What the largest study says about the effects of anti-Covid vaccines
Three years after the first administrations, the largest study on anti-Covid vaccines and the adverse reactions that occurred in some cases was carried out. From myocarditis and pericarditis to thrombosis, up to Guillain-Barré syndrome. All the details
They have saved over 1 million lives in Europe alone, however, a small percentage of people who have received Covid vaccines have experienced adverse events, which has opened the debate on the benefits and harms of immunisation. Here's what the largest study to date, conducted by the Global Vaccine Data Network and published in the journal Vaccine , found.
I STUDY
The Global Covid Vaccine Safety (GCoVS) project, as the study explains, was established in 2021 as part of the multinational Global Vaccine Data Network with the aim of facilitating the safety assessment of vaccines. Of the anti-Covid ones, over 13.5 billion doses have been administered globally in the last three years.
The research focused on 13 medical conditions that the team deemed “adverse events of particular concern” among 99 million vaccinated individuals in eight countries and, through the use of aggregate data, identified conditions that occurred multiple times .
“Both things can be true. [Vaccines] can save millions of lives, and there may be a small number of people who have experienced an adverse event,” said Harlan Krumholz, director of the Center for Research and Outcome Evaluation at Yale New Haven Hospital.
THE ADVERSE EVENTS INVESTIGATED
From the first months following the first administrations of anti-Covid vaccines, the most common adverse events encountered concerned neurological, blood and cardiac conditions. In particular, the risk of myocarditis and pericarditis following the Pfizer and Moderna mRNA vaccines and that of blood clots, responsible for possible thrombosis, with the Johnson & Johnson and AstraZeneca vaccines. Viral vaccines, like the latter two, have also been linked to an increased risk of Guillain-Barré syndrome, a neurological disease in which the immune system mistakenly attacks the peripheral nervous system.
THE RESULTS
“The analysis – we read – confirmed the pre-established safety signals for myocarditis, pericarditis, Guillain-Barré syndrome and cerebral thrombosis of the venous sinuses”. Additionally, “other potential safety signals have been identified that require further investigation.”
As per previous hypotheses, in fact, the study found that myocarditis was identified consistently after the first, second and third doses of mRNA vaccines and the highest increase in the observed/expected ratio was observed after a second injection of Moderna. The first and fourth doses of the same vaccine were also associated with an increase in cases of pericarditis.
As regards the cases of Guillain-Barré syndrome, which occurred in 190 cases while 76 were expected, the researchers observed a link with the AstraZeneca vaccine, which was not noted with the mRNA ones. The vaccine developed by Oxford University was also linked to a three-fold increase in cerebral venous sinus thrombosis, identified in 69 events, compared to the expected 21. The risk at the time led to the withdrawal or restriction of the vaccine in Denmark and many other countries. Myocarditis has also been linked to a third dose of AstraZeneca in some, but not all, study populations.
OTHER PATHOLOGIES AND THE INCOMPREHENSIBLE LONG COVID
The study then identified other signals of possible adverse events that require further investigation. For example about transverse myelitis, an inflammation of the spinal cord, after viral vector vaccines and acute disseminated encephalomyelitis, inflammation and swelling of the brain and spinal cord, following both viral vector and mRNA vaccines.
However, chronic post-vaccination syndrome still remains a mystery which, like long Covid, is characterized by a wide variety of symptoms and clinical pictures, including chronic fatigue syndrome, migraines, muscle pain or cardiovascular diseases. These symptoms and so-called “ brain fog” were among the common symptoms identified in more than 240 adults with chronic post-vaccination syndrome in a separate study conducted by the Yale School of Medicine.
This is a machine translation from Italian language of a post published on Start Magazine at the URL https://www.startmag.it/sanita/cosa-dice-il-piu-grande-studio-sugli-effetti-dei-vaccini-anti-covid/ on Mon, 19 Feb 2024 15:16:29 +0000.