Covishield may trigger symptoms associated with an extremely rare form of neurological disorder called Guillain-Barre syndrome (GBS) in a minuscule set of individuals who were vaccinated, showed two independent reports from India and the UK.
Vaccination benefits
The authors of both reports, however, pointed out that the benefits of vaccination far outweigh such odd cases, but said clinicians should look out for such neurological conditions following the administration of the Covid-19 vaccine.
In two separate reports published in the journal
While doctors from central Kerala reported seven cases among approximately 1.2 million people who received Covishield vaccine, their Nottingham counterparts identified four cases in an area where 7 lakh people received the same AstraZeneca vaccine.
All 11 cases came up in people 10 to 22 days after they receiving the vaccination, the scientists said. GBS, an extremely rare disorder in which one’s immune system attacks the nerves in the peripheral nerve system, is known to be precipitated normally by a bacterial and viral infection. It may be recalled that a Chennai-based volunteer who participated in the clinical trials of AstraZeneca vaccine, carried out in India by Serum Institute of India, producer of Covishield, complained of somewhat similar neurological symptoms in October last year.
“If the link is causal it could be due to a cross-reactive immune response to the SARS-CoV-2 spike protein and components of the peripheral immune system,” wrote the authors of the report from UK.
“It might be causative. It is not a serious or life-threatening condition,” Dr Jonathan Evans, lead author of the the UK study, told BusinessLine.
What intrigued the scientists, however, is the fact that the newly reported cases were nearly 10 times greater than expected.
“Approximately 2-3 months after the vaccination programme commenced in India, we began to notice an uptick in the incidence of GBS in our community. All cases that presented to us during this period had almost the same clinical presentation,” said Dr Boby Varkey Maramattom, lead consultant, neurology, at Aster Medcity in Kochi. According to Dr Maramattom, the corresponding author of the paper on Kerala cases, most patients presented within a few days (usually within 1-2 weeks) of receiving the first dose of the vaccine. They were mostly women and belonged to middle to elderly age groups.
Respiratory weakness
He also said that most of the patients developed rapidly progressive and severe weakness that progressed to respiratory weakness and mechanical ventilation.
“At the time of publication, most of our patients were still disabled and in rehabilitation. Since then, we have encountered 5-6 more cases of GBS in our community with almost the same presentation. Unfortunately we could not perform viral genetic strain assessment due to cost considerations,” said Dr Maramattom.
According to Dr Maramattom, clinicians should know that GBS can occur after AstraZeneca vaccine or possibly other adeno vector viral vaccines.
“Rather than brushing away the association, it is important to report this association to the relevant health authorities. Moreover, rigorous scientific study into the mechanisms of GBS after vaccination may ultimately lead to safer vaccines,” he said.
He also said that the risks of GBS after vaccination are still very low and are eclipsed by the benefits of vaccination. Therefore, these rare side effects should not dissuade the community from the benefits of Covid vaccination.