Not enough evidence Covid-19 vaccines trigger multiple sclerosis, despite research paper with tiny sample size

Covid-19 vaccines induce multiple sclerosis, or MS. That’s according to posts doing the rounds on Facebook in South Africa.

The posts claim that the World Health Organization (WHO) has released a paper showing there is a link between the vaccines and MS.

One post includes a screenshot of what seems to be a journal article with the headline: “Covid-19 vaccination can induce multiple sclerosis via cross-reactive CD4+ T cells recognizing SARS-CoV-2 spike protein and myelin peptides.” 

Another post includes a video by known Covid-19 misinformer, John Campbell, making the same claim and using the same article as evidence.

The claim has also made its way to Twitter, with some posts including the same screenshot as the Facebook post.

By 19 June 2023, a total of 13.46 billion vaccine doses had been administered globally in the fight against the coronavirus pandemic. So does the vaccine really induce MS?

What is multiple sclerosis?

Multiple sclerosis is a common disease of the central nervous system, which is made up of the brain and spinal cord. The disease is caused by damage to the myelin.

Myelin is the protective layer that forms around nerves and allows electrical impulses to travel along nerve cells. The layer is found around the brain and spinal cord. 

In patients with MS the immune system attacks cells in the myelin, which then causes damage to this proactive layer and an interruption between the nerve signals from the brain to parts of the body.

MS is a lifelong condition that sometimes causes mild symptoms, such as fatigue, but also sometimes serious disability, says the UK’s National Health Service (NHS).

The main symptoms of MS are fatigue, difficulty walking, blurred vision, numbness or tingling in parts of the body, muscle stiffness or spasms, and problems with balance and coordination.

There is no cure for MS, but medication and other treatment options can ease symptoms and help control the condition.

But what about the study mentioned in the social media posts, linking MS and the Covid-19 vaccine?

Study’s abstract was ‘probably too strong’ says author

The article in the screenshots does appear on the WHO website, under the Covid-19 research database, but the paper was not produced by the organisation.

It was published in the 2022 Multiple Sclerosis Journal, by researchers at the University Hospital of Zürich in Switzerland.

The aim of the paper was to establish whether the onset of MS in two patients was caused by the SARS-CoV-2 protein mRNA vaccine.

The two patients experienced symptoms in close proximity to when both had received the Covid-19 vaccine.

There are limitations with case-controlled studies like this paper, which look at factors associated with diseases or outcomes, as they only look for connections between past events and current states. And as we should often remember in science, correlation does not equal causation. 

Studies with small sample sizes also need to be interpreted carefully. A 2008 paper found that smaller studies, while providing results quicker than larger studies, can also yield less reliable or precise estimates. 

Another 2014 paper says smaller studies could prevent proper estimations and conclusions to be extrapolated from findings. Two is a very small sample.

One of the authors of the paper and a neurology professor at the University of Zurich, Rolan Martin, told AP News in an email that the wording of the abstract was “probably too strong”. He said there are other possible causes for MS.

“This issue is very important, and I hope that the usefulness of the vaccines will not be questioned by our observations as there is no doubt that the risks for triggering MS are higher with the natural infection based on current data,” he added.

No evidence proving that Covid-19 vaccines can cause MS

There have been other studies that have looked at the potential link between the coronavirus vaccines and developing MS, but these studies have noted limitations, such as the need for more data and insufficient sample sizes.

There is no evidence that the Covid-19 vaccines can make MS or its symptoms worse or provoke a relapse, or the onset of new or worsening of old symptoms, says the UK’s Multiple Sclerosis Society.

“We have no reason to believe any Covid-19 vaccine will be dangerous for people with MS, including those on immunosuppressive drugs,” the society said.

But what about the claim that the vaccines cause multiple sclerosis?

Africa Check could find no evidence that the coronavirus vaccines can cause an onset of MS. 

Some very rare severe side effects of the vaccines include anaphylaxis (a severe type of allergic reaction), myocarditis and pericarditis, says the US-based Centers for Disease Control and Prevention.

But the onset of MS is not listed as a potential side effect for the Covid-19 vaccines. In fact, some studies have looked at the potential of an onset of MS after being infected with SARS-CoV-2.

Health authorities have also repeatedly explained that the benefit of getting vaccinated against Covid-19 greatly outweighs the risks of side effects from the vaccine.