International researchers have linked very rare neurological, blood and heart related medical conditions to COVID-19 vaccines by using big data to better understand and monitor vaccine safety.
The research, involving Murdoch Children’s Research Institute (MCRI) and published in , has identified new and previously recognised vaccine safety signals, which highlight a potential link between a vaccine and a health condition, contributing crucial information to COVID-19 vaccine programs and for future mass vaccine rollouts.
The researchers are collaborators to the , which has used an to leverage large amounts of data to evaluate COVID-19 vaccine safety.
The largest study of its kind involved more than 99 million people from Australia, Argentina, Canada, Denmark, Finland, France, New Zealand and Scotland who received a COVID-19 vaccine.
The analysis found vaccine safety signals were warranted for myocarditis (inflammation of the heart muscle) and pericarditis (swelling of the thin sac covering the heart) after mRNA vaccines and Guillain-Barré syndrome (where the immune system attacks the nerves) and cerebral venous sinus thrombosis (a type of blood clot in the brain) after an AstraZeneca vaccine. A new signal for acute disseminated encephalomyelitis (inflammation and swelling in the brain and spinal cord) was also detected, warranting further investigation.
But the findings translated to an extremely small risk with any potential link needing to be weighed against the well-established protective benefits of vaccination against COVID-19.
An , led by MCRI, confirmed the increased risk between receiving an AstraZeneca vaccine and acute disseminated encephalomyelitis as well as transverse myelitis (spinal cord inflammation).
The study, using a dataset involving 6.8 million Australians, is the first to measure the association between AstraZeneca COVID-19 vaccination and the two neurological conditions.
Acute disseminated encephalomyelitis usually impacts young children and adolescents. However, COVID-19 vaccination in Australia was recommended from 12 years and over, with only younger children in high-risk groups encouraged to get vaccinated. mRNA vaccines are now recommended for everyone aged over five years in Australia.
More than 13.5 billion COVID-19 vaccine doses have been administered worldwide since 2020.
MCRI , who is also a co-director of the GVDN, said the size of the population in these studies increased the possibility of identifying very rare vaccine safety signals as rapidly as possible.
Image: Professor Jim Buttery
The GVDN was created in 2019 to assess vaccine effectiveness in diverse settings and to map links to serious side effects.
“There was a pressing need for comprehensive vaccine safety monitoring as very rare adverse events following COVID-19 vaccination were starting to come to light after administration to millions of people,” Professor Buttery said.
“Vast and diverse datasets can play a key role in early detection of potential vaccine safety signals or when regulatory and public health agencies need rapid assessment of an emerging safety signal. These evaluations are not only valuable early-on in large-scale vaccine deployment, but also as the vaccination program matures, especially if they can be conducted in a multi-country context.
“The findings will also help clinicians better inform their patients of the benefits and potential side effects associated with vaccines and boost public vaccine confidence.”
Publication 1: K. Faksovaa, D. Walsh, Y. Jiang, J. Griffin, A. Phillips, A. Gentile, J. C. Kwong, K. Macartney, M. Naus, Z. Grangek, S. Escolano, G. Sepulveda, A. Shetty, A. Pillsbury, C. Sullivan, Z. Naveed, NZ. Janjua, N. Giglio, J. Perälä, S. Nasreen, H. Gidding, P. Hovi, T. Vor, F. Cui, L. Deng, L.Cullen, M. Artamar, H. Lu, H. Clothier, K. Batty, J. Paynter, H. Petousis-Harris, J. Buttery, S. Black and A. Hviid. ‘COVID-19 vaccines and adverse events of special interest: A multinational Global Vaccine Data Network (GVDN) cohort study of 99 million vaccinated individuals,’ Vaccine. DOI:
Publication 2: Hannah J Morgan, Hazel J Clothier, Gonzalo Sepulveda Kattan, James H Boyd and Jim P Buttery. ‘Acute Disseminated Encephalomyelitis and Transverse Myelitis following COVID-19 vaccination – a self-controlled case series analysis,’ Vaccine. DOI:
