Risk for Myocardial Infarction, Stroke, and Pulmonary Embolism Following COVID-19 Vaccines in Adults Younger Than 75 Years in France

Risk of heavy menstrual bleeding following COVID-19 vaccination: A nationwide case-control study

BACKGROUND

COVID-19 vaccination has been inconsistently associated with an increased risk of heavy menstrual bleeding in previous studies. This study aimed to assess the risk of heavy menstrual bleeding requiring hospital care following COVID-19 vaccination according to the number of doses received and the time elapsed since vaccination.

METHODS

Using comprehensive data of the French National Health Data System, we carried out a case-control study. Non-pregnant 15-50 years old women who had a hospital discharge diagnosis of heavy menstrual bleeding between May 12, 2021, and August 31, 2022 (cases) were randomly matched to up to 30 controls of same age, place of residence, social deprivation index, and contraceptive use profile at the date of case hospital admission (index date). Conditional logistic regression models were used to estimate the risk of hospital care for heavy menstrual bleeding associated with primary or booster doses and delay since last COVID-19 vaccination at index date, adjusting for socio-demographic characteristics, comorbidities, healthcare use indicators, and recent SARS-CoV-2 infection.

RESULTS

A total of 4610 cases and 89,375 matched controls were included (median age, 42 years). Compared to unvaccinated women, the risk of hospital care for heavy menstrual bleeding was increased in those having received a last dose of primary vaccination in the preceding 1-3 months (Odds Ratio, 1.20 [95% confidence interval, 1.07-1.35]). This association was marked among women residing in the most deprived municipalities (1.28 [1.07-1.52]) and those who were not using hormonal contraception (1.28 [1.11-1.48]). Assuming a causal relationship, a total of 103 cases [54-196] were estimated to be attributable to primary vaccination in France.

CONCLUSION

These findings provide evidence of an increased risk of heavy menstrual bleeding during the three-month period following primary COVID-19 mRNA vaccination. No increased risk was found beyond 3 months after primary vaccination nor following booster doses.

Risk of major adverse cerebro-cardiovascular events following BNT162b2, CoronaVac, and ChAdOx1 vaccination and SARS-CoV-2 infection: A self-controlled case-series study

OBJECTIVE

To assess the potential risk of major adverse cerebro-cardiovascular events (MACCE) associated with COVID-19 vaccination and SARS-CoV-2 infection.

METHODS

This self-controlled case series study used nationwide health database from Malaysia. The study included individuals aged ≥18 years who were hospitalised between 24 February 2021 and 30 June 2022. Outcomes were composite of MACCE: stroke, acute ischaemic heart disease, and cardiovascular death. Exposures were COVID-19 vaccination and SARS-CoV-2 infection. The risk period was day 1 to day 21 following exposure. Conditional Poisson regression model was used to estimate the incidence rate ratios (IRRs) and 95 % confidence interval (CI) comparing the outcomes in the risk and control periods.

RESULTS

The risk of MACCE within 21 days after vaccination per 100,000 doses administered were 12.0 (95% CI 11.9-12.1) (BNT162b2), 9.2 (95% CI 9.1-9.3) (CoronaVac), and 6.8 (95% CI 6.6-7.0) (ChAdOx1). The incidence rate ratios showed no increased risk of MACCE associated with the first, second, or third doses of BNT162b2, CoronaVac, and ChAdOx1 vaccines for individuals without prior cardiovascular disease (CVD). This finding was consistent for individuals with CVD. Vaccine booster dose, whether in a homologous or heterologous schedule, did not show increased risk of MACCE. Analysis by ethnic groups detected a slightly elevated risk of MACCE in Indian after the first dose of ChAdOx1 (IRR 1.64; 95% CI 1.08-2.48) in those without CVD. No significant association were observed in other subgroup analyses. SARS-CoV-2 infection was associated with significantly increased risk of MACCE in individuals without CVD (IRR 3.54; 95% CI 3.32-3.76) and with CVD (IRR 1.98; 95% CI 1.61-2.34).

CONCLUSIONS

Our findings support the favourable safety profile of these COVID-19 vaccines and indicate that the overall benefit-risk ratio of the COVID-19 vaccines remains positive.

The Ambivalence of Post COVID-19 Vaccination Responses in Humans

The Coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), has prompted a massive global vaccination campaign, leading to the rapid development and deployment of several vaccines. Various COVID-19 vaccines are under different phases of clinical trials and include the whole virus or its parts like DNA, mRNA, or protein subunits administered directly or through vectors. Beginning in 2020, a few mRNA (Pfizer-BioNTech BNT162b2 and Moderna mRNA-1273) and adenovirus-based (AstraZeneca ChAdOx1-S and the Janssen Ad26.COV2.S) vaccines were recommended by WHO for emergency use before the completion of the phase 3 and 4 trials. These vaccines were mostly administered in two or three doses at a defined frequency between the two doses. While these vaccines, mainly based on viral nucleic acids or protein conferred protection against the progression of SARS-CoV-2 infection into severe COVID-19, and prevented death due to the disease, their use has also been accompanied by a plethora of side effects. Common side effects include localized reactions such as pain at the injection site, as well as systemic reactions like fever, fatigue, and headache. These symptoms are generally mild to moderate and resolve within a few days. However, rare but more serious side effects have been reported, including allergic reactions such as anaphylaxis and, in some cases, myocarditis or pericarditis, particularly in younger males. Ongoing surveillance and research efforts continue to refine the understanding of these adverse effects, providing critical insights into the risk-benefit profile of COVID-19 vaccines. Nonetheless, the overall safety profile supports the continued use of these vaccines in combating the pandemic, with regulatory agencies and health organizations emphasizing the importance of vaccination in preventing COVID-19's severe outcomes. In this review, we describe different types of COVID-19 vaccines and summarize various adverse effects due to autoimmune and inflammatory response(s) manifesting predominantly as cardiac, hematological, neurological, and psychological dysfunctions. The incidence, clinical presentation, risk factors, diagnosis, and management of different adverse effects and possible mechanisms contributing to these effects are discussed. The review highlights the potential ambivalence of human response post-COVID-19 vaccination and necessitates the need to mitigate the adverse side effects.

Influence of mRNA Covid-19 vaccine dosing interval on the risk of myocarditis

Myocarditis is the most salient serious adverse event following messenger RNA-based Covid-19 vaccines. The highest risk is observed after the second dose compared to the first, whereas the level of risk associated with more distant booster doses seems to lie in between. We aimed to assess the relation between dosing interval and the risk of myocarditis, for both the two-dose primary series and the third dose (first booster). This matched case-control study included 7911 cases of myocarditis aged 12 or more in a period where approximately 130 million vaccine doses were administered. Here we show that longer intervals between each consecutive dose, including booster, may decrease the occurrence of vaccine-associated myocarditis by up to a factor of 4, especially under age 50. These results suggest that a minimum 6-month interval might be required when scheduling additional booster vaccination.

Thromboembolism after coronavirus disease 2019 vaccination in atrial fibrillation/flutter: a self-controlled case series study

BACKGROUND AND AIMS

Concerns about the safety of coronavirus disease 2019 (COVID-19) vaccines in patients with atrial fibrillation/flutter (AF/AFL) have arisen due to reports of thrombo-embolic events following COVID-19 vaccination in the general population. This study aimed to evaluate the risk of thrombo-embolic events after COVID-19 vaccination in patients with AF/AFL.

METHODS

This was a modified self-controlled case-series study using a comprehensive nationwide-linked database provided by the National Health Insurance Service in South Korea to calculate incidence rate ratios (IRRs) of thrombo-embolic events. The study population included individuals aged ≥12 years who were either vaccinated (e.g. one or two doses) or unvaccinated during the period from February to December 2021. The primary outcome was a composite of thrombo-embolic events, including ischaemic stroke, transient ischaemic attack, and systemic thromboembolism. The risk period was defined as 0-21 days following COVID-19 vaccination.

RESULTS

The final analysis included 124 127 individuals with AF/AFL. The IRR of thrombo-embolic events within 21 days after COVID-19 vaccination, compared with that during the unexposed control period, was 0.93 [95% confidence interval (CI) 0.77-1.12]. No significant risk variations were noted by sex, age, or vaccine type. However, patients without anticoagulant therapy had an IRR of 1.88 (95% CI 1.39-2.54) following vaccination.

CONCLUSIONS

In patients with AF/AFL, COVID-19 vaccination was generally not associated with an increased risk of thrombo-embolic events. However, careful individual risk assessment is required when advising vaccination for those not on oral anticoagulant, as these patients exhibited an increased risk of thrombo-embolic events post-vaccination.

Cardiac Adverse Events and Remdesivir in Hospitalized Patients With COVID-19: A Post Hoc Safety Analysis of the Randomized DisCoVeRy Trial

BACKGROUND

We aimed to evaluate the cardiac adverse events (AEs) in hospitalized patients with coronavirus disease 2019 (COVID-19) who received remdesivir plus standard of care (SoC) compared with SoC alone (control), as an association was noted in some cohort studies and disproportionality analyses of safety databases.

METHODS

This post hoc safety analysis is based on data from the multicenter, randomized, open-label, controlled DisCoVeRy trial in hospitalized patients with COVID-19. Any first AE that occurred between randomization and day 29 in the modified intention-to-treat (mITT) population randomized to either remdesivir or control group was considered. Analysis was performed using Kaplan-Meier survival curves, and Kaplan-Meier estimates were calculated for event rates.

RESULTS

Cardiac AEs were reported in 46 (11.2%) of 410 and 48 (11.3%) of 423 patients in the mITT population (n = 833) enrolled in the remdesivir and control groups, respectively. The difference between both groups was not significant (hazard ratio [HR], 1.0; 95% confidence interval [CI], .7-1.5; P = .98), even when serious and nonserious cardiac AEs were evaluated separately. The majority of reports in both groups were of arrhythmic nature (remdesivir, 84.8%; control, 83.3%) and were associated with a favorable outcome. There was no significant difference between the two groups in the occurrence of cardiac AE subclasses, including arrhythmic events (HR, 1.1; 95% CI, .7-1.7; P = .68).

CONCLUSIONS

Remdesivir treatment was not associated with an increased risk of cardiac AEs compared with control in patients hospitalized with moderate or severe COVID-19. These results are consistent with other randomized, controlled trials and meta-analyses. Clinical Trials Registration. NCT04315948; EudraCT 2020-000936-23.

Association between COVID-19 Vaccination (ChAdOx1-S) and Thromboembolic, Thrombocytopenic, Hemorrhagic Events: A Systematic Review and Meta-analysis of Analytical Epidemiological Studies

We conducted a systematic review of analytical epidemiological studies to assess the association between ChAdOx1-S vaccination and thromboembolic, thrombocytopenic, and hemorrhagic events. We searched Medline, Embase, Google Scholar, WHO-COVID-19 database, and medRxiv for studies evaluating the association between ChAdOx1-S and vascular events. Primary outcomes of interest were cerebral venous sinus thrombosis, peripheral venous thrombosis (PVT), and thrombocytopenia. Two independent reviewers screened for eligible studies, extracted data, and assessed the risk of bias. The DerSimonian-Laird random effects model was used to pool the incidence rate ratios (IRRs) separately for the first and second doses. Heterogeneity was assessed using I2 statistics. Twenty studies were included, of which 11 were self-controlled case series, and nine were cohort studies (254 million participants). Pooling of 17 studies showed a higher risk of cerebrovascular thrombosis (IRR = 3.5, 95% CI = 2.2-5.4, I2 = 79%), PVT (IRR = 2.0, 95% CI = 1.1-3.5, I2 = 95%) and thrombocytopenia (IRR = 1.6, 95% CI = 1.4-1.9, I2 = 93%) among those who received ChAdOx1-S vaccination as compared to controls. No increased risk was seen after the second dose or for secondary outcomes. There is moderate-to-high certainty of the evidence for the increased risk of cerebral venous sinus thrombosis, PVT, and thrombocytopenia following the first dose of the ChAdOx1-S vaccine. Systematic Review Registration: PROSPERO CRD42022372768.

COVID-19 vaccination and major cardiovascular and haematological adverse events in Abu Dhabi: retrospective cohort study

The widespread administration of COVID-19 vaccines has prompted a need to understand their safety profile. This investigation focuses on the safety of inactivated and mRNA-based COVID-19 vaccines, particularly concerning potential cardiovascular and haematological adverse events. A retrospective cohort study was conducted for 1.3 million individuals residing in Abu Dhabi, United Arab Emirates, who received 1.8 million doses of the inactivated BBIBP CorV (by SinoPharm) and mRNA-based BNT162b2 (Pfizer-BioNTech) vaccines between June 1, 2021, and June 30, 2022. The study's primary outcome was to assess the occurrence of selected cardiovascular and haematological events leading to hospitalization or emergency room visits within 21 days post-vaccination. Results showed no significant increase in the incidence rates of these events compared to the subsequent 22 to 42 days following vaccination. Analysis revealed no elevated risk for adverse outcomes following first (IRR 1·03; 95% CI 0·82-1·31), second (IRR 0·92; 95% CI 0·72-1·16) and third (IRR 0·82; 95% CI 0·66-1·00) doses of either vaccine. This study found no substantial link between receiving either mRNA and inactivated COVID-19 vaccines and a higher likelihood of cardiovascular or haematological events within 21 days after vaccination.

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.

Prior COVID-19 vaccination and reduced risk of cerebrovascular diseases among COVID-19 survivors

The effects of COVID-19 vaccination on short-term and long-term cerebrovascular risks among COVID-19 survivors remained unknown. We conducted a national multi-center retrospective cohort study with 151 597 vaccinated and 151 597 unvaccinated COVID-19 patients using the TriNetX database, from January 1, 2020 to December 31, 2023. Patients baseline characteristics were balanced with propensity score matching (PSM). The outcomes were incident cerebrovascular diseases occurred between 1st and 30th days (short-term) after COVID-19 diagnosis. Nine subgroup analyses were conducted to explore potential effect modifications. We performed six sensitivity analyses, including evaluation of outcomes between 1st to 180th days, accounting for competing risk, and incorporating different variant timeline to test the robustness of our results. Kaplan-Meier curves and Log-Rank tests were performed to evaluate survival difference. Cox proportional hazards regressions were adopted to estimate the PSM-adjusted hazard ratios (HR). The overall short-term cerebrovascular risks were lower in the vaccinated group compared to the unvaccinated group (HR: 0.66, 95% CI: 0.56-0.77), specifically cerebral infarction (HR: 0.62, 95% CI: 0.48-0.79), occlusion and stenosis of precerebral arteries (HR: 0.74, 95% CI: 0.53-0.98), other cerebrovascular diseases (HR: 0.57, 95% CI: 0.42-0.77), and sequelae of cerebrovascular disease (HR: 0.39, 95% CI:0.23-0.68). Similarly, the overall cerebrovascular risks were lower in those vaccinated among most subgroups. The long-term outcomes, though slightly attenuated, were consistent (HR: 0.80, 95% CI: 0.73-0.87). Full 2-dose vaccination was associated with a further reduced risk of cerebrovascular diseases (HR: 0.63, 95% CI: 0.50-0.80) compared to unvaccinated patients. Unvaccinated COVID-19 survivors have significantly higher cerebrovascular risks than their vaccinated counterparts. Thus, clinicians are recommended to monitor this population closely for stroke events during postinfection follow-up.

Pfizer COVID19 vaccine is not associated with acute cardiovascular events excluding myocarditis- a national self-controlled case series study

BACKGROUND

Despite publications assuring no increased risk for acute cardiovascular events (excluding myocarditis) and sudden death following administration of COVID19 vaccines, these issues still stir much public ado. We assessed the risk for acute cardiovascular events that require hospitalization (excluding myocarditis) and for mortality in the short-term following administration of the second dose of the Pfizer COVID19 vaccine in Israel.

METHODS

Using a self-controlled case series (SCCS) study design and national databases, all second-dose vaccinees, who had not been diagnosed with COVID19 and who had an acute cardiovascular event (acute myocardial infarction/acute stroke/acute thromboembolic event) that required hospitalization in the 60 days following vaccine administration between Jan 11th, 2021 and Oct 31st 2021, were included. A similar analysis was carried out for mortality. The first 30 days following vaccination were defined as risk period while the next 30 days were defined as control period. The probability for an event between these periods was compared using a conditional logistic regression model, accounting for sex, age group, background morbidity and seasonal risk.

RESULTS

Out of 5,700,112  second dose vaccinees, 4,163 had an acute cardiovascular event in the 60 days following vaccine administration. Following exclusion of 106 due to technical considerations, 1,979 events occurred during the risk period and 2,078 during the control period: Odds ratio, OR = 0.95, 95% confidence interval, CI 0.90-1.01, p = 0.12. Adjusted OR was similar (OR = 0.88, 95%CI 0.72-1.08). Stratifying by age showed no increased risk in any age group. Mortality assessment indicated low number of events in both periods. These results were consistent in sensitivity analyses.

CONCLUSIONS

There was no increased risk for acute cardiovascular events (excluding myocarditis) in the risk period compared to the control period following administration of the second dose of Pfizer COVID19 vaccine. Mortality data raised no concerns either, but may have been biased.

Trends in admissions for COVID-19 in the United States between April 2020 and December 2021 and cardiovascular events

Introduction

Coronavirus disease 2019 (COVID-19) can lead to cardiovascular complications. We aimed to understand the trends in admission for COVID-19 and the incidence of various cardiovascular events.

Material and methods

The 2020 and 2021 National Inpatient Sample (NIS) was studied for cases of COVID-19 between April 2020 and December 2021 in the United States. Linear-by-linear association helped us understand the trends of various events.

Results

The number of cases of COVID-19 was highest in January 2021 (261,469 patients). The incidence of acute pulmonary embolism rose from 2.08% in April 2020 to 4.82% in November 2021, while deep vein thrombosis cases rose from 1.74% in April 2020 to 2.63% in December 2021. The incidence of cardiac arrest varied, with a maximum of 3.00% in August 2021. Similarly, acute ischemic stroke cases experienced their highest incidence in January 2021 (0.91%). The incidence of myocarditis was highest in April and May 2020 (0.42% each). Peak takotsubo cases were seen between October and December 2021. The highest overall all-cause mortality among COVID-19 cases was seen in April 2020 (16.74%).

Conclusions

Throughout the 21 months of our analysis, various trends in COVID-19 cases and incidence of cardiac events were noticed. This could relate to the different variants of COVID-19, their direct and indirect impact on coagulation pathways and the myocardial tissues, and the protective roles of the vaccines.

Persistence and safety of anti-TNF biosimilars versus originators in immune-mediated inflammatory diseases: an observational study on the French National Health Data System

OBJECTIVES

Biosimilar-originator equivalence has been demonstrated in phase 3 trials in a few indications of infliximab, etanercept and adalimumab. The objective of our study was to compare the persistence and safety of biosimilars versus originators in all the licensed indications of these molecules.

METHODS

We used data from the French National Health Data System (SNDS), covering 99% of the French population, to identify infliximab, etanercept and adalimumab initiators from biosimilar launch (January 2015, May 2016 and October 2018, respectively) to 30 June 2021. Patients were then followed for 1 year. Treatment persistence (duration without treatment discontinuation or modification) and safety (including severe infections, all-cause hospitalisation and death) were compared between originator and biosimilar users by Cox regressions weighting the populations on the inverse probability of treatment. Analyses were performed by molecule, by disease and by biosimilar product.

RESULTS

From January 2015 to June 2021, 86 776 patients were included in the study: 22 670, 24 442 and 39 664 patients had initiated infliximab, etanercept and adalimumab, respectively; 49 752 (53%) were biosimilar initiators. We did not find any risk of discontinuation (HRs were below or around 1, here all pathologies and products together: infliximab 0.88 (0.80-0.97), etanercept 0.85 (0.81-0.90) and adalimumab 0.96 (0.91-1.00)) or safety event (infection: infliximab 0.97 (0.78-1.21), etanercept 1.04 (0.81-1.33) and adalimumab 0.98 (0.83-1.16); hospitalisation: infliximab 1.08 (0.96-1.23), etanercept 0.99 (0.87-1.11) and adalimumab 0.91 (0.83-0.99)) associated with biosimilar versus originator use.

CONCLUSIONS

Our study shows reassuring results regarding the persistence and safety of biosimilar tumour necrosis factor-alpha inhibitors compared with originators in all licensed indications.

Case Study of Autopsy Findings in a Population of Post-COVID-19 Vaccination in Thailand

ABSTRACT

Thailand began offering the coronavirus disease 2019 (COVID-19) vaccine nationwide in February 2021, with 1,885 deaths reported by the end of the year. Therefore, it is essential to assess the correlation between vaccination and cause of death from autopsy. This study included 34 autopsies of a deceased within 30 days after COVID-19 vaccination performed in Bangkok under the postmortem inquest service area of Bhumibol Adulyadej Hospital. The autopsies were performed by forensic pathologists. Moreover, detailed information about the deceased was collected, including age, sex, medical records, vaccination history, scene investigation reports, autopsy reports, cause of death, and a probable causal relationship between vaccination and cause of death. There were 24 males (70.59%), and the average age of the deceased was 52.76 years. Of all individuals, 28 (82.36%), 4 (11.76%), and 2 (5.88%) were vaccinated with AstraZeneca, Sinopharm, and SinoVac, respectively. The most common cause of death was ischemic heart disease (n = 17). None of the deceased patients had a causal relationship to the vaccine. Deaths were due to natural causes, as no definitive link between vaccination and cause of death was established in the study.

The importance of COVID-19 vaccination during lactation

The World Health Organization strongly supports breastfeeding as the main source of infant feeding to ensure maternal and child health. Since its emergence, COVID-19 has become a disease affecting the health of the world's population, and vaccines have been developed to prevent it. However, the decision to license COVID-19 vaccines for infants under 6 months of age has been delayed. Different studies have shown that during the breastfeeding period, the benefit-risk balance is much higher in favor of the benefit, at the immunological level for the infant, due to its low perception of adverse effects and the low transmission of products such as mRNA from the mother to the child. Different organizations and societies recommend vaccination in breastfeeding women. COVID-19 vaccines have been shown to be safe and effective.

Association of Cardiovascular Events with COVID-19 Vaccines Using Vaccine Adverse Event Reporting System (VAERS): A Retrospective Study

BACKGROUND

COVID-19 vaccines have played a crucial role in reducing the burden of the global pandemic. However, recent case reports have indicated the association of the COVID- 19 vaccines with cardiovascular events but the exact association is unclear so far.

OBJECTIVE

Therefore, the objective of the current study is to find out the association of cardiovascular events with COVID-19 vaccines.

METHODS

The COVID-19 Vaccine Knowledge Base (Cov19VaxKB) tool was used to query the Vaccine Adverse Event Reporting System (VAERS) database. The proportional reporting ratio [PRR (≥2)] with associated chi-squared value (>4), and the number of cases > 0.2% of total reports, was used to assess the association of COVID-19 vaccines with cardiovascular events.

RESULTS

A total of 33,754 cases of cardiovascular events associated with COVID-19 vaccines were found in the Cov19VaxKB tool. The cases were observed in different age groups (18-64, and 65 years and above) and gender. The disproportionality measures indicate a statistically significant association between cardiovascular events and COVID-19 vaccines.

CONCLUSION

The current study identified a signal of various cardiovascular events with the COVID-19 vaccines. However, further causality assessment is required to confirm the association.

Risk of Guillain-Barré Syndrome Following COVID-19 Vaccines: A Nationwide Self-Controlled Case Series Study

BACKGROUND AND OBJECTIVES

Guillain-Barré syndrome (GBS) has been inconsistently associated with some coronavirus disease 2019 (COVID-19) vaccines. We aimed to quantify the risk of GBS according to the type of COVID-19 vaccine in a large population.

METHODS

Using the French National Health Data System linked to the COVID-19 vaccine database, we analyzed all individuals aged 12 years or older admitted for GBS from December 27, 2020, to May 20, 2022. We estimated the relative incidence (RI) of GBS within 1-42 days after vaccination up to the first booster dose compared with baseline periods using a self-controlled case series design. We then derived the number of cases attributable to the vaccination. Analyses were adjusted for the period and stratified by age group, sex, and for the presence of severe acute respiratory syndrome coronavirus 2 or common acute infections.

RESULTS

Of 58,530,770 people aged 12 years or older, 88.8% received at least 1 COVID-19 vaccine dose and 2,229 were hospitalized for GBS during the study period. Patients had a median age of 57 years, and 60% were male patients. The RI of GBS between 1-42 days was 2.5 (95% CI 1.8-3.6) for the first dose of ChAdOx1-S and 2.4 (95% CI 1.2-5.0) for the unique dose of Ad26.COV2.S vaccine. We estimated 6.5 attributable GBS cases per million persons having received a first dose of ChAdOx1-S and 5.7 cases per million for the Ad26.COV2.S vaccine. Except for the age group of 12-49 years after the second dose of the messenger RNA (mRNA)-1273 vaccine (RI 2.6, 95% CI 1.2-5.5), none of the RI estimates were found significantly increased for the mRNA vaccines.

DISCUSSION

In summary, we found increased risks of GBS after the first administration of ChAdOx1-S and Ad26.COV2.S vaccines. In this comprehensive assessment at the French population level, there was no statistically significant increase in the risk of GBS after the administration of mRNA vaccines. This is reassuring in the context of the ongoing and future use of mRNA-based booster vaccination.

Stroke Following Coronavirus Disease 2019 Vaccination: Evidence Based on Different Designs of Real-World Studies

BACKGROUND

We aimed to evaluate whether coronavirus disease 2019 (COVID-19) vaccination was associated with stroke.

METHODS

We conducted a systematic meta-analysis of studies using cohort, self-controlled case series (SCCS), and case-crossover study (CCOS) designs to evaluate incidence risk ratios (IRRs) and 95% confidence intervals (CIs) of ischemic stroke (IS), hemorrhagic stroke (HS), and cerebral venous sinus thrombosis (CVST) following COVID-19 vaccination. Risks of stroke were pooled among subpopulations categorized by vaccine type, dose, age, and sex. Sensitivity analysis was performed by different defined risk periods.

RESULTS

Fourteen studies involving 79 918 904 individuals were included. Cohort studies showed decreased risks of IS (IRR, 0.82 [95% CI, .75-.90]) and HS (IRR, 0.75 [95% CI, .67-.85]) postvaccination, but not CVST (IRR, 1.18 [95% CI, .70-1.98]). SCCS identified increased risks 1-21 days postvaccination (IRRIS, 1.05 [95% CI, 1.00-1.10]; IRRHS, 1.16 [95% CI, 1.06-1.26]) or 1-28 days postvaccination (IRRIS, 1.04 [95% CI, 1.00-1.08]; IRRHS, 1.37 [95% CI, 1.15-1.64]), similar to CVST (IRR, 1.58 [95% CI, 1.08-2.32]). CCOS reported an increased risk of CVST after ChAdOx1 vaccination (IRR, 2.9 [95% CI, 1.1-7.2]).

CONCLUSIONS

Although different study designs yielded inconsistent findings, considering the relatively low background incidence of stroke and benefits of vaccination, even a potentially increased risk of stroke postvaccination should not justify vaccine hesitancy.

COVID-19 Hospitalization in Solid Organ Transplant Recipients on Immunosuppressive Therapy

Importance

Solid organ transplant recipients are at high risk of severe infection with SARS-CoV-2 compared with the general population. However, factors associated with COVID-19-related severity in this population are still insufficiently explored in the literature.

Objective

To examine which health conditions and immunosuppressive drugs for preventing graft rejection are associated with the risk of COVID-19-related hospitalization in solid organ transplant recipients.

Design, Setting, and Participants

Using the French National Health Data System, this cohort study assessed patients of any age who received transplants between their date of birth and entry into the cohort on February 15, 2020. The cohort was followed up between February 15, 2020, and July 31, 2022.

Exposures

Immunosuppressive drugs, including steroids, and health conditions (age, sex, and comorbidities).

Main Outcomes and Measures

The main outcome was hospitalization for COVID-19, defined by main diagnostic International Statistical Classification of Diseases and Related Health Problems, Tenth Revision (ICD-10) codes. Factors associated with the outcome were identified with a nonconditional logistic regression. Confounding by indication was controlled using a multivariable model with adjustment for individual confounders. Each transplanted organ was examined separately.

Results

Overall, 60 456 participants (median [IQR] age, 59 [47-67] years; 63.7% male) were included in the study, of whom 41 463 (68.6%) had kidney transplants, 14 464 (23.9%) had liver transplants, 5327 (8.8%) had heart transplants, and 2823 (4.6%) had lung transplants. Among them, 12.7% of kidney transplant recipients, 6.4% of liver transplant recipients, 12.9% of heart transplant recipients, and 18.0% of lung transplant recipients were hospitalized for COVID-19. In kidney transplant recipients, steroids (adjusted odds ratio [AOR], 1.60; 95% CI, 1.49-1.73) and mycophenolic acid (AOR, 1.37; 95% CI, 1.25-1.51) were associated with a high risk of hospitalization. In liver transplant recipients, tacrolimus (AOR, 0.77; 95% CI, 0.61-0.98) was associated with a decreased risk, and steroids (AOR, 1.60; 95% CI, 1.38-1.86) and mycophenolic acid (AOR, 1.61; 95% CI, 1.37-1.90) were associated with an increased risk of hospitalizations. In heart transplant recipients, cyclosporine (AOR, 0.67; 95% CI, 0.47-0.94) was associated with a decreased risk, and steroids (AOR, 1.42; 95% CI, 1.11-1.82), mycophenolic acid (AOR, 1.29; 95% CI, 1.02-1.64), sirolimus (AOR, 2.71; 95% CI, 1.20-6.09), and everolimus (AOR, 1.24; 95% CI, 1.01-1.51) were associated with an increased risk of hospitalization. Only steroids (AOR, 1.72; 95% CI, 1.19-2.48) were associated with a high risk of COVID-19 hospitalization in lung transplant recipients.

Conclusions and Relevance

This study suggests that mycophenolic acid, sirolimus, and steroids are associated with an increased risk of COVID-19-related hospitalization in solid organ transplant recipients. These results should be considered by clinicians treating transplant recipients and may help inform epidemic-related decisions for this population in the future.

NEURO-COVAX: An Italian Population-Based Study of Neurological Complications after COVID-19 Vaccinations

OBJECTIVE

In this Italian population-based study, we aimed to evaluate the neurological complications after the first and/or second dose of COVID-19 vaccines and factors potentially associated with these adverse effects.

METHODS

Our study included adults aged 18 years and older who received two vaccine doses in the vaccination hub of Novegro (Milan, Lombardy) between 7 and 16 July 2021. The NEURO-COVAX questionnaire was able to capture the neurological events, onset and duration. That data that were digitized centrally by the Lombardy region were used to match the demographic/clinical characteristics and identify a vulnerability profile. Associations between vaccine lines and the development of complications were assessed. Digital healthcare system matching was also performed to evaluate severe neurological complications (Guillain-Barrè syndrome, Bell's palsy, transverse myelitis, encephalitis) and the incidence of hospital admissions and/or the mortality rate after two doses of the vaccines.

RESULTS

The NEURO-COVAX-cohort included 19.108 vaccinated people: 15.368 with BNT162b2, 2077 with mRNA-1273, 1651 with ChAdOx1nCov-19, and 12 with Ad26.COV2.S who were subsequently excluded. Approximately 31.2% of our sample developed post-vaccination neurological complications, particularly with ChAdOx1nCov-19. A vulnerable clinical profile emerged, where over 40% of the symptomatic people showed comorbidities in their clinical histories. Defining the neurological risk profile, we found an increased risk for ChAdOx1nCov-19 of tremors (vs. BNT162b2, OR: 5.12, 95% CI: 3.51-7.48); insomnia (vs. mRNA-1273, OR: 1.87, 95% CI: 1.02-3.39); muscle spasms (vs. BNT162b2, OR: 1.62, 95% CI: 1.08-2.46); and headaches (vs. BNT162b2, OR: 1.49, 95% CI: 0.96-1.57). For mRNA-1273, there were increased risks of parethesia (vs. ChAdOx1nCov-19, OR: 2.37, 95% CI: 1.48-3.79); vertigo (vs. ChAdOx1nCov-19, OR: 1.68, 95% CI: 1.20-2.35); diplopia (vs. ChAdOx1nCov-19, OR: 1.55, 95% CI: 0.67-3.57); and sleepiness (vs. ChAdOx1nCov-19, OR: 1.28, 95% CI: 0.98-1.67). In the period that ranged from March to August 2021, no one was hospitalized and/or died of severe complications related to COVID-19 vaccinations.

DISCUSSION

This study estimates the prevalence and risk for neurological complications potentially associated with COVID-19 vaccines, thus improving the vaccination guidelines and loading in future personalized preventive medicine.

RAndomized Clinical Trial Of NAfamostat Mesylate, A Potent Transmembrane Protease Serine 2 (TMPRSS2) Inhibitor, in Patients with COVID-19 Pneumonia

Even though SARS-CoV-2 was declared by WHO as constituting no longer a public health emergency, the development of effective treatments against SARS-CoV-2 infection remains a critical issue to prevent complications, particularly in fragile patients. The protease inhibitor nafamostat, currently used in Japan and Korea for pancreatitis, owing to its anticoagulant properties for disseminated intravascular coagulation (DIC), is appealing for the treatment of COVID-19 infection, because it potently inhibits the transmembrane protease serine 2 (TMPRSS2) that, after virus binding to ACE-2, allows virus entry into the cells and replication. Moreover, it could prevent the DIC and pulmonary embolism frequently associated with COVID-19 infection. The goal of the RAndomized Clinical Trial Of NAfamostat (RACONA) study, designed as a prospective randomized, double-blind placebo-controlled clinical trial, was to investigate the efficacy and safety of nafamostat mesylate (0.10 mg/kg/h iv for 7 days), on top of the optimal treatment, in COVID-19 hospitalized patients. We could screen 131 patients, but due to the predefined strict inclusion and exclusion criteria, only 15 could be randomized to group 1 (n = 7) or group 2 (n = 8). The results of an ad interim safety analysis showed similar overall trends for variables evaluating renal function, coagulation, and inflammation. No adverse events, including hyperkalemia, were found to be associated with nafamostat. Thus, the RACONA study showed a good safety profile of nafamostat, suggesting that it could be usefully used in COVID-19 hospitalized patients.

Individual trigger factors for hemorrhagic stroke: Evidence from case-crossover and self-controlled case series studies

BACKGROUND

Hemorrhagic stroke (HS) is a sudden-onset disease with high mortality and disability rates, and it is crucial to explore the triggers of HS. In this study, we analyzed individual triggers for HS to provide a basis for HS prevention and intervention.

METHODS

A systematic search of five databases was conducted until December 2022. Studies on HS-related individual triggers conducted using a case-crossover study or self-controlled case series design were included in the descriptive summary and comprehensive evidence synthesis of each trigger.

RESULTS

A total of 39 studies were included after the screening, and 32 trigger factor categories were explored for associations. Potential trigger factors for HS were as follows: Antiplatelet (odd ratio (OR), 1.10; 95% confidence interval (CI), 1.00-1.21) and anticoagulant (OR, 5.43; 95% CI, 2.04-14.46) medications, mood stabilizers/antipsychotics (OR, 1.33; 95% CI, 1.07-1.65), infections (OR, 2.15; 95% CI, 1.73-2.67), vaccinations (relative risk, 1.11; 95% CI, 1.02-1.21), physical exertion (OR, 2.08; 95% CI, 1.58-2.74), cola consumption (OR, 5.45; 95% CI, 2.76-10.76), sexual activity (OR, 7.49; 95% CI, 2.23-25.22), nose blowing (OR range, 2.40-56.40), defecation (OR, 16.94; 95% CI, 3.40-84.37), and anger (OR, 3.59; 95% CI, 1.56-8.26). No associations were observed with illicit drug use (OR, 2.05; 95% CI, 0.52-8.06) or cigarette smoking (OR, 0.81; 95% CI, 0.52-1.24) and HS.

CONCLUSIONS

Individual triggers, including several medications, infections, vaccinations, and behaviors, may trigger HS onset. Direct control measures for behavioral triggers can play a crucial role in preventing HS. High-risk populations should receive personalized therapies and monitoring measures during the medication treatment to balance the risk of acute HS and the basic diseases.

Impact of coronavirus disease 2019 on contraception use in France

To limit the spread of the coronavirus disease 2019 (COVID 19), sanitary restrictions have been established since March 2020 in France. These restrictions and the waves of contamination may have had consequences on the use of health products in general, and on the use of contraceptives in particular. We aimed to assess the impact of COVID 19 pandemic from March 16th 2020 to April 30th 2021 in France on reimbursed contraceptives. We analyzed data from the French national health insurance database (SNDS) by extracting all oral contraception (OC), emergency contraception (EC), levonorgestrel-intrauterine system (LNG-IUS), copper-intrauterine device (C-IUD) and contraceptive implant dispensations in 2018, 2019, 2020 and to April 30th 2021. We computed the expected use of contraceptives in 2020 and 2021 without pandemic and its associated sanitary restrictions, by taking the annual trend into account. We assessed the evolution of dispensations by type of contraceptive and by age-groups (≤25 years old, between 25 and 35 and >35 years old) between observed and expected dispensations. After 15 months of pandemic, a decrease of all reimbursed contraceptives dispensations had been estimated, compared with what was expected: -2.0% for OC, -5.0% for EC, -9.5% for LNG-IUS, -8.6% for C-IUD, -16.4% for implant. Women under 25 years old were the most impacted by the decrease. This national study showed that the impact of the COVID 19 crisis was global on all reimbursed contraceptives, with different levels of impact depending on the type of contraceptive, the age-group and the severity of the restriction. OC dispensing decreased marginally compared with expectations. The decrease in long-acting contraceptives dispensing was more pronounced, especially for the implant. These results call for continued monitoring of contraceptive use over the long term and for prioritizing access to sexual health services during crises, especially among the youngest women who were most affected in this study.

Contribution of real-life studies in France during the COVID-19 pandemic and for the national pharmaco-epidemiological surveillance of COVID-19 vaccines

During the COVID-19 pandemic, EPI-PHARE, a scientific group in pharmaco-epidemiology created by the French National Agency for the Safety of Medicines and Health Products (ANSM) and the French National Health Insurance (Cnam), has reoriented its work program to enlighten health authorities in this health crisis. By exploiting massive and complex data of the French Health Data System (SNDS) from the beginning of the first lockdown in France in March 2020, we were able to publish numerous results on the use, benefits and risks of medicines, on the risk factors of COVID-19 before and after vaccination, and on the benefits and risks of COVID-19 vaccines. Our results were widely taken into account by the French health authorities and allowed them to take informed decision in this pandemic situation in order to ensure the health of the population.

Distinct Features of Vascular Diseases in COVID-19

The Coronavirus Disease 2019 (COVID-19) pandemic was declared in early 2020 after several unexplained pneumonia cases were first reported in Wuhan, China, and subsequently in other parts of the world. Commonly, the disease comprises several clinical features, including high temperature, dry cough, shortness of breath, and hypoxia, associated with findings of interstitial pneumonia on chest X-ray and computer tomography. Nevertheless, severe forms of acute respiratory syndrome-related coronavirus 2 (SARS-CoV-2) are not limited to the respiratory tract but also may be extended to other systems, including the cardiovascular system. The bi-directional relationship between atherosclerosis and COVID-19 is accompanied by poor prognosis. The immune response hyperactivation due to SARS-CoV-2 infection causes an increased secretion of cytokines, endothelial dysfunction, and arterial stiffness, which promotes the development of atherosclerosis. Also, due to the COVID-19 pandemic, access to healthcare amenities was reduced, resulting in increased morbidity and mortality in patients at risk. Furthermore, as lockdown measures were largely adopted worldwide, the sedentary lifestyle and the increased consumption of processed nutrients or unhealthy food increased, and in the consequence, we might observe even 70% of overweight and obese population. Altogether, with the relatively low ratio of vaccinated people in many countries, and important health debt appeared, which is now and will be for next decade a large healthcare challenge. However, the experience gained in the COVID-19 pandemic and the new methods of patients' approaching have helped the medical system to overcome this crisis and will hopefully help in the case of new possible epidemics.

Factors associated with stroke after COVID-19 vaccination: a statewide analysis

Background

The objective of our study was to evaluate vaccine type, COVID-19 infection, and their association with stroke soon after COVID-19 vaccination.

Methods

In a retrospective cohort study, we estimated the 21-day post-vaccination incidence of stroke among the recipients of the first dose of a COVID-19 vaccine. We linked the Georgia Immunization Registry with the Georgia Coverdell Acute Stroke Registry and the Georgia State Electronic Notifiable Disease Surveillance System data to assess the relative risk of stroke by the vaccine type.

Results

Approximately 5 million adult Georgians received at least one COVID-19 vaccine between 1 December 2020 and 28 February 2022: 54% received BNT162b2, 41% received mRNA-1273, and 5% received Ad26.COV2.S. Those with concurrent COVID-19 infection within 21 days post-vaccination had an increased risk of ischemic (OR = 8.00, 95% CI: 4.18, 15.31) and hemorrhagic stroke (OR = 5.23, 95% CI: 1.11, 24.64) with no evidence for interaction between the vaccine type and concurrent COVID-19 infection. The 21-day post-vaccination incidence of ischemic stroke was 8.14, 11.14, and 10.48 per 100,000 for BNT162b2, mRNA-1273, and Ad26.COV2.S recipients, respectively. After adjusting for age, race, gender, and COVID-19 infection status, there was a 57% higher risk (OR = 1.57, 95% CI: 1.02, 2.42) for ischemic stroke within 21 days of vaccination associated with the Ad26.COV2.S vaccine compared to BNT162b2; there was no difference in stroke risk between mRNA-1273 and BNT162b2.

Conclusion

Concurrent COVID-19 infection had the strongest association with early ischemic and hemorrhagic stroke after the first dose of COVID-19 vaccination. Although not all determinants of stroke, particularly comorbidities, were considered in this analysis, the Ad26.COV2.S vaccine was associated with a higher risk of early post-vaccination ischemic stroke than BNT162b2.

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.

Benefits and Harms of COVID-19 Vaccines in Cardiovascular Disease: A Comprehensive Review

Patients with a history of cardiovascular disease (CVD) who contract coronavirus disease 2019 (COVID-19) tend to have a worse prognosis and more severe cardiovascular side effects. COVID-19 vaccines, which are intended to prevent COVID-19, may also potentially reduce the severity and complications (including cardiovascular sequelae) of COVID-19, especially in patients with a history of CVD. However, there have also been reports of cardiovascular side effects from COVID-19 vaccines of various brands and types. The purpose of this study is to review the benefits and harms of COVID-19 vaccines in relation to CVD. In this thorough review of the most current evidence on the benefits and harms of COVID-19 vaccines, we present information about the characteristics of cardiovascular complications. Most of the evidence focuses on myocarditis or pericarditis, which are most strongly associated with mRNA vaccines and predominantly occur in young males within days of receiving the second dose. Meanwhile, post-vaccination myocardial infarction is more common in older males, and the first dose of adenoviral vector vaccines appears to play a greater role in this complication. This information may guide us in formulating alternative options and implementing targeted surveillance. Gaining more knowledge about the potential benefits and harms of COVID-19 vaccines will improve our ability to make informed decisions and judgments about the balance of these factors.

Adverse Hematological Effects of COVID-19 Vaccination and Pathomechanisms of Low Acquired Immunity in Patients with Hematological Malignancies

The SARS-CoV-2 virus and the COVID-19 pandemic have spread across the world and severely impacted patients living with hematological conditions. Immunocompromised patients experience rapidly progressing symptoms following COVID-19 infection and are at high risk of death. In efforts to protect the vulnerable population, vaccination efforts have increased exponentially in the past 2 years. Although COVID-19 vaccination is safe and effective, mild to moderate side effects such as headache, fatigue, and soreness at the injection site have been reported. In addition, there are reports of rare side effects, including anaphylaxis, thrombosis with thrombocytopenia syndrome, Guillain-Barré Syndrome, myocarditis, and pericarditis after vaccination. Further, hematological abnormalities and a very low and transient response in patients with hematological conditions after vaccination raise concerns. The objective of this review is to first briefly discuss the hematological adverse effects associated with COVID-19 infection in general populations followed by critically analyzing the side effects and pathomechanisms of COVID-19 vaccination in immunocompromised patients with hematological and solid malignancies. We reviewed the published literature, with a focus on hematological abnormalities associated with COVID-19 infection followed by the hematological side effects of COVID-19 vaccination, and the mechanisms by which complications can occur. We extend this discussion to include the viability of vaccination efforts within immune-compromised patients. The primary aim is to provide clinicians with critical hematologic information on COVID-19 vaccination so that they can make informed decisions on how to protect their at-risk patients. The secondary goal is to clarify the adverse hematological effects associated with infection and vaccination within the general population to support continued vaccination within this group. There is a clear need to protect patients with hematological conditions from infection and modulate vaccine programs and procedures for these patients.

COVID-19 mRNA Vaccine Effectiveness against Elderly Frail People

The frail, elderly population is often characterized by poor immunogenicity post COVID-19 mRNA vaccination. "Inflame-ageing" and "immune-senescence" are pathogenetic mechanisms that might explain this phenomenon. Complex interplay with cytokines and microbiota is also implicated in this inflammatory cascade. The abovementioned population, although very important from immunologic perspective, has barely been included in the mRNA vaccination clinical trials.

Thrombotic events with or without thrombocytopenia in recipients of adenovirus-based COVID-19 vaccines

COVID-19, the severe acute respiratory syndrome, is one of the major emergencies that have affected health care systems. Drugs and oxygen are only partially effective in saving lives in patients with severe COVID-19, and the most important protection from death is vaccination. The widespread use of COVID-19 adenovirus-based vaccines has provided evidence for the occurrence of rare venous thrombotic events including cerebral venous thrombosis and splanchnic venous thrombosis in recipients of Vaxzevria and Jcovden vaccines and the review focus on them. One year ago, thromboses in Vaxzevria recipients have been associated with thrombocytopenia in the presence of antibodies to platelet factor 4 and have been called vaccine-induced immune thrombotic thrombocytopenia (VITT). The incidence of VITT is equal to 9-31 events per one million doses of vaccines as evaluated by health agencies worldwide and is higher in female and young vaccine recipients. More recently, by using the European EudraVigilance database, it has been demonstrated that the incidence of thrombosis in recipients of adenovirus-based vaccines is 5–10 fold higher than that of VITT and 7–12 fold higher than observed in the recipients of Comirnaty, an mRNA-based vaccine, suggesting that adenovirus-based vaccines cause not only VITT but also thrombosis without thrombocytopenia (non-VITT thrombosis). The incidence of the vaccine-dependent non-VITT thrombosis is different in the adenovirus-based vaccines and the VITT/non-VITT incidence ratio depends on the severity of thrombosis and is inversely related to the age of the recipients. The possible causes and clinical implications of non-VITT thrombosis in vaccine recipients are discussed.