There are essentially two possibilities left – either this is a new phenomenon currently unknown to neurology, or it represents a conversion disorder, which is essentially psychological. But are there any positive signs that indicate a conversion disorder, rather than this only being a diagnosis of exclusions? Sort of. Experienced clinicians who have seen many patients with psychological movements develop an eye for what they tend to look like. There may be specific features, but also a gestalt. In any case – if I looked at this video without any context, I would conclude this is overwhelmingly likely to be conversion disorder. Apparently every physician who has seen this patient agrees, and other neurologists have commented publicly that this is likely the case.

Comments on social media tend to fall into two categories – that this is clearly a vaccine side effect or that the patient is faking. Neither is likely to be true. Conversion disorder is not “faking” (faking is technically called a factitious disorder, or more colloquially, malingering). People experiencing a conversion disorder do not have insight into what is happening. This also is a real medical disorder, just a psychological one, and should not be stigmatized. But we do need to understand it in order to properly deal with it.

If the movements are a manifestation of a conversion disorder (which is very likely) then there is no plausible etiological connection to the vaccine, other than as a psychological trigger. Also, it is important to note that there is an elaborate reporting infrastructure to capture and analyze all potential side effects to the COVID vaccines. If new side effect do crop up, we will see them. So far there are only minor side effects, even after millions of doses. This does not mean the risk is zero, but it does mean that the risk of any serious side effect is millions to one against. This further means that the probability of being protected by the vaccine is orders of magnitude greater than of being harmed by it. Don’t be scared by one-off stories of dubious significance. The math here is absolutely clear. Get the vaccine.


No responses yet