The WHO Global Advisory Committee on Vaccine Safety releases regular statements as any new vaccine safety signals are investigated and confirmed. Other signals have not been substantiated by evidence at all. However, as the authors of the study pointed out, further studies are needed. A recent study, for example, suggests a common syndrome call postural orthostatic tachycardia syndrome (POTS) occurred after vaccination but was five times more common after COVID-19 itself. There are many “signals” or suggestions that other conditions are linked to COVID-19 vaccines.
However, the risk for these events is lower than the serious risks from COVID-19 itself in the absence of vaccination. Other rare conditions related to COVID-19 vaccines include anaphylaxis, Guillain-Barré syndrome and immune thrombocytopenia. While most people with myocarditis related to vaccine have mild symptoms and recover over days or weeks, a small number have more serious disease or prolonged symptoms.
Myocarditis (inflammation of the heart muscle) has been seen more frequently, particularly in teenage boys and young men after mRNA vaccines (around two to ten cases for every 100,000 second Pfizer COVID-19 vaccine doses). This was rapidly reported and its detection shaped the COVID-19 vaccine rollout. It occurs in around one in 50,000 doses of the AstraZeneca COVID-19 vaccine, with 173 cases reported in Australia. Thrombosis with thrombocytopenia syndrome is a serious but rare clotting disorder. Some rare but serious events caused by COVID-19 vaccines were detected within months of the vaccine rollout. These studies look at whether the risk of a condition is increased in people shortly after vaccination, compared to other times or in unvaccinated people. Detailed epidemiological studies have also included many millions of people. Safety monitoring has occurred across the whole populations in more than 190 countries. As vaccines are given to the wider population, many countries (including Australia) monitor for rare and serious side effects. More than 13 billion COVID-19 vaccine doses have been given globally. These trials are large – around 20,000-30,000 people are closely monitored for many months – but can only detect relatively common side effects. Clinical trials, including for COVID-19 vaccines, compare a group who receive the vaccine with another receiving a placebo (or another vaccine).
Covid vaccine side effect trial#
Safety assessments start early in product development then proceed to clinical trial assessments. Strong vaccine safety systems are designed to identify and investigate potential new health issues related to a vaccine. The key question is whether a vaccine caused or worsened the risk of a condition. Heart attacks, strokes, new autoimmune diseases, and death can all occur shortly after a vaccine. It’s important to consider these other factors, because not everything that happens after a vaccine is due to the vaccine. But other factors are crucial when determining whether one thing caused another. The condition occurring in a window of time after vaccination is an obvious criterion. Good vaccine safety systems address these questions. People naturally want to know the cause of a problem.
This is particularly the case when the problem has an uncertain cause, is not well understood or is only recently described. In any new large vaccine rollout, some people will experience a serious medical problem in the period after the new vaccine is given, and wonder “was it from the vaccine?”. We’re vaccine experts and while we can’t specifically comment on Phelps’ concerns, here’s how adverse events are tracked, confirmed and prevented. This has prompted public discussion about severe side effects, known as “adverse events”, after COVID-19 vaccines. Phelps herself experienced breathlessness and blood-pressure fluctuations after her second dose. In her submission to the parliamentary inquiry into long COVID, Phelps said her wife Jackie Stricker-Phelps had ongoing neurological problems after her first vaccine. This article by Professor Chris Blyth, Paediatrician, Infectious Diseases Physician and Clinical Microbiologist from The University of Western Australia and Telethon Kids Institute, Professor Kristine Macartney, from University of Sydney, Professor Allen Cheng, from Monash University, and Professor Julie Leask, from University of Sydney, originally appeared in The Conversation on December 22.įormer federal MP Dr Kerryn Phelps has talked this week about the medical problems she and her wife had after their COVID-19 vaccinations around 18 months ago.
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