BACKGROUND: The COVID-19 pandemic, caused by SARS-CoV-2, has had a profound impact worldwide, leading to widespread morbidity and mortality. Vaccination against COVID-19 is a critical tool in controlling the spread of the virus and reducing the severity of the disease. However, the rapid development and deployment of COVID-19 vaccines have raised concerns about potential adverse events following immunization (AEFIs). Understanding the temporal and spatial patterns of these AEFIs is crucial for an effective public health response and vaccine safety monitoring.
OBJECTIVE: This study aimed to analyze the temporal and spatial characteristics of AEFIs associated with COVID-19 vaccines in the United States reported to the Vaccine Adverse Event Reporting System (VAERS), thereby providing insights into the patterns and distributions of the AEFIs, the safety profile of COVID-19 vaccines, and potential risk factors associated with the AEFIs.
METHODS: We conducted a retrospective analysis of administration data from the Centers for Disease Control and Prevention (n=663,822,575) and reports from the surveillance system VAERS (n=900,522) between 2020 and 2022. To gain a broader understanding of postvaccination AEFIs reported, we categorized them into system organ classes (SOCs) according to the Medical Dictionary for Regulatory Activities. Additionally, we performed temporal analysis to examine the trends of AEFIs in all VAERS reports, those related to Pfizer-BioNTech and Moderna, and the top 10 AEFI trends in serious reports. We also compared the similarity of symptoms across various regions within the United States.
RESULTS: Our findings revealed that the most frequently reported symptoms following COVID-19 vaccination were headache (n=141,186, 15.68%), pyrexia (n=122,120, 13.56%), and fatigue (n=121,910, 13.54%). The most common symptom combination was chills and pyrexia (n=56,954, 6.32%). Initially, general disorders and administration site conditions (SOC 22) were the most prevalent class reported. Moderna exhibited a higher reporting rate of AEFIs compared to Pfizer-BioNTech. Over time, we observed a decreasing reporting rate of AEFIs associated with COVID-19 vaccines. In addition, the overall rates of AEFIs between the Pfizer-BioNTech and Moderna vaccines were comparable. In terms of spatial analysis, the middle and north regions of the United States displayed a higher reporting rate of AEFIs associated with COVID-19 vaccines, while the southeast and south-central regions showed notable similarity in symptoms reported.
CONCLUSIONS: This study provides valuable insights into the temporal and spatial patterns of AEFIs associated with COVID-19 vaccines in the United States. The findings underscore the critical need for increasing vaccination coverage, as well as ongoing surveillance and monitoring of AEFIs. Implementing targeted monitoring programs can facilitate the effective and efficient management of AEFIs, enhancing public confidence in future COVID-19 vaccine campaigns.

OBJECTIVE: Bivalent COVID-19 mRNA vaccines, which contain two different components, were authorized to provide protection against both the original strain of SARS-CoV-2 and the Omicron variant as a measure to address the COVID-19 pandemic. Concerns regarding the risk of myocarditis/pericarditis associated with bivalent vaccination have been raised due to the observed superior neutralizing antibody responses. This study aimed to investigate the risk of myocarditis/pericarditis following bivalent COVID-19 mRNA vaccination compared to monovalent vaccination.
METHODS: The CDC COVID Data Tracker and the Vaccines Adverse Event Reporting System (VAERS) were analyzed between December 13, 2020 to March 8, 2023. Reporting rates were determined by dividing the number of myocarditis/pericarditis cases by the total number of vaccine doses administered. Disproportionality patterns regarding myocarditis/pericarditis were evaluated for various COVID-19 mRNA vaccinations using reporting odds ratios (RORs).
RESULTS: The reporting rate for myocarditis/pericarditis following original monovalent COVID-19 mRNA vaccination was 6.91 (95 % confidence interval [95 %CI] 6.71-7.12) per million doses, while the reporting rate for bivalent vaccination was significantly lower (1.24, 95%CI 0.96-1.58). Disproportionality analysis revealed a higher reporting of myocarditis/pericarditis following original vaccination with a ROR of 2.21 (95 %CI 2.00-2.43), while bivalent COVID-19 mRNA vaccination was associated with fewer reports of myocarditis/pericarditis (ROR 0.57, 95 %CI 0.45-0.72). Sub-analyses based on symptoms, sex, age and manufacturer further supported these findings.
CONCLUSIONS: This population-based study provides evidence that bivalent COVID-19 mRNA vaccination is not associated with risk of myocarditis/pericarditis. These findings provide important insights into the safety profile of bivalent COVID-19 mRNA vaccines and support their continued use as updated boosters.

We aimed to analyze the characteristics of serious adverse events following immunizations (AEFIs) to identify potential safety information and prediction features. We screened the individual case safety reports (ICSRs) in adults who received mRNA-based COVID-19 vaccines using the Vaccine Adverse Event Reporting System until December 2021. We identified the demographic and clinical characteristics of ICSRs and performed signal detection. We developed prediction models for serious AEFIs and identified the prognostic features using logistic regression. Serious ICSRs and serious AEFIs were 51,498 and 271,444, respectively. Hypertension was the most common comorbidity (22%). Signal detection indicated that the reporting odds ratio of acute myocardial infarction (AMI) was more than 10 times. Those who had experienced myocardial infarction (MI) were 5.7 times more likely to suffer from MI as an AEFI (95% CI 5.28-6.71). Moreover, patients who had atrial fibrillation (AF), acute kidney injury (AKI), cardiovascular accident (CVA), or pulmonary embolism (PE) were 7.02 times, 39.09 times, 6.03 times, or 3.97 times more likely to suffer from each AEFI, respectively. Our study suggests that vaccine recipients who had experienced MI, AF, AKI, CVA, or PE could require further evaluation and careful monitoring to prevent those serious AEFIs.

Postmarket drug safety database like vaccine adverse event reporting system (VAERS) collect thousands of spontaneous reports annually, with each report recording occurrences of any adverse events (AEs) and use of vaccines. We hope to identify signal vaccine-AE pairs, for which certain vaccines are statistically associated with certain adverse events (AE), using such data. Thus, the outcomes of interest are multiple AEs, which are binary outcomes and could be correlated because they might share certain latent factors; and the primary covariates are vaccines. Appropriately accounting for the complex correlation among AEs could improve the sensitivity and specificity of identifying signal vaccine-AE pairs. We propose a two-step approach in which we first estimate the shared latent factors among AEs using a working multivariate logistic regression model, and then use univariate logistic regression model to examine the vaccine-AE associations after controlling for the latent factors. Our simulation studies show that this approach outperforms current approaches in terms of sensitivity and specificity. We apply our approach in analyzing VAERS data and report our findings.

UNASSIGNED: Following the roll-out of the Pfizer-BioNTech BNT162b2, Moderna mRNA-1273, and Janssen Ad26.COV2.S coronavirus disease 2019 (COVID-19) injections in the United States, millions of individuals have reported adverse events (AEs) using the vaccine adverse events reports system (VAERS). The objective of this analysis is to describe the myocarditis data in VAERS and the COVID-19 vaccines as potential determinants of myocarditis.
UNASSIGNED: We used VAERS data to examine the frequency of reporting myocarditis since the beginning of the mass vaccination campaign and compared this with historical values in VAERS and COVID-19 vaccine administration data from the Our World in Data database. We examined myocarditis reports in VAERS in the context of sex, age, and dose. Statistical analysis was done using the Student\'s t-test to determine statistically significant differences between ages among myocarditis adverse events (AEs) and the chi-square test to determine relationships between categorical variables with statistical significance.
UNASSIGNED: We found the number of myocarditis reports in VAERS after COVID-19 vaccination in 2021 was 223 times higher than the average of all vaccines combined for the past 30 years. This represented a 2500% increase in the absolute number of reports in the first year of the campaign when comparing historical values prior to 2021. Demographic data revealed that myocarditis occurred most in youths (50%) and males (69%). A total of 76% of cases resulted in emergency care and hospitalization. Of the total myocarditis reports, 92 individuals died (3%). Myocarditis was more likely after dose 2 (p < 0.00001) and individuals less than 30 years of age were more likely than individuals older than 30 to acquire myocarditis (p < 0.00001).
UNASSIGNED: COVID-19 vaccination is strongly associated with a serious adverse safety signal of myocarditis, particularly in children and young adults resulting in hospitalization and death. Further investigation into the underlying mechanisms of COVID-19 vaccine-induced myocarditis is imperative to create effective mitigation strategies and ensure the safety of COVID-19 vaccination programs across populations.
Using VAERS to understand myocarditis associated with COVID-19 vaccination Why was the study done? Heart inflammation, known as myocarditis, has been previously associated with COVID-19 vaccination. After the Pfizer-BioNTech, Moderna, and Janssen COVID-19 vaccines were given in the United States, millions of people reported side effects, including myocarditis, using a system called the Vaccine Adverse Event Reporting System (VAERS). Therefore, the researchers sought to further investigate possible links between COVID-19 vaccination and myocarditis using VAERS. What did the researchers do? The researchers used VAERS to check the frequency of myocarditis reports after COVID-19 vaccination and compared this with past reports from other vaccines over the years. They also studied details such as the age and gender of those affected, and which dose of the vaccine they had received. What did the researchers find? In 2021, there was a dramatic increase in the number of myocarditis reports linked to the COVID-19 vaccine, far higher than the reports from all other vaccines combined over the previous 30 years. This side effect was mostly reported in young individuals, especially males. Most of those who reported myocarditis needed emergency medical care or had to be hospitalized. Out of those affected, 92 individuals died. Myocarditis was more likely following a second dose of vaccine. Furthermore, individuals under the age of 30 were more prone to acquire myocarditis from COVID-19 vaccination compared to those aged 30 and above. What do the findings mean? The researchers found a strong link between COVID-19 vaccination and myocarditis, especially in kids and young adults. This can lead to hospital stays and, in some cases, death. We need to study more about how the COVID-19 vaccine might cause heart inflammation to find ways to prevent it and make sure the vaccine is safe for continued use in all age groups.

Vaccine Adverse Events ReportingSystem (VAERS) is a promising resource of tracking adverse events following immunization. Medical Dictionary for Regulatory Activities (MedDRA) terminology used for coding adverse events in VAERS reports has several limitations. We focus on developing an automated system for semantic extraction of adverse events following vaccination and their temporal relationships for a better understanding of VAERS data and its integration into other applications. The aim of the present studyis to summarize the lessons learned during the initial phase of this project in annotating adverse events following influenza vaccination and related to Guillain-Barré syndrome (GBS). We emphasize on identifying the limitations of VAERS and MedDRA.
We collected 282 VAERS reports documented between 1990 and 2016 and shortlisted those with at least 1,100 characters in the report. We used a subset of 50 reports for the preliminary investigation and annotated all adverse events following influenza vaccination by mapping to representative MedDRA terms. Associated time expressions were annotated when available. We used 16 System Organ Class (SOC) level MedDRA terms to map GBS related adverse events and expanded some SOC terms to Lowest Level Terms (LLT) for granular representation. We annotated three broad categories of events such as problems, clinical investigations, and treatments/procedures. The inter-annotator agreement of events achieved was 86%. Incomplete reports, typographical errors, lack of clarity and coherence, repeated texts, unavailability of associated temporal information, difficulty to interpret due to incorrect grammar, use of generalized terms to describe adverse events / symptoms, uncommon abbreviations, difficulty annotating multiple events with a conjunction / common phrase, irrelevant historical events and coexisting events were some of the challenges encountered. Some of the limitations we noted are in agreement with previous reports.
We reported the challenges encountered and lessons learned during annotation of adverse events in VAERS reports following influenza vaccination and related to GBS. Though the challenges may be due to the inevitable limitations of public reporting systems and widely reported limitations of MedDRA, we emphasize the need to understand these limitations and extraction of other supportive information for a better understanding of adverse events following vaccination.

UNASSIGNED: There is a high level of public and professional interest related to potential safety issues of the COVID-19 vaccines; however, no serious adverse cardiovascular events were reported in phase 3 randomized controlled trials of their safety and efficacy. Moreover, none of the case series from the United States (US) of these potential complications have been population-based.
UNASSIGNED: To estimate the reporting rates of myocarditis and pericarditis in the US using the Vaccine Adverse Event Reporting System (VAERS), and to assess if these adverse events were disproportionally reported among the different COVID-19 vaccines.
UNASSIGNED: All cases of myocarditis and pericarditis from VAERS reported up to July 28, 2021.
UNASSIGNED: Single-dose Ad26.COV2.S, BNT162b2 mRNA, or mRNA-1273 SARS-CoV-2 vaccinations.
UNASSIGNED: Reporting rates were computed by dividing the total number of cases of myocarditis and pericarditis (combined) by the total number of vaccine doses administered. Disproportionality analyses were performed to evaluate disproportional reporting of myocarditis and pericarditis for the Ad26.COV2.S and mRNA-1273 vaccines vs. the BNT162b2 mRNA vaccine.
UNASSIGNED: By July 28, 2021, 1392, 699, and 68 cases of myocarditis or pericarditis had been reported out of 1.91, 1.38, and 1.33 million administered doses of the BNT162b2 mRNA, mRNA-1273, and Ad26.COV2.S COVID-19 vaccines, respectively. Median times to event were 3 days, 3 days, and 9 days for the BNT162b2 mRNA, mRNA-1273, and Ad26.COV2.S COVID-19 vaccines. The reporting rates for myocarditis or pericarditis were 0.00073 (95% confidence interval, 95% CI 0.00069-0.00077), 0.00051 (95% CI 0.00047-0.00055), and 0.00005 events per dose (95% CI 0.00004-0.00006) for the BNT162b2 mRNA, mRNA-1273, and Ad26.COV2.S COVID-19 vaccines, respectively. Myocarditis and pericarditis were disproportionally reported following the BNT162b2 mRNA vaccine when compared with the other vaccines, using both disproportionality measures.
UNASSIGNED: We found reporting rates of myocarditis and pericarditis to be less than 0.1% after COVID-19 vaccination. Rates were highest for the BNT162b2 mRNA vaccine, followed by the mRNA-1273 and Ad26.COV2.S, respectively. However, the reporting rates of myocarditis and pericarditis secondary to vaccination remains less common than those seen for SARS-CoV-2 infection.

The rapid development of COVID-19 vaccines has provided crucial tools for pandemic control, but the occurrence of vaccine-related adverse events (AEs) underscores the need for comprehensive monitoring.
This study analyzed the Vaccine Adverse Event Reporting System (VAERS) data from 2020-2022 using statistical methods such as zero-truncated Poisson regression and logistic regression to assess associations with age, gender groups, and vaccine manufacturers.
Logistic regression identified 26 System Organ Classes (SOCs) significantly associated with age and gender. Females displayed especially higher odds in SOC 19 (Pregnancy, puerperium and perinatal conditions), while males had higher odds in SOC 25 (Surgical and medical procedures). Older adults (>65) were more prone to symptoms like Cardiac disorders, whereas those aged 18-65 showed susceptibility to AEs like Skin and subcutaneous tissue disorders. Moderna and Pfizer vaccines induced fewer SOC symptoms compared to Janssen and Novavax. The zero-truncated Poisson regression model estimated an average of 4.243 symptoms per individual.
These findings offer vital insights into vaccine safety, guiding evidence-based vaccination strategies and monitoring programs for precise and effective outcomes.

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.
CONCLUSIONS: 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.

Covid immunization commenced on 2nd Feb 2021 in Pakistan and as of 7th Sep 2021, over 84 million vaccine doses were administered in Pakistan, of which 72% procured by the government, 22% received through Covax and 6% were donated. The vaccines rolled out nationally included: Sinopharm, Sinovac and CanSinoBIO (China), AstraZeneca (UK), Moderna and Pfizer (USA), Sputnik (Russia), and PakVac (China/Pakistan). About half of the eligible population in Pakistan (63 m) had received at least one dose of Covid vaccine as of Sep 2021. Pakistan National Pharmacovigilance Centre (PNPC) in coordination with WHO, MHRA and Uppsala Monitoring Centre (UMC) established pharmacovigilance centers across Pakistan. The Covid vaccine AEFIs in Pakistan were mainly reported via NIMS (National Immunization Management System), COVIM (Covid-19 Vaccine Inventory Management System), 1166 freephone helpline and MedSafety. There have been 39,291 ADRs reported as of 30th Sept 2021, where most reported after the first dose (n = 27,108) and within 24-72 h of immunization (n = 27,591). Fever or shivering accounted for most AEFI (35%) followed by injection-site pain or redness (28%), headache (26%), nausea/vomiting (4%), and diarrhoea (3%). 24 serious AEFIs were also reported and investigated in detail by the National AEFI review committee. The rate of AEFIs reports ranged from 0.27 to 0.79 per 1000 for various Covid vaccines in Pakistan that was significantly lower than the rates in UK (∼4 per 1000), primarily atrributed to underreporting of cases in Pakistan. Finally, Covid vaccines were well tolerated and no significant cause for concern was flagged up in Pakistan\'s Covid vaccine surveillance system concluding overall benefits outweighed risks.