Separating falsehoods from facts: Long Covid and Vaccines

Last Updated on July 23, 2023 by Joseph Gut – thasso

July 20, 2023 – The SARS-CoV-2 virus has changed the lives of millions and millions of individuals worldwide. It has also changed the behaviour of the society as a whole with respect to more aggressive and less tolerant behaviour of groups of people among them themselves. The continuing perverse and to huge extend uninformed discussion on vaccines is an example of this sort.

Anti-COVID-19 vaccines have been a game changer for millions of people worldwide in preventing death or disability caused by SARS-CoV-2. In particular, research suggests that they offer significant protection against what is now called  Long Covid. Long Covid describes a series of conditions characterized by long-term, multi-system, often severe health problems persisting or appearing after the typical recovery period of COVID-19 disease. Although studies into Long Covid are under way, there is not yet a consensus on the definition of the term. However, it seems clear, among other evidence, based on numerous spontaneous reports from affected individuals, that Long Covid affects multiple organ systems, including disorders of the respiratory, cardiovascular, gastrointestinal and nervous systems, mental health, metabolism, musculoskeletal pain, anemia and exercise intolerance / post-exertional malaise. The most commonly reported symptoms of Long Covid are fatigue and memory problems. Many other symptoms have also been reported, including malaise, headaches, shortness of breath, anosmia (loss of smell), parosmia (distorted smell), ageusia (distortion or loss of taste), muscle weakness, low-grade fever, and cognitive dysfunction. Estimates of the prevalence of Long Covid vary based on definition, population studied, time period studied, and methodology, generally ranging between 5% and 50%. Health systems in some countries and jurisdictions have been mobilized to deal with this group of patients by creating specialized clinics and providing advice. 

As of yet, there are no tests or biomarkers to diagnose Long Covid and no dedicated therapies to treat it. Possibly false and unfounded claims made by some antivaccine groups that the vaccines themselves may cause Long Covid persist. These claims serve as barriers to vaccination foe many.

However, studies have consistently found that anti-SARS-CoV-2 vaccines prevent the new onset of Long Covid as well as flare-ups for people who already have the condition. Besides the variable appearance of the (clinical) phenotypes of Long Covid, one has limited knowledge about the genetic predisposition of patients for suffering from Long Covid and developing these phenotypes. While patients with certain genetic predispositions suffer preferentially from infection with SARS-CoV-2 (see some blog contributions from thasso (1, 2, 3)), some studies indicate that genes may be involved in Long Covid development as well (see 4, 5). To help separate the facts from falsehoods, there is a body of evidence from what scientific clinical studies have found about vaccination and Long Covid.

Doctors who work in Long Covid clinics have for years suspected that vaccination may help protect against the development of Long Covid. In fact, over the past year, several large, well-conducted studies have supported this notion. In the RECOVER study, published in May in the journal Nature Communications, researchers examined the electronic health records of more than 5 million people who had been diagnosed with COVID-19 disease and found that vaccination reduced the risk that they would develop Long Covid. Although the researchers didn’t compare the effects of having boosters to being fully vaccinated without them, experts have suggested that having a full round of recommended shots may offer the most protection. Similarly, a review published in February in BMJ Medicine concluded that 10 studies showed a significant reduction in the incidence of Long Covid among vaccinated patients. Even one dose of a vaccine was protective. A meta-analysis of six studies published last December in Antimicrobial Stewardship and Healthcare Epidemiology found that one or more doses of an anti-COVID-19 vaccine were 29% effective in preventing symptoms of Long Covid.

In a meta-analysis published in JAMA Internal Medicine, researchers analyzed more than 40 studies that included 860,000 patients and found that two doses of a anti-COVID-19 vaccine reduced the risk of Long Covid by almost half.

Overall, the anti-COVID-19 vaccines work well to prevent serious illness from the virus after acute infection of individuals  That may be a clue to why the vaccines help to prevent Long Covid symptoms at least in some affected individuals..

It is important to note that  in general, the anti-COVID-19  vaccines are considered very safe, but have also been linked to very rare side effects, such as blood clots and heart inflammation. There have also been anecdotal reports of symptoms that resemble Long Covid itself,  a syndrome that has come to be known as “Post Vac“,  an extremely rare condition that may or may not be tied to vaccination. Some individuals developed symptoms suggestive of Long Covid that seemingly linger for months: brain fog, fatigue, heart palpitations, as soon as they got the anti-COVID-19 vaccine,. Actually, a study called LISTEN is being organized at Yale University in an effort to better understand post-vaccine adverse events (PVAE) and a potential link to Long Covid. Given the apparent multitude of organs that may be affected by SARS-CoV-2 and the multitude of genes and variants thereof that underlie the expression and functions of proteins in these organs, this planned study addresses a formidable task. Of course, one has also to realise that by millions and millions of vaccinated people, and by an incidence of perhaps 1 in 10’000 of vaccinated people suffering from an unwanted PVAE developing into Long Covid, society is confronted with hundertausends of such patients. And yes, that poses an additional health problem in itself, just around COVID-19.

Find the latest Long Covid news and guidance in Medscape’s Long COVID Resource Center, and see here a sequence on the issue:

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