A new Israeli investigation offers some surprising but reassuring news about the safety of covid-19 vaccines. The study found that the Pfizer / BioNTech mRNA vaccine was not associated with an increased risk of most potential adverse events. And for suspected rare complications such as myocarditis, the risk was still substantially higher in those who had covid-19.
When symptoms appear after taking a medication or vaccine, they are known as adverse events. These events may be true side effects of a treatment, but they may have occurred independently of the medication. A key way to determine the risk of a potential side effect is to see how often a population of people who receive treatment experience these symptoms compared to those who did not take treatment, the latter being a control group in the world. real. And this is what these researchers did, who analyzed data from Israel’s largest healthcare system since the start of the vaccination campaign late last year. The study collectively involved more than a million people.
The researchers compared the documented adverse event rate in vaccinated people with matching unvaccinated people in age and other demographic data. Ultimately, they found that the vaccine was not associated with a higher risk of adverse events in the 42 days following vaccination. There were some events with a stronger link to vaccination. These include appendicitis, swollen lymph nodes, and myocarditis (heart inflammation). But when the researchers examined people with confirmed covid-19 and compared them to vaccinated people, the difference was clear.
Potentially serious adverse events were much more common in those infected than in those vaccinated. For example, the rate of vaccinated myocarditis was 2.7 documented cases per 100,000 people, but it was 11 cases per 100,000 of those infected, a difference of four times. There were also other conditions that vaccinated people had no additional risk of suffering from, but were more likely to appear in people who contracted covid-19, such as heart attacks, kidney damage, and lung embolisms.
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“[O]Your results indicate that SARS-CoV-2 infection is a very strong risk factor for myocarditis and also substantially increases the risk of multiple serious adverse events, ”the authors wrote in their study. published Wednesday in the New England Journal of Medicine.
While it may seem obvious that getting a vaccine to get immunity to a disease will be safer than getting the disease itself, especially a disease that is ending. 4.5 million people in less than two years: it is always important to monitor for significant side effects that may have gone unnoticed in clinical trials.
Since its authorization last year, scientists have found that vaccinated people may have a higher risk of some adverse events not documented in the original clinical trials, including myocarditis in those receiving a vaccine against mRNA such as the Pfizer or Moderna trait. And there have been cases of serious diseases and even vaccine-related deaths, such as death of BBC journalist Lisa Shaw in May after a rare blood clotting condition linked to the AstraZeneca vaccine. But so far, all real-world data has shown that such serious events remain very rare, while deaths from covid-19 and long-term complications are much more common. In the US alone, there may be vaccines prevented up to 140,000 dead in early May. In other words, the benefits of covid-19 vaccination continue to far outweigh the risks.