Instagram post misrepresents study linking climate change and diseases

16 January 2023
What was claimed

Research reported in the Daily Mail links migraines, strokes and dementia rates to climate change, but increases are actually explained by harm from Covid-19 vaccines.

Our verdict

The research almost entirely focuses on data from before the Covid vaccines were produced. The vaccines can cause strokes in rare cases, though less often than infection itself. The vaccines are generally safe and are not associated with dementia or long-term migraine disorders.

An Instagram post of a Daily Mail article on research linking climate change to several diseases implies any increased rates are actually due to “the experimental shot”. The page name and other posts reference Covid-19, so we have inferred that they are referring to Covid vaccines in the caption.

The headline reads: “Climate change is making migraines, strokes and DEMENTIA more severe and common, review claims”. The Instagram post shares this with the caption: “Peak stupidity at the end of 2022 for you, and the worst thing about it is people will believe it’s the effects of climate change and not from the experimental shot…”.

The Daily Mail article referenced covers a review of research suggesting rising global temperatures, increasingly severe weather events and pollution may increase the risk of developing these and other diseases, as well as the severity of symptoms. 

The review covers 364 studies published worldwide between 1990 and 2022. 

Only a minority of studies included appear to have been published after the start of the vaccine roll-out which started in the UK in December 2020. Of those studies published in 2021 and 2022, Full Fact could only find one which actually covered data from after the vaccine roll-out began. 

Full Fact has not investigated the quality of this research. But what we can say is that, whatever its merits, it is not claiming there has been a recent post-vaccine rise in the prevalence of these illnesses and conditions. Therefore the Instagram post is misleading to suggest this is what is being claimed in the study or the Daily Mail’s writeup when claiming these effects are actually due to vaccination.

This is a common trope of social media posts, which present screenshots of headlines reporting scientific studies on health risks to falsely claim the media is covering up the fact that Covid vaccines are responsible for increased health issues..

In some cases the articles presented are fakes, or, as in this case, report on studies covering a period largely before the Covid vaccine roll-out.

Full Fact has reached out to Pfizer, AstraZeneca and Moderna as major manufacturers of these vaccines. Pfizer told Full Fact that authorisations of their Covid vaccine around the world “are based on robust and independent evaluation of the scientific data on quality, safety and efficacy”. They referred us to the European Medicines Agency report which states: “Serious safety problems are extremely rare”.

While certain vaccines do appear to have a very small risk of causing stroke, generally Covid vaccines are safe, and are not associated with dementia. Headaches from Covid vaccines are a common side effect, but the vaccines are not associated with development of migraine disorders.

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A stroke is a life-threatening medical condition that happens when the blood supply to part of the brain is cut off. This can be caused by blood clots blocking the flow of blood to the brain or bleeds in the brain.

The Oxford-AstraZeneca vaccine was initially used as part of the UK’s general vaccine response, but advice was given to offer alternatives to under 40s if available after a very small number of people reported blood clots, which can cause strokes, happening after vaccination. 

Up to 23 November 2022, the Medicine and Healthcare products Regulatory Agency (MHRA) had received Yellow Card reports of 445 cases of blood clots with concurrent low platelet counts following vaccination with the Oxford-AstraZeneca vaccine.

This equated to 15.9 per million first or unknown doses, with the incidence higher among younger people.

Fewer clots were reported after the other vaccines. Yellow Card reports are not necessarily evidence of an adverse event being caused by the vaccine. 

Links have also been made with the Pfizer vaccine with some studies finding a small increase in risk of haemorrhagic stroke– bleeding into the brain– after the jab. But these also showed that Covid infection itself increased this risk substantially more.

A large meta-analysis of over 780 million Covid vaccinations found risk of acute ischaemic (clot-related) stroke occurring at a rate of 4.7 per 100,000 vaccinations. By comparison, the authors reported the age-standardised risk of these strokes globally, per year, at between 95 and 98 incidents per 100,000 people and the prevalence among people hospitalised with Covid-19 itself being 1,500–5,000 per 100,000 people.


We have previously fact-checked claims about the Covid vaccines leading to neurodegenerative diseases like dementia and found these to be false.

Dr Alison Cave, chief safety officer at the MHRA previously told Full Fact: “There is no credible evidence that the Covid-19 vaccines are associated with the development of […] neurodegenerative diseases like Alzheimer’s [dementia]”. 

Dementia charity Alzheimer’s Society states that there is no evidence for vaccines increasing the risk of developing dementia nor for worsening existing cases.


Migraines are a specific type of headache felt as a moderate to severe throbbing pain on one side of the head. Patients may suffer from them occasionally or frequently, and treatment is available for those whose symptoms are severe.

Headaches in general are a recognised acute side effect of Covid vaccines. There are anecdotal reports of people’s migraines worsening after they have had Covid vaccines. Some small studies using questionnaires found that people who normally suffer from migraines and other  headaches were more likely to report headaches after the vaccine. As we have reported before, an adverse effect such as a migraine being reported after a vaccine does not necessarily mean that the vaccine caused the headache.

Full Fact was unable to find any evidence of vaccines increasing risk of migraine type headaches in the longer term beyond the immediate week after having a vaccine.

Covid infection, on the other hand, is recognised to increase the number and severity of headaches for weeks after the infection.


Image courtesy of Mika Baumeister

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