Neurological and neuropsychological adverse effects of SARS-CoV-2 vaccines – where do we stand?

Abstract

The devastating characteristic of COVID-19 pandemic calls for immediate and effective solutions to tackle it. Vaccines seem to be the only promising and effective way to fight against the novel coronavirus – even against new mutated variants. Because of the rapid development and distribution of numerous COVID-19 vaccines in different platforms, meticulous evaluation of vaccines’ safety is more critical than ever – especially given the fact that most of the candidates have not completed the clinical phase. Therefore, to optimize the vaccines’ safety and efficacy, it is highly important to carefully report and scientifically discuss the serious adverse effects following vaccination. In this respect, we discuss different neurological and neuropsychological adverse effects of COVID-19 vaccines including demyelinating diseases, Bell’s palsy (BP), cerebrovascular complications, seizures, functional neurological disorders (FNDs), and some other rare adverse events, and hypothetical mechanisms which can lead to the reported side effects. Given the fact that the incidence of such events are rare and most of them are treatable, the current review aims to shed light on how much the relationship between COVID-19 vaccines and these complications can be reliable and provide an insight for future studies with much more meticulous methodologies to discuss the possible correlational or causal relationship between these complications and COVID-19 vaccines and elucidate whether or not the neurological side effects of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines can count as a considerable threat to public health.

Incidence and clinical characteristics of adverse neurological events and stroke-like syndrome associated with immune stress-related response after COVID-19 vaccination in 2021 from Thailand

“…The current study revealed that most neurological AEFIs were more common in female with dyslipidemia, hypertension and diabetes mellitus in all three vaccine types, this finding is consistent with Dutch study which reported two-fold higher odds of having any AEFI as compared to males with most pronounced differences after the first dose and for nausea and injection site inflammation [10] . The most frequent clinical complaints of neurological AEFIs were numbness, headache and dizziness which are usually mild, short-duration, and self-limiting, similar to most studies [9] , [10] , [11] , [12] , [13] . Neurological AEFIs can be presented as the sole complaint or co-occurring with systemic AEFIs.…”

“…Bell’s palsy risk is slightly higher but the causality is not certain [16] . From most studies [11] , [12] , [13] , [14] , [15] , [16] , only a few serious neurological AEFIs occurred and were reported in isolated case reports or small case series. Many triggers coexist with vaccination which may lead to some serious neurological AEFIs.…”

“…Functional neurological disorder (FND, also known as conversion disorder was proposed to be the cause of this syndrome. High anxiety, abnormal beliefs and psychological stressors during the initial COVID epidemic can trigger or arouse the attention toward the body and lead to unexplained neurological symptoms [11] .…”

Safety after BBIBP-CorV (Sinopharm) COVID-19 Vaccine in Adolescents Aged 10–17 Years in Thailand

“…However, a previous study described that in febrile cases, the vaccine merely triggers seizures in patients with underlying genetic or structural defects [ 39 ]. In addition, seizures after COVID-19 vaccination commonly occur with other neurological conditions such as cerebral venous sinus thrombosis or vaccine-induced encephalopathy [ 40 ]. Given that our patient did not have neurological symptoms other than seizures, we could not conclude that the symptom was vaccine-related.…”

A bibliometric analysis of COVID-19 publications in neurology by using the visual mapping method

“…David Garcia-Azorin focuses on post-pandemic neurological syndromes (e.g., persistent headache ( 38 , 39 ) and insomnia ( 40 )). Nima Rezaei first mainly focused on neurological complications of COVID-19 ( 41 , 42 ) and then shifted to the neurological side effects of COVID-19 vaccination ( 43 ). Henrik Zetterberg focused on exploring potential neurochemical biomarkers and underlying mechanisms of COVID-19-related neuropathy ( 44 – 46 ), Tom Solomon was the most cited author because he published two articles in Lancet Neurology ( 3 ) and Lancet Psychiatry ( 5 ) that give readers a comprehensive understanding of the neurological and neuropsychiatric complications of COVID-19.…”