Stroke Among SARS-CoV-2 Vaccine Recipients in Mexico: A Nationwide Descriptive Study

Association of New-Onset Seizures With SARS-CoV-2 Vaccines: A Systematic Review and Meta-Analysis of Randomized Clinical Trials

Importance

Seizures have been reported as an adverse effect of the SARS-CoV-2 vaccine. However, no study has answered the question of whether there is any association between seizures in the general population and COVID-19 vaccination.

Objective

To evaluate the seizure incidence among SARS-CoV-2 vaccine recipients compared with those who received a placebo.

Data Sources

A systematic search of MEDLINE (via PubMed), Web of Science, Scopus, Cochrane Library, Google Scholar, review publications, editorials, letters to editors, and conference papers, along with the references of the included studies from December 2019 to July 7, 2023.

Study Selection

Randomized clinical trials (RCTs) reporting seizure incidence with SARS-CoV-2 vaccination were included.

Data Extraction and Synthesis

This study is reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses framework and used the Mantel-Haenszel method with random- and common-effect models. The risk of bias of the studies was assessed using the Cochrane assessment tool for RCTs.

Main Outcomes and Measures

The outcome of interest was new-onset seizure incidence proportion compared among (1) SARS-CoV-2 vaccine recipients and (2) placebo recipients.

Results

Six RCTs were included in the study. Results of the pooled analysis comparing the incidence of new-onset seizure between the 63 521 vaccine and 54 919 placebo recipients in the 28-day follow-up after vaccine/placebo injection showed no statistically significant difference between the 2 groups (9 events [0.014%] in vaccine and 1 event [0.002%] in placebo recipients; odds ratio [OR], 2.70; 95% CI, 0.76-9.57; P = .12; I2 = 0%, τ2 = 0, Cochran Q P = .74). Likewise, in the entire blinded-phase period after injection, with a median of more than 43 days, no significant difference was identified between the vaccine and placebo groups regarding incident new-onset seizure (13/43 724 events [0.03%] in vaccine and 5/40 612 [0.012%] in placebo recipients; OR, 2.31; 95% CI, 0.86-6.23, P = .10, I2 = 0%, τ2 = 0, Cochran Q P = .95).

Conclusions and Relevance

According to this systematic review and meta-analysis, there was no statistically significant difference in the risk of new-onset seizure incidence between vaccinated individuals and placebo recipients.

Neurovascular Adverse Effects of Sars-Cov-2 Vaccination

The global deployment of SARS-CoV-2 vaccines has been pivotal in curbing the COVID-19 pandemic, reducing morbidity and mortality associated with the virus. While most of these vaccines have demonstrated high efficacy and overall safety, emerging reports have highlighted potential neurovascular adverse effects, albeit uncommon, associated with these vaccinations. This review aims to assess and summarize the current knowledge on the neurovascular complications arising post-SARS-CoV-2 vaccination. We conducted an extensive literature review, focusing on clinical studies and case reports to identify reported neurovascular events, such as ischemic stroke, cerebral sinus venous thrombosis, intracerebral hemorrhage, pituitary apoplexy and primary CNS angiitis Despite the relative rarity of these events, their impact on affected individuals underscores the importance of ongoing surveillance, early detection, and management strategies. We aim to provide healthcare professionals with the latest evidence on neurovascular adverse effects, facilitating informed decision-making in the context of SARS-CoV-2 vaccination programs. Furthermore, we highlight areas requiring further research to understand the pathophysiology of these adverse events better and to develop targeted prevention and treatment strategies.

Neurological Disorders following COVID-19 Vaccination

Nowadays, people all over the world have been receiving different types of coronavirus disease 2019 (COVID-19) vaccines. While their effectiveness has been well recognized, various post-vaccination disorders are not fully understood. In this review, we discuss neurological disorders related to vascular, immune, infectious, and functional factors following COVID-19 vaccination, and attempt to provide neuroscientists, psychiatrists, and vaccination staff with a reference for the diagnosis and treatment of these diseases. These disorders may present as a recurrence of previous neurological disorders or new-onset diseases. Their incidence rate, host and vaccine characteristics, clinical manifestations, treatment, and prognosis differ significantly. The pathogenesis of many of them remains unclear, and further studies are needed to provide more evidence. The incidence rate of severe neurological disorders is relatively low, most of which are reversible or treatable. Therefore, the benefits of vaccination outweigh the risk of COVID-19 infection, especially among fragile populations.

Serious neurological adverse events following immunization against SARS-CoV-2: a narrative review of the literature

Amid the coronavirus disease 2019 (COVID-19) pandemic, massive immunization campaigns became the most promising public health measure. During clinical trials, certain neurological adverse effects following immunization (AEFIs) were observed; however, acceptable safety profiles lead to emergency authorization for the distribution and use of the vaccines. To contribute to pharmacovigilance and lessen the potential negative impact that vaccine hesitancy would have on immunization programs, we conducted a review of the scientific literature concerning the epidemiological data, clinical presentation, and potential mechanisms of these neurological AEFIs. There is some epidemiological evidence linking COVID-19 vaccines to cerebral venous sinus thrombosis, arterial ischemic stroke, convulsive disorder, Guillain-Barré syndrome, facial nerve palsy, and other neurological conditions. Cerebral venous sinus thrombosis has been associated with a thrombotic thrombocytopenia induced by the vaccine, similar to that induced by heparin, which suggests similar pathogenic mechanisms (likely involving antibodies against platelet factor 4, a chemokine released from activated platelets). Arterial ischemic stroke is another thrombotic condition observed among some COVID-19 vaccine recipients. Vaccine-induced convulsive disorder might be the result of structural abnormalities potentially caused by the vaccine or autoimmune mechanisms. Guillain-Barré syndrome and facial nerve palsy may also be linked to the immunization event, possibly due to immune mechanisms such as uncontrolled cytokine release, autoantibody production, or bystander effect. However, these events are mostly uncommon and the evidence for the association with the vaccine is not conclusive. Furthermore, the potential pathophysiological mechanisms remain largely unknown. Nevertheless, neurological AEFIs can be serious, life-threatening or even fatal. In sum, COVID-19 vaccines are generally safe and the risk of neurological AEFIs does not outweigh the benefits of immunization. However, early diagnosis and treatment of neurological AEFIs are of utmost importance, and both health professionals and the public should be aware of these conditions.

Neurological Considerations with COVID-19 Vaccinations

The benefits of coronavirus disease 2019 (COVID-19) vaccination significantly outweigh its risks on a public health scale, and vaccination has been crucial in controlling the spread of SARS-CoV-2. Nonetheless, several reports of adverse events following vaccination have been published.To summarize reports to date and assess the extent and quality of evidence regarding possible serious adverse neurological events following COVID-19 vaccination, focusing on Food and Drug Administration (FDA)-approved vaccines in the United States (BNT162b2, mRNA-1273, and Ad26.COV2.S).A review of literature from five major electronic databases (PubMed, Medline, Embase, Cochrane Library, and Google Scholar) was conducted between December 1, 2020 and June 5, 2022. Articles included in the review were systematic reviews and meta-analysis, cohort studies, retrospective studies, case-control studies, case series, and reports. Editorials, letters, and animal studies were excluded, since these studies did not include quantitative data regarding adverse side effects of vaccination in human subjects.Of 149 total articles and 97 (65%) were case reports or case series. Three phase 3 trials initially conducted for BNT162b2, MRNA-1273, and Ad26.COV2.S were included in the analysis.The amount and quality of evidence for possible neurological adverse events in the context of FDA-approved COVID-19 vaccinations is overall low tier. The current body of evidence continues to suggest that COVID-19 vaccinations have a high neurological safety profile; however, the risks and benefits of vaccination must continue to be closely monitored.

A China-developed adenovirus vector-based COVID-19 vaccine: review of the development and application of Ad5-nCov

INTRODUCTION

The global spread of COVID-19 has prompted the development of vaccines. A recombinant adenovirus type-5 vectored COVID-19 vaccine (Ad5-nCoV) developed by Chinese scientists has been authorized for use as a prime and booster dose in China and several other countries.

AREAS COVERED

We searched published articles as of 4 May 2023, on PubMed using keywords related to Adenovirus vector, vaccine, and SARS-CoV-2. We reported the progress and outcomes of Ad5-nCov, including vaccine efficacy, safety, immunogenicity based on pre-clinical trials, clinical trials, and real-world studies for primary and booster doses.

EXPERT OPINION

Ad5-nCoV is a significant advancement in Chinese vaccine development technology. Evidence from clinical trials and real-world studies has demonstrated well-tolerated, highly immunogenic, and efficacy of Ad5-nCoV in preventing severe/critical COVID-19. Aerosolized Ad5-nCoV, given via a novel route, could elicit mucosal immunity and improve the vaccine efficacy, enhance the production capacity and availability, and reduce the potential negative impact of preexisting antibodies. However, additional research is necessary to evaluate the long-term safety and immunogenicity of Ad5-nCoV, its efficacy against emerging variants, its effectiveness in a real-world context of hybrid immunity, and its cost-effectiveness, particularly with respect to aerosolized Ad5-nCoV.

Acute Arterial Ischemic Stroke Following COVID-19 Vaccination: A Systematic Review and Meta-analysis

BACKGROUND AND OBJECTIVES

Acute arterial ischemic stroke (AIS) has been reported as a rare adverse event following coronavirus disease 2019 (COVID-19) vaccination with messenger RNA (mRNA) or viral vector vaccines. However, data are sparse regarding the risk of postvaccination AIS and its potential association with thrombotic-thrombocytopenia syndrome (TTS).

METHODS

A systematic review and meta-analysis of randomized controlled clinical trials (RCTs), pharmacovigilance registries, registry-based studies, observational cohorts, and case-series was performed with the aim to calculate the following: (1) the pooled proportion of patients presenting with AIS following COVID-19 vaccination; (2) the prevalence of AIS after mRNA and vector-based vaccination; and (3) the proportion of TTS among postvaccination AIS cases. Patient characteristics were assessed as secondary outcomes.

RESULTS

Two RCTs, 3 cohort studies, and 11 registry-based studies comprising 17,481 AIS cases among 782,989,363 COVID-19 vaccinations were included in the meta-analysis. The pooled proportion of AIS following exposure to any COVID-19 vaccine type was 4.7 cases per 100,000 vaccinations (95% CI 2.2-8.1; I 2 = 99.9%). The pooled proportion of AIS following mRNA vaccination (9.2 cases per 100,000 vaccinations; 95% CI 2.5-19.3; I 2 = 99.9%) did not differ compared with adenovirus-based vaccination (2.9 cases per 100,000 vaccinations; 95% CI 0.3-7.8; I 2 = 99.9%). No differences regarding demographics were disclosed between patients with AIS following mRNA-based or vector-based vaccination. The pooled proportion of TTS among postvaccination AIS cases was 3.1% (95% CI 0.7%-7.2%; I 2 = 78.8%).

DISCUSSION

The pooled proportion of AIS following COVID-19 vaccination is comparable with the prevalence of AIS in the general population and much lower than the AIS prevalence among severe acute respiratory syndrome coronavirus 2-infected patients. TTS is very uncommonly reported in patients with AIS following COVID-19 vaccination.

Psychological and Psychiatric Events Following Immunization with Five Different Vaccines against SARS-CoV-2

Background: Despite the high number of vaccines administered against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) worldwide, the information on the psychological/psychiatric adverse events following immunization (AEFI) with these newly developed vaccines remains scarce. Objective: To describe the frequency of psychological/psychiatric symptoms among recipients of five different anti-SARS-CoV-2 vaccines and to explore the factors associated with their development reported in the nationwide Mexican registry of AEFI against SARS-CoV-2. Methods: Descriptive study of all the psychological/psychiatric symptoms, including anxiety, panic attacks, insomnia, and agitation reported to the Mexican Epidemiological Surveillance System from 21 December 2020 to 27 April 2021, among adult (≥18 years old) recipients of 7,812,845 doses of BNT162b2, ChAdOx1 nCov-19, rAd26-rAd5, Ad5-nCoV, or CoronaVac. The factors associated with their development are determined by multivariate regression analysis. Results: There were 19,163 AEFI reports during the study period; amongst them, 191 (1%) patients had psychological/psychiatric symptoms (median age of 41 years, interquartile range of 32–54; 149 [78%] women) for an observed incidence of 2.44 cases per 100,000 administered doses (95% confidence interval [CI] 2.12–2.82), 72.8% of psychiatric AEFIs were reported among recipients of BNT162b2. The median time from vaccination to symptom onset was 35 min (interquartile range: 10–720). Overall, the most common psychological/psychiatric symptoms were anxiety in 129 (67.5%) patients, panic attacks in 30 (15.7%), insomnia in 25 (13%), and agitation in 11 (5.7%). After adjusting for the confounding factors, the odds for developing psychological/psychiatric symptoms were higher for those concurrently reporting syncope (odds ratio [OR]: 4.73, 95% CI: 1.68–13.33); palpitations (OR: 2.47, 95% CI: 1.65–3.70), and dizziness (OR: 1.59, 95% CI: 1.10–2.28). Conclusion: In our population, psychological/psychiatric symptoms were extremely infrequent AEFIs. No severe psychiatric AEFIs were reported. Immunization stress-related responses might explain most of the detected cases.

Seizures following COVID-19 vaccination in Mexico: a nationwide observational study

The COVID‐19 pandemic led to the development and emergency approval of an array of effective vaccines against SARS‐CoV‐2. Given the relatively small number of patients included in vaccine trials, postapproval epidemiological surveillance is crucial to detect infrequent vaccine‐related adverse events. We conducted a nationwide retrospective descriptive study evaluating the incidence of seizures among recipients of SARS‐CoV‐2 vaccines in Mexico from December 24, 2020 (date of administration of first doses nationwide) to October 29, 2021. Among 81 916 351 doses of any vaccine that were administered, we documented seizures in 53 patients, of which 31 (60%) were new onset seizures. The incidence rate of seizures per million doses was highest for mRNA‐1273 (Moderna) with 2.73 per million, followed by BNT162b2 (Pfizer‐BioNTech) with 1.02 per million, and Ad5‐nCoV (CanSino) with 1.01 per million. Thus, we found that seizures following SARS‐CoV‐2 vaccination are exceedingly rare events.

Incidence of Guillain-Barré syndrome following SARS-CoV-2 immunization: Analysis of a nationwide registry of recipients of 81 million doses of seven vaccines

Background and purpose

Information on Guillain–Barré syndrome (GBS) as an adverse event following immunization (AEFI) against SARS‐CoV‐2 remains scarce. We aimed to report GBS incidence as an AEFI among adult (≥18 years) recipients of 81,842,426 doses of seven anti‐SARS‐CoV‐2 vaccines between December 24, 2020, and October 29, 2021, in Mexico.

Methods

Cases were retrospectively collected through passive epidemiological surveillance. The overall observed incidence was calculated according to the total number of administered doses. Vaccines were analyzed individually and by vector as mRNA‐based (mRNA‐1273 and BNT162b2), adenovirus‐vectored (ChAdOx1 nCov‐19, rAd26‐rAd5, Ad5‐nCoV, and Ad26.COV2‐S), and inactivated whole‐virion‐vectored (CoronaVac) vaccines.

Results

We identified 97 patients (52 males [53.6%]; median [interquartile range] age 44 [33–60] years), for an overall observed incidence of 1.19/1,000,000 doses (95% confidence interval [CI] 0.97–1.45), with incidence higher among Ad26.COV2‐S (3.86/1,000,000 doses, 95% CI 1.50–9.93) and BNT162b2 recipients (1.92/1,00,000 doses, 95% CI 1.36–2.71). The interval (interquartile range) from vaccination to GBS symptom onset was 10 (3–17) days. Preceding diarrhea was reported in 21 patients (21.6%) and mild COVID‐19 in four more (4.1%). Only 18 patients were tested for Campylobacter jejuni (positive in 16 [88.9%]). Electrophysiological examinations were performed in 76 patients (78.4%; axonal in 46 [60.5%] and demyelinating in 25 [32.8%]); variants were similar across the platforms. On admission, 91.8% had a GBS disability score ≥3. Seventy‐five patients (77.3%) received intravenous immunoglobulin, received seven plasma exchange (7.2%), and 15 (15.5%) were treated conservatively. Ten patients (10.3%) died, and 79.1% of survivors were unable to walk independently.

Conclusions

Guillain–Barré syndrome was an extremely infrequent AEFI against SARS‐CoV‐2. The protection provided by these vaccines outweighs the risk of developing GBS.