Rare Links Between COVID Vaccines and Adverse Events Studied

Two Yale University researchers want to understand why symptoms that emerge rarely after COVID-19 vaccines occur.

Persistent symptoms after vaccination — sometimes called “long vax” — are similar to those reported with long COVID, including small-fiber neuropathy and postural orthostatic tachycardia syndrome (POTS). But studies have largely shown that the risk of post-vaccine events do not exceed background rates, or that the odds of a new diagnosis like POTS are greater after SARS-CoV-2 infection than after vaccination.

Akiko Iwasaki, PhD, and Harlan Krumholz, MD, SM, both of Yale University in New Haven, Connecticut, recently expanded their ongoing LISTEN study of long COVID to include people with adverse events after COVID shots, hoping to match abnormal post-vaccine symptoms with corresponding immune responses.

LISTEN participants self-report symptoms and other data through questionnaires. Some individuals are asked to give blood and saliva samples, either at home or at a local testing center, as part of the study.

“We were developing the LISTEN study to better characterize long COVID using clinical, patient-generated, and patient-reported information and, for a subset, to conduct deep immunophenotyping,” Krumholz told MedPage Today.

“Around that time, we also became aware that there were people who were reporting a chronic syndrome, with many similar symptoms after receiving vaccination,” he said. “These people were not political and not anti-vaccination — they had all been vaccinated — but seemed to have symptoms that were persistent and debilitating.”

Both groups of people felt dismissed by clinicians because conventional testing failed to identify a cause, Krumholz noted. “Those with post-vaccination syndrome also encountered some cruel responses, as their experience was used by others to further political agendas on all sides,” he said.

In Neurology, Avindra Nath, MD, of the National Institute of Neurological Disorders and Stroke in Bethesda, Maryland, pointed out that vaccine side effects, including those that affect the nervous system, are difficult to identify.

“Milder complications may have predominantly subjective symptoms which can be challenging to document,” Nath observed. “For example, our group reported cases of peripheral neuropathies temporally associated with the SARS-CoV-2 vaccines. Many patients had subjective symptoms that were dismissed.”

LISTEN recruits participants from the Hugo Health Kindred COVID-19 community. The study currently has about 2,100 participants with either long COVID or post-vaccination symptoms. LISTEN researchers recently posted their first findings — a study of internal tremors and vibrations in long COVID — on the preprint server medRxiv.

MedPage Today recently interviewed Krumholz to find out how LISTEN might shed light on post-vaccine symptoms. An edited version of that discussion follows.

Why is this important to study?

Krumholz: The value of the vaccines is clear. They saved millions of lives and are a modern medical miracle. However, despite their enormous net benefit, it is possible that some people were harmed.

We have to approach this possibility with an open mind and respect the experience of those who have reported a debilitating set of symptoms after being vaccinated. We need to learn more about what this syndrome is — who gets it, what causes it, how can we prevent it, and how can we mitigate or cure it.

What is absolutely clear is that people are suffering. These are people whose lives have unraveled. These people deserve our sympathy, and our help. And perhaps what we learn from their experience and biology — and from those with long COVID — might have benefits for many other people who have syndromes that are poorly defined either after infection or vaccination.

Are you looking at this in a different way than you’re studying long COVID?

Krumholz: In fact, we are taking a very similar approach. There are different issues in people reporting the post-vaccination syndrome, but there are also similarities.

We hope we are creating a method that can be used for other conditions — a highly efficient, very convenient, and ultimately participant-centric approach to scientific studies. We are using many of the same strategies in our decentralized trial of nirmatrelvir-ritonavir (Paxlovid) for long COVID that is just now launching.

What’s the goal of the study?

Krumholz: The goal is to understand long COVID and post-vaccination syndrome, to help people who are suffering to participate in research and be part of the effort to find solutions. Ideally, we will create a better classification system for what these people are suffering [from], a better understanding of the mechanisms, and a pathway to diagnostic tests and therapeutic strategies.

Something of interest about the participant-centric approach of LISTEN is that we are committed to sharing results of the research, and to the extent possible as approved by the IRB [institutional review board], individual results from our testing. We invite some participants to join studies as authors.

We can help these people to know they are not alone, that we believe them, and that we want to help them. We also want to move the discussion of post-vaccination syndrome away from the politics and into the science.

These are conditions where we have no consensus yet, and no evidence-based diagnostics or therapeutics. We are employing novel methods to accelerate knowledge generation. And, yes, we are including people reporting a post-vaccination syndrome because we believe we might be able to help.