Gaffney is an assistant professor at Harvard Medical School and a pulmonary and critical care physician at the Cambridge Health Alliance.
Recently, the notorious conspiracy theory peddler Alex Jones shared an "Infowars" video on X lambasting the "horrific side effects" of Covid vaccines: "Yale scientists link COVID vaccines to alarming new syndrome causing distinct biological changes to the body," his post read. News of the new study spread like wildfire throughout right-wing anti-vaccine circles, amplified by the likes of Alex Berenson, Elon Musk, and Joe Rogan, who touted the study as yet more proof the public had been lied to about all things Covid.
Surely bolstering their case was the fact that this particular study -- an analysis linking Covid vaccination to a so-called "post-vaccination syndrome" (PVS) with immunological changes -- was led by prestigious Yale scientists and covered by the New York Times. The ecstatic response to the research among anti-vaccine activists was also driven by the fact that it seemingly vindicated a very specific theory that has been rampant in those circles for years: that Covid vaccines were driving chronic disease through production of dangerous "spike" protein that infiltrated the body.
But a closer look at the basic approach and assumptions undergirding this research, the inclusion of vaccine critics among the co-authors, and the "patient-led" paradigm from which it emerged all shed serious doubt on the study's conclusions. In this age of surging anti-vaccine and anti-science sentiment, harm will likely follow.
To be clear, vaccines are medicines, and all medicines have side effects -- even when the net benefit is large. Diligently studying such side effects is a good thing. And when good science is cynically weaponized for political purposes, that's hardly researchers' fault: None of us can control how our work gets used (or misused) once in the public domain.
But there's much more to this story. The study is premised on a condition the researchers call "post-vaccination syndrome," or PVS, which, they posit, bears close resemblance to long Covid. They define PVS based entirely on patient reports of nonspecific symptoms like fatigue, brain fog, difficulty concentrating, and muscle aches that they believe were caused by Covid vaccines. Make no mistake: Patients are authorities on their symptoms, on what they feel, and how they suffer. These testimonials should never be doubted or minimized by physicians like me. But all of us struggle to know the etiology -- the causative agent -- of our symptoms.
After all, symptoms common among PVS patients are also common in the general population, most of whom were also vaccinated for Covid-19. So too is it common to misattribute symptoms to any number of microbes, agents, or other exposures. Throughout history, endless dubious diagnoses have emerged and faded to explain nonspecific symptom complexes: chronic Lyme disease, chronic candidiasis, and Morgellons to name a few. We can and should question whether these symptoms are indeed caused by vaccines, and it isn't "medical gaslighting" to say they may not be -- it's good medicine, albeit requiring care, nuance, and humility in the clinic.
Moreover, there are perfectly plausible alternative explanations for the symptoms these patients experience. Notably, in the Yale study, people alleged to have PVS also had higher depression and anxiety scores -- each of which is linked to multifold physical symptoms. Additionally, uncertainty and distress surrounding the vaccination experience, but not the vaccine components themselves, could drive some symptoms: In randomized clinical trials of Covid vaccines, for instance, 15.9% recipients reported fatigue and 18.4% headache as adverse events -- among those in the placebo arms.
Such "nocebo" effects (i.e., unpleasant, very real physical symptoms in part driven by our brain's expectations) are common and familiar to physicians. Related, but more severe, are the "functional neurological disorders" that have been described in medical journals after Covid vaccinations, some instances of which went "viral" in videos shared on social media by anti-vaccination accounts. These syndromes (which can include symptoms like weakness of an arm or leg, or bodily shaking) are not due to any structural damage to the brain or body, but glitches in brain pathways that can be instigated by psychosocial cues and other factors, and can improve with time or rehabilitation.
Yet, the Yale study did not explore common alternate hypotheses that could explain what they saw in their cohort. Instead, after defining a group of PVS patients solely based on belief in a vaccine-symptom linkage, the researchers performed hundreds of biological assays on these patients and a group of controls, and found some statistically significant differences. This seems to demonstrate that those with the syndrome "show distinct biological changes," as the Times reported (or, as Alex Berenson baselessly suggested, that PVS is akin to AIDS).
But there's no evidence these differences mean much in the real world: They are differences (on average) in basic science parameters between groups, not outright abnormalities in the sorts of clinical tests that you and I have when we go to a doctor where "abnormal" may plainly equate to disease. Differences were seen in only some of the huge number of tests performed, were often small (with much overlap between cases and controls), and though statistically significant may have little or no real-world implications for health or illness. Moreover, generally speaking, differences in immune parameters can be associated with diverse processes, including major depression. Similarly, the study's finding that higher levels of antibodies to the Epstein-Barr virus implicate reactivation of this common virus as a driver of PVS symptoms is unwarranted -- an elevation in such antibodies is nonspecific and associated with different things, again including depression.
Yet the findings that most enthused antivaccine activists were those that pointed to spike protein as a possible driver of PVS. Spike proteins are found on the outside of the Covid virus but are also contained or made by vaccines to get our immune systems to produce antibodies that protect us against Covid. For whatever reason, since Covid vaccines became available, anti-vaccine activists have fixated on the idea that spike protein produced by the vaccines are gravely hazardous. For instance, since 2021, pseudoscientific treatment protocols from the anti-vaccine group Front Line COVID-19 Critical Care (FLCCC) Alliance -- led by ivermectin evangelist Pierre Kory who had his board certification stripped for disseminating Covid misinformation -- asserted that these protocols could treat both long Covid and what they described as a post-vaccination syndrome driven by "spike protein from the vaccine." This fixation has led to rampant fear-mongering that the blood supply is tainted with spike protein from vaccine recipients, even leading one anti-vaccine activist who needed a blood transfusion to rush to Mexico in 2021 for "unvaccinated blood." That same year, a private school in Miami prohibited recently vaccinated school teachers from having contact with students out of fear that they would "shed" spike protein and harm the students. Yet what these extremely sensitive spike assays are actually telling us remains fuzzy. Inconsistent results across previously published studies employing spike assays suggest much more research is needed to establish the basic reproducibility and implications of the results.
The significant overlap between this study and the claims made by indefensible cranks raises still more concerns upon a closer look at some members of the research team: Two of the co-authors, described as "independent researchers," are part of the organization React19, a vaccine injury advocacy organization engaged in Covid vaccine injury litigation. One of these individuals is personally a vocal and high-profile litigant who supported Robert F. Kennedy Jr.'s nomination as Health and Human Services secretary and who published a vaccine-injury testimonial blurbed by Kennedy. A third co-author has made dubious claims about chronic Lyme disease, and has endorsed supplement use without evidence as a treatment for long Covid. A fourth has speculated online that another potential co-infection culprit in PVS might be "dormant Bartonella infection," a real but rare pathogen that for unclear reasons has emerged in fringe medical circles as a commonly invoked tick-borne "Lyme coinfection," as described by Centers for Disease Control and Prevention. These are red flags, to say the least.
To be fair, the study team does include very well-respected scientists, the authors describe their findings as "early stage," and the co-investigators do seem genuinely motivated by the idea that this publication would give a voice to a community of patients who are experiencing real suffering. This ethos is codified in the very name of the larger study from which this one emerged, the "Listen to Immune, Symptom, and Treatment Experiences Now," or LISTEN Study. Listening to patients is, of course, essential to good medicine.
But diagnoses are pragmatic constructs, structured both by biomedical realities and by social and political discourses. They can help us identify useful treatments and avoid injurious exposures, but also lead us to unhelpful remedies or to misunderstandings of our illness. Particularly during this age of unprecedented and politicized anti-vaccination fervor, the establishment of a dubious "post-vaccination syndrome," on shaky science, is dangerous.