New research shows incidence of cardiac events lower after COVID-19 vaccination
Katrina Borthwick - 5 August 2024
The first batch of Pfizer Covid-19 vaccinations hit New Zealand in February 2021. That means we have now had 3.5 years to study the side effects.
At the time of the rollout there wasn’t any long-term data on the side effects of this particular vaccination. Although research on mRNA vaccines had started in the 1960s, and the first mRNA vaccine was tested on humans in 2013 (for Rabies), it wasn’t really possible to look at the long-term effects of the covid vaccine, because it was so new. So, although the relevant safety tests had been passed, at the end of the day the potential benefits were assessed as outweighing the risk of any side effects.
So out it rolled to billions of people. So far 13.6 billion doses have been administered, with 3.3 billion of those in China alone.
And of course, if you are vaccinating billions of people, some of those people will get rare side effects, including myocarditis, strokes and pericarditis.
According to Medsafe, a rare side effect may affect between 1 in 1,000 and 1 in 10,000 people. That means that if there is a rare side effect, with 13.6 billion doses we are going to see that side effect at least 13.6 million times, but possibly up to ten times that frequency.
In addition to this, people have always been at risk of acute myocarditis and strokes anyway. In fact, according to the New England Journal of Medicine, the lifetime chance of having a stroke is 25%. By my very rough calculations, taking the average global life expectancy of 72.81 years, we can expect to see 1.2% of the global population have a stroke in the 3.5 year window the vaccinations have been in circulation. That’s 163 million people. And this is just strokes - no doubt there will be millions of people with other heart issues, and there would certainly be billions of people who experienced unusual chest pain during this period.
We can add to this that people have a bias for noticing things that do happen, rather than things that do not. Outside of a vaccination drive, or groundbreaking medical research, it would be strange to read a news article about someone who had a vaccination and was totally fine. This is not the sort of news that spreads.
The sheer volume of symptoms that have occurred, either linked to the vaccination in reality or not, has led to fertile ground for conspiracy theories.
What we really needed was the long-term data on whether the vaccinated population are more at risk of cardiac issues than they were prior to vaccination. We can’t really compare to unvaccinated people now, as it’s likely that many of these may have had covid and have cardiac risks associated with that illness, and that confounds the results. However, what we can look at is whether the instances of these events have changed for the vaccinated group following their vaccination.
Recently published (31 July 2024) research, led by the Universities of Cambridge, Bristol and Edinburgh and supported by the British Heart Foundation, gives conclusive results. It uses the long-term data of 45.7 million adults in England between December 2020 and January 2022. Over 90% of the UK population over the age of 12 were vaccinated with at least one dose by January 2022. This is a massive dataset.
They compared the incidence of thrombotic and cardiovascular complications up to 26 weeks after the first, second and booster doses of brands and combinations of COVID-19 vaccines used during the UK vaccination program with the incidence before or without the corresponding vaccination.
The incidences of common events (such as stroke or thrombosis) were lower after vaccination. The incidences of previously identified rare harms (e.g. myocarditis, pericarditis) were higher in the vaccinated population – specifically vaccine-induced thrombotic thrombocytopenia after the first ChAdOx1 (e.g. AstraZeneca) vaccination, and myocarditis and pericarditis after the first, second and transiently after the booster mRNA vaccination (e.g Pfizer). This confirms the earlier studies that pointed out this risk.
It is worth noting that, according to the American Heart Association, people infected with COVID-19 before receiving a vaccine were 11 times more at risk for developing myocarditis within 28 days of testing positive for the virus.
The study effects remained similar for different ages, genders, ethnicities, and medical event histories. The authors state that the findings should be applicable to nations with comparable demographics and healthcare systems.