In recent, widely shared blog posts, virologist and veterinarian Geert Vanden Bossche makes some striking claims: vaccinated people would carry the virus for longer, they would develop autoimmune diseases and within a few months there would be a wave of serious Covid19 cases among vaccinated people. Sounds worrying, but is it true?
Vaccines do not extend the period during which people produce infectious viruses
Vanden Bossche states that vaccinated people carry and excrete the virus for longer and cause more variants to arise, even if they have no symptoms. That is not true. If we put together the findings of a lot of research from the omicron period, we see that the period in which people test positive on a PCR test does not differ noticeably depending on whether you have been vaccinated or not. Most studies indicate that you test positive up to ten days after the onset of symptoms. But a PCR test is not the best way to determine whether someone is still producing and excreting functional virus particles. It detects the genetic material of the virus, but many proteins are still needed that must be assembled correctly to make real virus particles.
During the omicron period, some studies examined whether vaccinated people produced functional virus particles for a shorter period of time, but this turned out not to be the case. On average, people produced such virus particles up to three days after the first symptoms. This was the case when the delta variant was circulating: in those who had been fully vaccinated, if they were infected, hardly any functional virus particles could be found. For those who had not been vaccinated, this was successful: on average up to four or five days after the first symptoms.
Vaccines do not lead to the faster emergence of variants
A virus can only mutate and lead to new variants if it manages to copy and further spread its genetic material. The available data show that the vaccines limit this (especially with previous variants) and therefore do not promote the emergence of new variants.
There is too little information at the time of writing to make statements about how long infections with the current variants lead to the excretion of live virus particles. A small study shows that slightly more genetic material from the virus ends up in the stool of those infected with the latest variants called JN.1 and BA.2.86, but no distinction is made between vaccinated and unvaccinated people. There appear to be no studies yet that map out how long people excrete functional virus particles with these variants.
Experts contradict Vanden Bossche’s claims
Factcheck.Flanders consulted experts from the Center for Vaccinology (CEVAC), affiliated with Ghent University Hospital. Head of CEVAC, professor of vaccinology Isabel Leroux-Roels, previously investigated claims by Vanden Bossche that were not scientifically substantiated. According to her, the statements assessed in this article are also hardly supported by existing scientific evidence.
Bart Jacobs, doctor and researcher at CEVAC, adds that the vaccine reduces the speed at which variants arise: “the vaccines ensure that the number of infected people decreases and the chance of variants developing is limited. Furthermore, the vaccines mainly target the spike protein of SARS-CoV-2. This protein remains relatively stable between different variants, maintaining broad protection. There are many studies showing that even revaccination against the original corona vaccine still provides protection against serious infection or hospitalization.”
Vaccines determine which mutations make the virus more successful, but regular infections do the same
A large American study compared the mutations that the coronavirus had in vaccinated and unvaccinated people during the omicron period. The researchers concluded from this that certain mutations were more common among vaccinated people than unvaccinated people. That makes sense, because viruses are constantly mutating. If that mutation helps to evade pre-existing immunity somewhat, that virus can infect people with pre-existing immunity somewhat more easily. But those mutations were also found in those who had not been vaccinated.
In addition to the specific mutations, they also examined how well the virus binds to the ACE-2 receptor (the protein through which the Covid19 virus can enter our cells) and how well the virus evades the immune system. This showed that there was actually no difference between those who had immunity through vaccination or through previous infections. This is at odds with what Vanden Bossche says: he states that the virus will mutate in vaccinated people in such a way that it would become much more pathogenic. The same claim has previously been debunked and recent data on the variants circulating in early 2024 show that they are no more seriously pathogenic than the earlier variants.
Dr. Jacobs confirms that infections without previous vaccination also lead to variants: “Natural infection also drives the emergence of variants: unvaccinated people who become infected contribute to the evolution of the virus. Selection pressure exists anyway: viruses are constantly mutating. The longer such a virus circulates in people, the more it adapts to humans, which usually means that it becomes less pathogenic in people with a well-functioning immune system.”
No evidence of an increase in autoimmune diseases due to the vaccines
According to Vanden Bossche, there would be an increase in autoimmune diseases in the future. There are no real indications for this: Vanden Bossche states that the immune system of vaccinated people would react too strongly against a piece of protein in the coronavirus. The immune response against the so-called “universal peptide” would lead to autoimmune diseases. That is not true. There is indeed a peptide that occurs in all known coronaviruses, says the 2009 study to which Vanden Bossche refers, but that piece of protein does not occur in humans at all. So it cannot lead to an autoimmune disease.
Moreover, it is unclear why this would only happen to vaccinated people, because non-vaccinated people also come into contact with that piece of protein. A 2021 study found that those who had experienced Covid19 sometimes had an effective immune response against this piece of protein. Many other studies found similar results. If this was actually problematic and would lead to autoimmune diseases, we would have noticed this already.
Previous predictions by Vanden Bossche did not come true
It is not the first time that Vanden Bossche has launched similar warnings. In 2021, an open letter from him went viral worldwide, which was then refuted by several fact-checkers.
In a blog post from May 2022, Vanden Bossche predicted that a new and more seriously pathogenic variant of the coronavirus would emerge “soon”. He also talks about “six months after writing”. We now know that that prediction also did not come true – the variants that emerged after that blog post are no more seriously pathogenic than the earlier variants.
Conclusion
Worrying warnings about Covid19 from Vanden Bossche went viral on social media, but lack substantiation. The corona vaccines do not extend the period in which virus particles are excreted. There are no indications that the corona vaccines would lead to a wave of autoimmune diseases in the future. Previous striking predictions by Vanden Bossche also did not come true.
Tags: vaccinated people longer carry coronaviruses
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