by Jason Gale Feb 20, 2024 Microsoft Start<\/p>\n\n\n\n
(Bloomberg) — Vaccines that protect against severe illness, death and lingering\u00a0long Covid<\/a>\u00a0symptoms from a coronavirus infection were linked to small increases in neurological, blood, and heart-related conditions in the largest global\u00a0vaccine safety<\/a>\u00a0study to date.<\/p>\n\n\n\n The rare events \u2014 identified early in the pandemic \u2014 included a higher risk of heart-related inflammation<\/a> from mRNA<\/a> shots made by Pfizer Inc., BioNTech SE, and Moderna Inc., and an increased risk of a type of blood clot in the brain after immunization with viral-vector vaccines<\/a> such as the one developed by the University of Oxford and made by AstraZeneca Plc. <\/p>\n\n\n\n The viral-vector jabs were also tied to an increased risk of Guillain-Barre syndrome<\/a>, a neurological disorder in which the immune system mistakenly attacks the peripheral nervous system.<\/p>\n\n\n\n More than 13.5 billion doses of Covid vaccines have been administered globally over the past three years, saving<\/a> over 1 million lives in Europe alone. Still, a small proportion of people immunized were injured by the shots, stoking debate about their benefits versus harms.<\/p>\n\n\n\n The new research, by the Global Vaccine Data Network, was published in the journal Vaccine last week, with the data made available via interactive dashboards<\/a> to show methodology and specific findings. <\/p>\n\n\n\n Read More: Covid Test Failures Highlight Evolving Relationship With Virus<\/a><\/p>\n\n\n\n The research looked for 13 medical conditions that the group considered \u201cadverse events of special interest\u201d among 99 million vaccinated individuals in eight countries, aiming to identify higher-than-expected cases after a Covid shot. The use of aggregated data increased the possibility of identifying rare safety signals that might have been missed when looking only at smaller populations.<\/p>\n\n\n\n Myocarditis<\/a>, or inflammation of the heart muscle, was consistently identified following a first, second and third dose of mRNA vaccines, the study found. The highest increase in the observed-to-expected ratio was seen after a second jab with the Moderna shot. A first and fourth dose of the same vaccine was also tied to an increase in pericarditis, or inflammation of the thin sac covering the heart. <\/p>\n\n\n\n Researchers found a statistically significant increase in cases of Guillain-Barre syndrome<\/a> within 42 days of an initial Oxford-developed ChAdOx1 or \u201cVaxzevria\u201d shot that wasn\u2019t observed with mRNA vaccines. Based on the background incidence of the condition, 66 cases were expected \u2014 but 190 events were observed. <\/p>\n\n\n\n ChAdOx1 was linked to a threefold increase in cerebral venous sinus thrombosis, a type of blood clot in the brain, identified in 69 events, compared with an expected 21. The small risk led to the vaccine\u2019s withdrawal or restriction in Denmark<\/a> and multiple other countries. Myocarditis was also linked to a third dose of ChAdOx1 in some, but not all, populations studied.<\/p>\n\n\n\n Possible safety signals for\u00a0transverse myelitis<\/a>\u00a0\u2014 spinal cord inflammation \u2014 after viral-vector vaccines were identified in the study. So was\u00a0acute disseminated encephalomyelitis<\/a>\u00a0\u2014 inflammation and swelling in the brain and spinal cord \u2014 after both viral-vector and mRNA vaccines.\u00a0<\/p>\n\n\n\n Seven cases of acute disseminated encephalomyelitis after vaccination with the Pfizer-BioNTech vaccine were observed, versus an expectation of two. <\/p>\n\n\n\n The adverse events of special interest were selected based on pre-established associations with immunization, what was already known about immune-related conditions and pre-clinical research. The study didn\u2019t monitor for postural orthostatic tachycardia syndrome<\/a>, or POTS, that some research has linked<\/a> with Covid vaccines.<\/p>\n\n\n\n Exercise intolerance, excessive fatigue, numbness and \u201cbrain fog\u201d were among common symptoms identified in more than 240 adults experiencing chronic post-vaccination<\/a> syndrome in a separate study<\/a> conducted by the Yale School of Medicine. The cause of the syndrome isn\u2019t yet known, and it has no diagnostic tests or proven remedies.<\/p>\n\n\n\nSafety Signals<\/h3>\n\n\n\n