Vaccine Adverse Effects Research Articles

Investigating Osteomyelitis as a Rare Adverse Effect of Vaccination in the Pediatric Population

Investigating Osteomyelitis as a Rare Adverse Effect of Vaccination in the Pediatric Population

Women Suffered More Than Men Both During and After the COVID-19 Pandemic-A Cross-Sectional Study Among 29,079 Patients With Type 2 Diabetes.

To investigate the gender differences and the disparities between infected and noninfected patients with type 2 diabetes (T2D) regarding patient-reported experiences during the COVID-19 pandemic in Norway. Register study using questionnaires sent electronically to patients with T2D, June 2022. The questionnaire included 82 questions covering COVID-19 disease, symptoms, medications, comorbidities, hospital care, possibility of working from home and information received from health authorities. Clinical and demographic data were collected from the Norwegian diabetes registry for adults. A total of 29,079 T2D patients participated, of whom 38.1% were women. Patients infected with COVID-19 were younger, had shorter diabetes duration and less comorbidities than noninfected (p < 0.01). Women reported significantly more anxiety, depression and fear of not getting their diabetes medication than men did. Most patients were vaccinated against COVID-19 (98.3%), whereas approximately 60% had received seasonal flu vaccine, and only 27.2% the pneumococcal vaccine. Women described more vaccine adverse effects and long Covid symptoms. Overall, 14% experienced vaccine complications and 27.3% of infected individuals reported long Covid symptoms. 2.4% of the infected patients needed hospital admission. Patients were satisfied with the follow-up of their diabetes, and with information from the government during the pandemic. Female patients were more likely to experience a prolonged Covid course, and higher degree of adverse effects from the COVID-19 vaccine than male patients. Also, long Covid symptoms were significantly more often reported among female patients, while men were more prone to be hospitalised when infected. Hospitalised patients, both men and women, had significantly higher HbA1C than those who were not hospitalised. T2D patients had a surprisingly low pneumococcal vaccination coverage, despite recommendations in national guidelines.

Post Covid-19 Vaccination Immune Response in Hemodialysis Patient Compared to Normal Population

Abstract Background The COVID-19 pandemic has profound adverse effects on the population on dialysis. Patients requiring dialysis are at an increased risk of SARS-CoV-2 infection and mortality, and many have experienced psychological distress as well as delayed or suboptimal care. COVID-19 survivors have prolonged viral shedding, but generally develop a robust and long-lasting humoral immune response that correlates with initial disease severity. However, protection against reinfection is incomplete. Aim of the Work This study aimed to studying the immune response to COVID-19 Viruse vaccination in hemodialysis patients compared to the normal population Patients and Methods This study is a prospective case control study which include 40 prevalent HD patients received COVID-19 vaccination in haemodialysis units, Ain Shams University Hospitals. In comparison to 20 healthy control individuals who also received COVID-19 vaccination. Results Our study showed that there was no statistically significant difference between the studied groups as regard demographic data. Where the age ranges from 24-60 years old. There was 11 female and 29 males in our participant. Regarding occupation, there were 11 participants not working and 29 were working. In our study, there was a significant negative correlation between, SARS COVID IgG Au/ml &amp; age per year, duration of hemodialysis per year, and parathyroid hormone. Whereas, there is a significant positive correlation between SARS COVID IgG Au/ml and kt/v % of renal hemodialysis dialysis patients. Otherwise, there is no significant relation between, SARS COVID IgG. In our study, there is a lower significant value of SARS COVID igG in renal dialysis patients compared to the control group regarding the history of COVID19 infection before vaccination and occurrence of post- vaccine adverse effects. Conclusion Hemodialysis patients demonstrate a hyporesponsiveness to vaccination against COVID-19. Although most patients on maintenance hemodialysis developed a substantial humoral response following the COVID vaccine, it was significantly lower than controls.

Analysis of COVID-19 vaccine type and adverse effects following complete vaccination

Analysis of COVID-19 vaccine type and adverse effects following complete vaccination

Impact of COVID-19 vaccination on seminal and systemic inflammation in men

Expedited development of SARS-CoV-2 vaccines led to public concerns regarding impacts of the novel vaccine on gametes in patients seeking assisted reproduction. In cases of an acute intermittent illness or fever in men, it is often advised to postpone ART treatments so that efforts can be made to enhance wellbeing and improve sperm parameters. However, it is unknown whether sperm parameters are altered in the acute (24–72 hour) phase following COVID-19 vaccination. We performed a longitudinal cohort study of 17 normospermic male patients attending a fertility clinic for semen analysis. Semen and matched peripheral blood samples were collected prior to vaccination, within 46 + 18.9 hours of vaccine course completion (acute) and at 88.4 + 12 days (3 months) post-vaccination. No overall change from baseline was seen in symptoms, mean volume, pH, sperm concentration, motility, morphology or DNA damage in the acute or long phase. Seminal plasma was found to be negative for anti-SARS-CoV2 Spike antibody detection, and MCP-1 levels showed an acute but transient elevation post-vaccine, while IL-8 was marginally increased 3 months after completion of vaccination. A modest, positive correlation was noted between serum levels of the anti-inflammatory cytokine IL-10 and self-reported symptoms post-vaccine. Our findings are reassuring in that no significant adverse effect of vaccination was noted and provide evidence to support the current recommendations of reproductive medicine organisations regarding timing of vaccination during fertility treatment.

Adverse effects of COVID-19 vaccines in the Moroccan adults and children during the pandemic

ObjectivesDuring the pandemic of covid-19, Safe and effective vaccines have been urgently needed. Our study aims to investigate the adverse effects of vaccines and their severity factors in people who have been vaccinated in the Rabat region. MethodsThis is a multicentric cross-sectional study conducted in the Rabat region of Morocco from February to December 2021. Consenting subjects aged 12 years and older who presented symptoms after a first, second or third dose of covid 19 vaccine and who received one of the following vaccines were included in the study: AstraZeneca-Oxford, Sinopharm, Pfizer-BioNTech. An evaluation form was drawn up. Univariate analysis was performed using the chi-square, Fisher's exact and Mann Whitney tests. Multivariate analysis was performed using logistic regression, and data analysis was performed using Jamovi 2.3.19 and R 4.3.1. ResultsWe recruited 489 patients with a median age of 52 years [32.3–66.0], 67.2 % were women,52.6%were vaccinated by AstraZeneca,4.8 % by Pfizer, and 42.6 % by Sinopharm, 84 of cases were severe 17.2 %, the majority of side effects were represented by influenza-like illness, fever, dizziness, vagal shock, skin rash, Covid, cardiac, digestive and neurological manifestations.In univariate analysis, age and the presence of a previous history were risk factors, and in multivariate analysis only age remained a risk factor for the severity of adverse events. ConclusionThe study identifies common adverse events and underlines the importance of ongoing surveillance and suggests the need for large samples in order to comprehensively assess the effects of vaccines.

Vaccine Adverse Effects Following Covishield among Health-care Workers in Central India

Abstract Introduction: This study aims to analyze common adverse effects following immunization that are temporally associated after receiving the above 2 doses of ChAdOx1 nCoV-19 Vaccine (Covishield) COVID-19 vaccines among health-care worker from January 2021 to April 2021, in the central region of India in a tertiary care hospital. Materials and Methods: A surveillance-based study was conducted between January 2021 and April 2021 among the health-care worker of the tertiary care hospital in the central part of India. The study was designed to identify the adverse effects reported after receiving a ChAdOx1 nCoV-19 Vaccine (Covishield) COVID-19 vaccination and demographic details were collected. Results: Within 48 h of the initial immunization dose, 651 mild adverse effects in all participants were documented. Headache (n = 168, 16%), fever (n = 105, 10%), fatigue (n = 115, 11%), and muscular discomfort (n = 115, 10%) were among the frequent side effects. One hundred and five minor adverse effects were reported between 3 and 7 days. No major adverse effects were observed after the first and second doses of vaccine. Conclusion: The first 48 h were the most common observational period for the short-term adverse effects of both dosages. After 15 days of both doses, the incidence declined for consecutive weeks until it was completely absent. The symptoms were transient and of a minor in nature. There were no documented severe vaccine-related side effects. Our research demonstrated that the vaccination had a decreased adverse event profile, was safe, and was well-tolerated.

An overview and single-arm meta-analysis of immune-mediated adverse events following COVID-19 vaccination.

We conducted an overview to assess immune adverse effects associated with the COVID-19 vaccine, guiding safer choices and providing evidence-based information to clinicians. Forty-three studies on adverse effects of vaccines were reviewed from PubMed, Embase, and Web of Science. Single-arm meta-analyses estimated summary effects, incidence, presentation, etc. An overview using single-arm meta-analysis and reported the findings following the guidelines outlined in the 'Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) specifically focusing on myocarditis and thrombosis. After screening 2,591 articles, 42 studies met the inclusion criteria. Methodological quality was evaluated using AMSTAR 2. Disagreements were resolved via consensus. Data analysis utilized a random-effects model in R software to estimate incidence rates of selected adverse events. After removing 1,198 duplicates and screening out irrelevant articles from a total of 2,591, we included 42 studies. Adverse reactions to vaccinations include myocarditis, thrombosis, skin reactions, GBS, etc. thrombosis and myocarditis are the most dangerous diseases associated with vaccination. Myocarditis occurred in 6% of Vector vaccine recipients, compared to 61% of mRNA vaccine recipients. Thrombosis was more common after Vector vaccination (91%) than after mRNA vaccination (9%). Furthermore, eight studies conducted anti-PF4 antibody tests and yielded a positivity rate of 67%. Meta-analysis showed that among all patients with Vaccine-induced Thrombotic Thrombocytopenia, cerebral venous sinus thrombosis occurred in 66%, and intracranial hemorrhage occurred in 43%. The rates of deep vein thrombosis and pulmonary thromboembolism in vaccinated patients were 13% and 23%, respectively, with a pooled case fatality rate of 30%. The results of this overview indicate the majority of adverse reactions are self-limiting and require minimal intervention, while rare occurrences such as myocarditis and thrombosis pose a potentially fatal threat.

Strategic Individual Behaviors and the Efficient Vaccination Subsidy

Abstract This study addresses the issue of how to set a consumer price of a vaccination against an infectious disease. We especially focus on the effects of strategic behaviors of individuals within a social group. In characterizing an equilibrium level of vaccination rate, the spill-over effect of vaccination is important not only in the light of group efficiency but also from each individual’s viewpoint. By constructing a simple game-theoretic model under the Nash conjecture where individuals rationally predict the resulting vaccination rate based on their own information, we analyze how the efficient vaccination subsidy is related to epidemiological as well as economic variables. In particular, we show that individuals over-react to the changes in their expectations over the virulency of a disease and also over the scale of adverse effects of vaccinations. We also discuss the necessary adjustment of a vaccination price when the public have misperception over certain epidemiological parameters.

Childhood vaccination hesitancy in Saudi Arabia: are we still facing a problem? A narrative review.

Vaccination is a crucial public health intervention for infection prevention. Yet, vaccine hesitation has emerged as a pressing public health concern. The objective of this review is to identify the widespread and causes of vaccine hesitancy prevalance among parents of children in Saudi Arabia. A narrative review, surveying several databases, including PubMed, PubMed Central, Scopus, Google Scholar, and relevant regional journals. We selected studies related to vaccine hesitancy prevalence and causes after removing duplicates and screening for relevance and access to full text. A total of 18 articles met the final selection criteria.The prevalence of parental vaccination reluctance in Saudi Arabia shown significant variability; ranging from 3.1-72.2%. Concerns regarding vaccine side effects appeared as the foremost reason for vaccine hesitancy. The review concluded that numerous Saudi Arabian parents still hesitate to vaccinate their children. They believe the potential adverse effects of vaccination outweigh the protective benefits against diseases.

Descriptive cross-sectional study to evaluate perception, attitude, and practice of parents regarding COVID-19 vaccination in children 10-12 years of age-A step toward prevention of future COVID-19 outbreaks in India.

COVID-19 was declared a global pandemic and all age groups were equally affected. Coronavirus had devastating effects worldwide due to the emergence of new variants till vaccination was adopted to eradicate the transmission of the virus and restore normalcy. However, children were not included in the initial phase of vaccination. The purpose of the study was to assess the level of perception, attitude, and practice among parents toward the COVID-19 vaccination drive in children 10-12 years of age. The present research is a cross-sectional questionnaire-based survey including parents of children aged 10-12 years as participants. The survey was conducted between May 2022 and July 2022 with a sample size of 320. A high willingness (80%) among parents was found for getting their children vaccinated. COVID-19 vaccines were perceived to be safe by the parents (59%) and efficacious (75%) for their children. Parents (67%) felt that the benefits of getting their children vaccinated against COVID-19 prevail over the risks of the vaccine. Parents 214 (67%) feel the need of getting their child vaccinated for sending them to school followed by availing of daycare facilities after school 54 (17%) among working parents. A significant association (P < 0.05) was seen between the variables of practice being followed by parents and their children as per COVID-19 norms. Parent's negative attitude toward COVID-19 vaccination was associated with availability of no/unclear safety information (36%), fear of adverse effects of vaccine (3%), and false belief of having long-term immunity due to natural infection (32%). The positive attitude of parents was due to trust in positive information/news about the vaccine (42%), belief in the safety and efficacy of the vaccine (5%), acceptability for mild adverse effects (1%), and the necessity of vaccine to send children to schools (1%). The awareness of parents regarding COVID-19 vaccination for children was limited, high level of acceptance for vaccination was seen in our study. We recommend to continuing educational programs through mass campaigns to increase increasing awareness among parents for getting COVID-19 vaccination for their children. Vaccine hesitancy including vaccine safety concerns of parents should be addressed by presenting myths and facts related to COVID-19 vaccine using television, radio, and social media platforms.

COVID-19 Vaccine Hesitancy and Associated Oral Cholera Vaccine Hesitancy in a Cholera-Endemic Country: A Community-Based Cross-Sectional Study in the Democratic Republic of Congo.

COVID-19 vaccine hesitancy and its enablers shape community uptake of non-covid vaccines such as the oral cholera vaccine (OCV) in the post-COVID-19 era. This study assessed the impact of COVID-19 vaccine hesitancy and its drivers on OCV hesitancy in a cholera-endemic region of the Democratic Republic of Congo. We conducted a community-based survey in Bukavu. The survey included demographics, intention to take OCV and COVID-19 vaccines, reasons for COVID-19 hesitancy, and thoughts and feelings about COVID-19 vaccines. Poisson regression analyses were performed. Of the 1708 respondents, 84.66% and 77.57% were hesitant to OCV alone and to both OCV and COVID-19, respectively. Hesitancy to COVID-19 vaccines rose OCV hesitancy by 12% (crude prevalence ratio, [cPR] = 1.12, 95%CI [1.03-1.21]). Independent predictors of OCV hesitancy were living in a semi-urban area (adjusted prevalence ratio [aPR] = 1.10, 95%CI [1.03-1.12]), religious refusal of vaccines (aPR = 1.06, 95%CI [1.02-1.12]), concerns about vaccine safety (aPR = 1.05, 95%CI [1.01-1.11]) and adverse effects (aPR = 1.06, 95%CI [1.01-1.12]), as well as poor vaccine literacy (aPR = 1.07, 95%CI [1.01-1.14]). Interestingly, the belief in COVID-19 vaccine effectiveness reduced OCV hesitancy by 24% (aPR = 0.76, 95%CI [0.62-0.93]). COVID-19 vaccine hesitancy and its drivers exhibited a significant domino effect on OCV uptake. Addressing vaccine hesitancy through community-based health literacy and trust-building interventions would likely improve the introduction of novel non-COVID-19 vaccines in the post-COVID-19 era.

Vaccination against the SARS-CoV-2 virus in patients undergoing Hymenoptera venom immunotherapy.

The SARS-CoV-2 epidemic has unquestionably left a significant mark on the global healthcare system. Implementation of the commonly available vaccinations against COVID-19 is intended to reduce the risk of a severe course of the disease. Due to a very brief development period of the new vaccines, concerns have appeared among the public with regard to the possible adverse effects of the newly-developed preparations, as well as to the risks of causing allergic reactions. Regular medical observation during the Hymenoptera venom immunotherapy provides significant possibilities to note any potential adverse effects of vaccines against COVID-19, as well as of complications of an experienced SARS CoV-2 infection. To assess the issues connected with vaccination against COVID-19, complications following vaccination, as well as incidence and course of the disease among patients undergoing venom immunotherapy (VIT) due to an allergy to Hymenoptera venom. We investigated 37 persons aged 19 to 70 (20 women; 17 men) undergoing Hymenoptera venom immunotherapy in our department. 21.6% have experienced an infection with the SARS-CoV-2 virus, confirmed by a diagnostic test. No person participating in the study had experienced a severe infection which would require hospitalization. Elderly people have been vaccinated statistically significantly more often than young people. The risk related to vaccination in this group of patients does not seem to be higher than in the general population.

Autoimmune rheumatic diseases and COVID-19 vaccination: a retrospective cross-sectional study from Astana.

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus has had an unprecedented impact on people around the world, particularly those who were suffering from autoimmune rheumatic diseases (AIRDs). The world community acknowledges the significance of COVID-19 vaccination in patients with autoimmune disorders and emphasizes the priority of this category to receive vaccination over the general population. Although many studies have been published since the first phases of vaccination all over the world, multiple related factors still need to be further investigated. We investigated the COVID-19 vaccination status in patients with AIRDs, by performing a cross-sectional, interview-based study filled in by patients attending their clinics in the Astana city, capital of Kazakhstan, from April to July 2023. The survey questionnaire consisted of a set of questions, concerning patient characteristics, treatment details, accepted vaccines and characteristics of COVID-19 infection. The study objectives were to evaluate vaccine hesitancy, adverse effects, breakthrough infections and flare of underlying rheumatic disease in this population subgroup. There were 193 participants, with a median age of 50.3 ±12.9 years. Among them, 62 (32.1%) were vaccinated with at least single dose of vaccine, 16 (25.8%) of whom were fully vaccinated. The commonest (89; 68%) reason for vaccine hesitancy was a fear of autoimmune disease worsening. Vaccine-related adverse effects (AEs) were reported by 66.7% of patients. We found that vaccination provoked AIRD exacerbation in 19% of patients with AEs. Eight patients reported flare of pre-existing rheumatic disease after vaccination. The incidence of breakthrough infections was similar in the groups of vaccinated individuals (n = 12), 12.9% of whom were partially and 6.5% fully vaccinated. The vaccination was found to be safe in patients with rheumatic diseases. Fear of autoimmune status was the major reason for vaccine reluctance. All reported adverse events were minor. The minority subgroup within the sample had subsequent breakthrough infections or autoimmune disease flare-ups.

Observed Adverse Effects of Sinopharm COVID-19 Vaccine in Healthcare Workers

Abstract: Background: Covid-19 was first identified in Wuhan China in December 2019, and rapidly spread world over. Vaccine was always thought as first line defence against viral infections, and Covid was no exception. Although developed through different technologies, Pakistan got its share of Sinopharm from China and vaccination started in February 2021, with priority for Healthcare workers. There were lot of myths and hesitancy related with the adverse effects and urgency in approving these vaccines. Addressing adverse effects in post vaccinated population hence, became an important matter. Objective: Aim of this study was to observe the adverse effects of this vaccine in Pakistani population, to assess safety and develop confidence in Healthcare Workers. Materials and Methods: A cross-sectional Observation study was carried out in vaccinated Healthcare Professional through Non-probability purposive sampling over a period of one month. A team collected data directly, as well as on the telephone call. A Google form was also generated and sent. Information was collected and analysed on IBM-SPSS 23.0 Result: Majority of the participants were less than 55 years with female dominance. Among co-morbidities, hypertension was most common, followed by diabetes. In local and systemic adverse effects, pain and fatigue were most common, followed by muscle weakness, fever and headache respectively. These effects were also more common after first injection. Conclusion: Results favor that people should be more careful after the first dose as more adverse effects were felt after that. This vaccine has a good safety profile as no major adverse effects were noticed. It was also considered safe for patients with co-morbidities.

Surveillance of COVID-19 vaccines: A comprehensive analysis of the first immunization drive in Ecuador

The initial phase of the COVID-19 vaccination in Ecuador occurred between April and November 2021. Initially, it focused on priority populations, including health professionals and other front-line workers. During this period, there was limited knowledge about the vaccine's adverse effects. A non-probability, observational study was conducted among university staff in Guayaquil, Ecuador, who received the AstraZeneca vaccine (n = 423) between April and November 2021. This study aimed to compare the acute adverse reactions by doses and to report the incidence of long-term adverse reactions within the AstraZeneca group. As a result, comparing acute adverse reactions between doses, the odds ratio for local pain, headache, muscle pain, fever, and chills are statistically higher after the first dose than the second dose. Survival curves indicated these symptoms appeared mainly within the first 6 h post-vaccination. This is the first pharmacovigilance study from Ecuador that analyzes survival probabilities for the AstraZeneca vaccine's adverse effects.

Short-term COVID-19 vaccine adverse effects among adults in Ekiti State, Nigeria

Background The safety of the COVID-19 vaccines has been a topic of concern globally. This issue of safety is associated with vaccine hesitancy due to concerns about the adverse effects of the vaccines. Consequently, this study determined the short-term safety profile of the Oxford/AstraZeneca COVID-19 vaccine in Ekiti State, Nigeria. Methods Descriptive cross-sectional study conducted between May and July 2021 among individuals who had received the first dose of the first batch of the Oxford/AstraZeneca COVID-19 vaccine at Ekiti State University Teaching Hospital (EKSUTH), Ado-Ekiti, Nigeria. A Google form was used to collect data on the adverse effects of the vaccine. Results Out of over 1,000 individuals who were approached, 758 respondents completed the study. A large percentage (57.4%) of those who received the vaccines were healthcare workers. Adverse effects were reported in 70.8% of the participants with most manifesting on the first day of the vaccination. The predominant adverse effects were injection site soreness (28.5%), followed by fatigue (18.7%) and muscle pain (8.6%). There was no report of severe adverse effects such as anaphylactic reactions, thrombosis, myocarditis, transient myelitis, or Guillen-Barre syndrome. Conclusion This study found that self-reported adverse effects of the Oxford/AstraZeneca COVID-19 vaccine were mild and short in duration. This outcome has promising implications for improving COVID-19 vaccine uptake in the immediate environment and Nigeria.

The use of health education as a tool to combat the spread of fake news about vaccination

Vaccines can be understood as technological advances that aim to induce an immunological response through exposure to certain infectious agents, or specific particles thereof. The immunological response obtained creates memory and is capable of reducing the risk of developing diseases, as well as reducing mortality and complications in the event of an eventual infection. The general objective of this study aims to highlight how nurses' actions in the context of health education can help combat fake news related to vaccination. Fake news gained strength with the advent of social networks, and the spread of fake news increasingly threatens several achievements already achieved, including in the area of health. In this sense, there is an intimate relationship between the dissemination of fake news, the anti- vaccine movement and vaccine hesitancy. This is an investigation carried out through a review of scientific literature, which by definition has a qualitative- descriptive character. For its preparation, the findings of 21 works related to the proposed theme were selected, analyzed and summarized. The time frame covered the period from 2018 to 2023, that is, the last 6 years. Data were obtained through the following databases: Google Scholar, PubMed, VHL/Lilacs and Scopus. It was evident that the growing vaccine hesitancy may be associated with factors such as the population's distrust in relation to scientific information about immunization agents, related to the dissemination of fake news regarding the beneficial and adverse effects of vaccines. Above all, the strength of social networks in disseminating these untruths was demonstrated, and the need for public policy interventions and strategies to combat this misinformation.

Prevalence of covid-19 breakthrough after vaccination and adverse effects of vaccines

Objective: To assess the prevalence of breakthrough Covid 19 after vaccination and adverse effects of vaccines. Methodology: A descriptive cross-sectional study was conducted at three mega vaccination centers in Islamabad from December 1, 2021, to May 1, 2022. The sample size consisted of 300 participants (both males and females) in the age range of 30-60 years. To avoid ambiguities in answers, we included only those participants who were fully vaccinated. Among these, 150 were healthy individuals and 150 with co-morbidities, were selected through convenience sampling. Data were collected and analyzed using a pre-designed questionnaire and SPSS version 21. Results: A significant association between breakthrough COVID-19 and age and symptoms were found in fully vaccinated individuals with and without comorbidities. The type of vaccine had a significant association only in individuals without medical illness. No significant side effects of the vaccine or gender association were found in either group. We also found a significant association between breakthrough COVID-19 symptoms and the type of vaccine used. Conclusion: A significant association between vaccine type and breakthrough COVID was observed only in healthy individuals, probably because of their different mechanisms of action.

COVID-19 vaccination-related tinnitus is associated with pre-vaccination metabolic disorders.

Cases of tinnitus have been reported following administration of COVID-19 vaccines. The aim of this study was to characterize COVID-19 vaccination-related tinnitus to assess whether there is a causal relationship, and to examine potential risk factors for COVID-19 vaccination-related tinnitus. We analyzed a survey on 398 cases of COVID-19 vaccination-related tinnitus, and 699,839 COVID-19 vaccine-related reports in the Vaccine Adverse Effect Reporting System (VAERS) database that was retrieved on 4 December 2021. We found that following COVID-19 vaccination, 1) tinnitus report frequencies for Pfizer, Moderna and Janssen vaccines in VAERS are 47, 51 and 70 cases per million full vaccination; 2) the symptom onset was often rapid; 3) more women than men reported tinnitus and the sex difference increased with age; 4) for 2-dose vaccines, the frequency of tinnitus was higher following the first dose than the second dose; 5) for 2-dose vaccines, the chance of worsening tinnitus symptoms after second dose was approximately 50%; 6) tinnitus was correlated with other neurological and psychiatric symptoms; 7) pre-existing metabolic syndromes were correlated with the severity of the reported tinnitus. These findings suggest that COVID-19 vaccination increases the risk of tinnitus, and metabolic disorders is a risk factor for COVID-19 vaccination-related tinnitus.