Guillain-Barré syndrome. Credit: UCL
A correlation between a very first dosage of the AstraZeneca vaccine and a little however significant increase in cases of the severe neurological condition Guillain-Barré syndrome, has been recognized by University College London scientists, as part of an analysis of United Kingdom National Health Service (NHS) information.
Researchers, however, say it stays unclear what the reason for the link is. The small numbers of Guillain-Barré syndrome (GBS) cases observed appear similar to boosts previously seen in other mass vaccination campaigns.
The exact same research group, based at University College London (UCL) Queen Square Institute of Neurology, had previously revealed there was no quantifiable link between COVID-19 infection and GBS. This subsequent study set out to examine any relationship between COVID-19 vaccination and GBS.
Guillain-Barré syndrome (GBS) is a rare however major autoimmune condition that assaults the peripheral worried system, generally resulting in weak point, tingling, and pain in the limbs and often leading to paralysis of breathing. GBS often happens after infections, especially a gastroenteritis infection called Camplylobacter, with the immune system incorrectly assaulting nerves instead of germs.
GBS is usually reversible, however in severe cases, it can trigger prolonged paralysis involving breathing muscles, require ventilator assistance and often leave long-term neurological deficits. Early detection by professional neurologists is key to proper treatment.
For the research, published in the journal Brain, scientists brought out a population-based research study of NHS information in England to track GBS case rates against vaccination rollout. Even more, as part of a separate study of UK healthcare facilities security data, they looked at phenotypes (characteristics/symptoms) of reported GBS cases to identify whether there were any particular functions of COVID-19 vaccine-associated GBS.
UK context and analysis
In the UK, the Pfizer COVID-19 vaccine (tozinameran) was presented in December 2020, followed by AstraZeneca (ChAdOx1 nCoV-19) in January 2021, then Moderna (mRNA-1273) in April 2021.
Researchers observed that in between January to October 2021, 996 GBS cases were recorded in the UK National Immunoglobulin Database, but with an uncommon spike in GBS reports occurring between March and April 2021. For these two months there were about 140 cases monthly compared to historical rates of about 100 each month.
To determine whether any or all of these cases were linked to vaccination, they linked dates of GBS start to vaccination receipt data held on the National Immunisation Management System in England for each individual.
The analysis exposed 198 GBS cases (20% of 966) occurred within six weeks of the first-dose COVID-19 vaccination in England, corresponding to 0.618 cases per 100,000 vaccinations. Of these, 176 individuals had actually had an AstraZeneca vaccination, 21 Pfizer, and 1 (one) Moderna. Just 23 GBS cases were reported within six weeks of any 2nd vaccine dose.
Overall, following a very first dose AstraZeneca vaccine there were 5.8 excess GBS cases per million doses of vaccine, corresponding to an absolute overall excess in between January-July 2021 of in between 98-140 cases. First-dose Pfizer and Moderna and second-dose of any vaccination revealed no excess GBS threat.
Discussing the figures, lead author Professor Michael Lunn (UCL Queen Square Institute of Neurology) said: “Higher numbers of cases of GBS are seen in the period of two to four weeks after vaccination. A peak of cases observed around 24 days following a first dosage.
” First dosages of AstraZeneca vaccine represent the majority or all of this boost. A comparable pattern is not seen with the other vaccines or following a 2nd dose of any vaccine.”
In the separate phenotype research study, researchers utilized a multi-center UK-wide (four nations) healthcare facility dataset, to gather event information on GBS cases reported by clinicians in between January 2021 and November 2021. Concluding this analysis, scientists discovered no particular clinical features, including facial weakness (which has actually gotten unique attention in medical literature), were associated with vaccination-related GBS compared to non-vaccinated cases revealing how challenging it is to spot vaccination connected cases from the background cases happening usually.
Professor Lunn stated: “The factor for the association in between only AstraZeneca vaccination and GBS is uncertain. COVID-19 infection does not have a strong, or potentially any, increased danger of GBS, and the absence of increased danger associated with Pfizer vaccination indicates that it is not likely that the COVID-19 spike protein is the causative factor for the increased threat. The viral vector used to bring the nucleic acid in the AstraZeneca and similar vaccines may be the factor but this requires even more expedition.”
Historical context of vaccine-associated GBS
Throughout the 1976 swine flu vaccination project in the USA, there was a small increase in GBS connected with what was an unique influenza jab at that time. At the time, the vaccination project was stopped since the risk of establishing GBS was statistically increased from background (regular times), although subsequent statistical analysis found the threat of a link to be lower than at first believed.
The excess occurrence following AstraZeneca initially dose vaccine is approximated to be 5.8 cases per million doses, comparable to the estimates for the 1976 swine influenza vaccine and higher (but within the same order of magnitude) as the reported excess cases for the contemporary influenza and yellow fever vaccines. It is far listed below the one in 1,000 rate of GBS related to Campylobacter jejuni gastroenteritis or Zika-virus.
Teacher Lunn included: “At the moment we do not understand why a vaccine may trigger these extremely small rises in GBS.
” It may be that a non-specific immune activation in vulnerable people happens, but if that held true similar dangers may use to all vaccine types.
” It is, for that reason, logical to suggest that the simian adenovirus vector, frequently utilized to establish vaccines, including AstraZenecas, may represent the increased threat.
” Adenoviruses have actually not been highly associated with GBS in previous studies, and any association between adenoviral vaccination and GBS has just once been reported. “Nevertheless, adenovirus screening is not routinely performed in cases of GBS in the UK, and whether adenoviruses may account for a proportion of idiopathic (no known cause) or SARS-CoV-2 negative GBS might be the topic for more research study.”
Referral: “COVID-19 vaccination and Guillain-Barré syndrome: analyses utilizing the National Immunoglobulin Database” by Ryan Y. S. Keh, Sophie Scanlon, Preeti Datta-Nemdharry, Katherine Donegan, Sally Cavanagh, Mark Foster, David Skelland, James Palmer, Pedro M. Machado, Stephen Keddie, Aisling S. Carr, Michael P. Lunn and BPNS/ABN COVID-19 Vaccine GBS Study Group, 18 February 2022, Brain.DOI: 10.1093/ brain/awac067.
The analysis revealed 198 GBS cases (20% of 966) happened within 6 weeks of the first-dose COVID-19 vaccination in England, relating to 0.618 cases per 100,000 vaccinations. Of these, 176 people had had an AstraZeneca vaccination, 21 Pfizer, and 1 (one) Moderna. Just 23 GBS cases were reported within six weeks of any 2nd vaccine dose.
Teacher Lunn said: “The reason for the association between just AstraZeneca vaccination and GBS is unclear. COVID-19 infection does not have a strong, or possibly any, increased threat of GBS, and the absence of increased threat associated with Pfizer vaccination suggests that it is not likely that the COVID-19 spike protein is the causative factor for the increased risk.