Adults are at greater risk of developing heart infection after contracting Covid than from a vaccine, research suggests.
A real-world study of more than 2 million Israelis found that the risks of developing myocarditis after a Covid shot were greater than the risks of the virus itself.
Researchers said the condition occurred in fewer than three per 100,000 patients who received the vaccine and would not have developed it otherwise.
That rate was much higher — 11 per 100,000 — among people infected with the virus, they said.
People who contracted the coronavirus were at a much higher risk of developing irregular heartbeats, kidney damage and blocked lung vessels compared to vaccinated participants.
The study warned that the risk of heart inflammation was slightly increased by vaccination, but the complications are still incredibly rare.
The findings only apply to adults. On the other hand, it has been shown that children have a negligible risk of getting sick with Covid in any way.
This is why the UK Vaccine Advisory Group has spoken out against the routine jabbing of young people under the age of 16. They say the small risk of side effects is still greater than the risk of Covid.
Researchers in Israel saw 2.7 extra cases of myocarditis per 100,000 people injected with the Pfizer vaccine, but this shot up to 11 extra cases for every 100,000 people contracted the virus
The graph shows the number of extra cases of each side effect per 100,000 people after a Pfizer injection (gray bars) and a Covid infection (orange bars)
The Covid vaccines have undergone extensive safety testing before being rolled out to the public, but because trials involve small groups, they often cannot detect extremely rare side effects.
Tests haven’t picked up any cases of myocarditis, but cases of the side effect were recorded in Israel, the US and the UK after countries began vaccinating their populations in the millions.
Most cases of myocarditis following Covid vaccines have been identified in young men, which appears to be supported by the study.
Researchers from the Clalit Research Institute in Ramat Gan in Israel examined health records of 2.1 million people over the age of 16 in Israel to collect data on the real cases of side effects after a vaccine or Covid infection.
The country exclusively used the Pfizer shot in its industry-leading vaccination campaign and was the first to reach 50 percent use.
The experts compared about 880,000 people who had received a double shot on May 24 with the same number of unvaccinated people of a similar age and health background.
WHAT IS MYOCARDITIS?
Myocarditis is an inflammation of the heart muscle. There are no specific causes of the condition, but it is usually caused by a virus.
Some of the most common infections that cause myocarditis are those called adenovirus and Coxsackie B.
It can be caused by the common cold, hepatitis B and C, and herpes simplex virus.
The most common symptoms of the condition are chest pain, fever, rapid heart rate, fatigue, and shortness of breath.
If the inflammation damages the heart muscle or the fibers that conduct electrical pulses to the heart, complications can arise.
They can develop quickly and include sudden loss of consciousness, an abnormally fast, slow or irregular heartbeat.
In very severe cases, the condition is fatal, causing heart failure or sudden death. The inflammation enlarges the heart and creates scar tissue, forcing it to work harder and making it weaker.
In most cases of viral myocarditis, the disease resolves and there are no complications.
But in rare cases, when the inflammation is severe, there may be damage to the heart that needs to be monitored and possibly a heart transplant.
Myocarditis can return, but there is no known way to prevent it. The risk of recurrence is low, about 10 to 15 percent, according to the Myocarditis Foundation.
It is difficult to measure the prevalence of myocarditis because there is no widely available test for it.
In 2010, approximately 400,000 people worldwide died from heart muscle disease – cardiomyopathy which also includes myocarditis.
The expert consensus estimates that up to 40 percent of dilated cardiomyopathy results from myocarditis, according to the National Organization for Rare Disorders.
Their study, published yesterday in the New England Journal of Medicine, calculated how many cases of 25 different side effects there were in each group.
They compared these findings with incidences of the side effects among 170,000 people who tested positive for Covid and a similar-sized control group who did not have the virus.
They saw about three additional cases of myocarditis per 100,000 people 42 days after they received a second dose of Pfizer.
But among those who tested positive for Covid, the risk was up to 11 additional cases for every 100,000 people.
Myocarditis is usually caused by a virus and can be fatal in very severe cases, but most associated with Covid shots have been mild.
On July 28, the UK registered 256 cases of the condition after giving out 46.7 million shots.
It’s unclear how many cases of the condition are common in the general population, as most cases are mild and not well-researched, according to Public Health England.
But among the control group in the study, there were six cases of myocarditis, compared with 21 in those who received a Pfizer shot.
The average age of those who developed the condition after a Pfizer injection was 25, while 91 percent were male.
The researchers concluded that the Pfizer shot was not associated with an increased risk of most of the side effects they studied.
There was a chance of developing myocarditis after a Pfizer shot, but this risk was much higher after a Covid infection, they said.
Meanwhile, there were 11 additional cases of pericarditis per 100,000 people after Covid infection, while there was only one additional case per 100,000 people after the Pfizer shot.
dr. Ben Reis, study co-author and chief of predictive medicine at Boston Children’s Hospital, told the… New York Times: ‘Coronavirus is very dangerous, and in many ways very dangerous for the human body.
“If the reason anyone has been hesitant to get the vaccine until now is fear of this very rare and usually not very serious side effect called myocarditis, well, this study shows that that same side effect is actually associated with a higher risk if you are not vaccinated and you become infected.’
The study also calculated that there were 166 extra cases per 100,000 people of arrhythmia – an irregular heartbeat.
Viral diseases are a common cause of the condition, which can lead to strokes and cardiac arrest.
Meanwhile, researchers saw six fewer cases of this condition than they expected in people who received the Pfizer shot.
People who contracted the virus were also 125 times more likely to have kidney damage.
Researchers also identified 62 more cases of a pulmonary embolism per 100,000 than expected after contracting Covid, which is a blocked blood vessel in the lung.
And there were 43 more cases of blood clots in the vein — called deep vein thrombosis — per 100,000 after a positive test.
Side effects associated with the Pfizer shot include 78 more than expected cases of swollen lymph nodes per 100,000 people, which is a common side effect of vaccines.
It comes at a time when the Joint Vaccination and Immunization Committee (JCVI), which advises the government on vaccine rollout, is deciding whether to roll out the shots to younger groups.
Earlier this month, people over 16 were invited to get a shot, but the scientists have yet to decide whether younger groups should get the vaccine.
But NHS England have been told to prepare to roll out jabs for all over 12s in the coming weeks.
Professor Lawrence Young, a virologist at the University of Warwick, told MailOnline: ‘It is important to recognize that Covid is a very nasty disease that affects not only your breathing but also your body’s blood clotting system.
‘This can affect other organs, such as your heart and kidneys, which can lead to long-term damage.
‘The risk of Covid infection is much greater than the rare myocarditis associated with the Pfizer vaccine.
“Most reported cases of post-infection myocarditis are mild and individuals respond well to standard therapy.”
Professor Robert Storey, an expert in infection, immunity and cardiovascular disease at the University of Sheffield, told MailOnline: ‘Many decisions we make in life affect our health risks and benefits.
“The best chance for a healthy life comes from making decisions that increase our chances of staying healthy.
‘Covid vaccines are a good example of this.
“There appear to be very small risks associated with these vaccines with less than about 1 in 30,000 risk of heart inflammation with the Pfizer vaccine or 1 in 100,000 risk of blood clots with the AstraZeneca vaccine.”
‘These risks of cardiovascular complications are small compared to the much higher risks of Covid infection and the rapid spread of the delta variant is clearly a huge danger for people who have not been vaccinated.
Covid infection carries a much higher risk and a much greater number of unpleasant complications, including a much higher risk of heart inflammation or blood clots.
‘Interestingly, the recent study showed a lower risk of brain haemorrhage in, among others, people who received the vaccine. So it really emphasizes the importance of vaccination to increase your chances of staying healthy.’