Health misinformation remains one of Covid’s most damaging legacies, with online falsehoods fuelling vaccine hesitancy, sowing mistrust and eroding public health efforts worldwide.
Shifting policies and political rhetoric in the US have deepened the confusion, with some experts warning that scepticism is partly to blame for the resurgence of vaccine-preventable diseases like whooping cough.
Now, a study involving millions of children in England – covering 85% of the entire youth population – has compared for the first time the cardiac risks of Covid infection with those linked to vaccination.
It found that infection came with a “substantially higher risk” of the inflammatory heart conditions pericarditis and myocarditis compared to immunisation. Where children had been immunised, cardiac risks were also shorter-lived.
Principal author Dr Alexia Sampri, from the University of Cambridge, said: “Our whole-population study during the pandemic showed that although these conditions were rare, children and young people were more likely to experience heart, vascular or inflammatory problems after a Covid-19 infection than after having the vaccine – and the risks after infection lasted much longer.”
Cambridge University teamed up with colleagues from University College London, the University of Edinburgh and the British Heart Foundation to carry out the work.
They were given access to anonymised health records of almost 14 million under 18s. During the study period, from 1 January 2020 to 31 December 2022, 3.9 million children had a first Covid diagnosis and 3.4 million had the PfzerBioNTech vaccine.
There were 2.24 extra cases per 100,000 children with Covid compared to 0.85 extra cases in vaccinated youths
The team discovered there were 2.24 extra cases of pericarditis or myocarditis per 100,000 children with Covid infections, and found that risks lingered for a year. In vaccinated youths, there were only 0.85 extra cases, while risks dissipated after a month.
Co-author Prof Angela Wood, a health and data scientist based at the University of Cambridge, said the team had long wanted to draw this direct comparison, but had been cautious about inflaming an already polarised debate.
“It’s important to understand that the team I lead and work with were really agnostic to what the findings were going to be,” she said. “We’re passionate about using data to provide quantitative evidence, regardless of what we show. We want concrete evidence that can be used by decision makers.”
Wood called for more research to keep pace with new strains of the disease. “Whilst vaccine-related risks are likely to remain rare and short-lived, future risks following infection could change as new variants emerge and immunity shifts,” she said. “That’s why whole population health data monitoring remains essential to guide vaccine and other important public health decisions.”
Main image: Cdc
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