Anxiety-related adverse events following immunization (AEFI): A systematic review of published clusters of illness

Immunization-related stress and stress-related responses of mucosal versus intramuscular COVID-19 vaccination among adults in China

BACKGROUND

In late 2022, China became the first country to roll out mucosal COVID-19 vaccines. No prior study has yet compared the immunization stress-related responses (ISRR) among different routes of COVID-19 vaccine delivery. We aimed to compare the immunization-related psychological stress and ISRR between mucosal and intramuscular COVID-19 vaccines.

METHODS

A cross-sectional questionnaire survey using a biopsychosocial framework design was performed from January 11 to 20, 2023. Adults with COVID-19 vaccination were eligible for the study, and a total of 1073 adults participated with community-based sample. Primary outcomes were the psychological stress levels and prevalence of ISRR. Multivariate regression models were employed to compare these outcomes between the two vaccination groups. The potential mediating effects of stress on vaccination and ISRR were examined using bootstrap sampling method. To further ensure the robustness of our results, sensitivity analysis with propensity score matching was performed.

FINDINGS

In the univariate analysis, participants who received mucosal vaccination reported significantly lower stress levels compared to those who received intramuscular vaccination (3.39 ± 3.02 vs. 3.93 ± 3.24, P = .006). The prevalence of overall ISRR was significantly lower in the mucosal group compared to the intramuscular group (38.4% vs. 47.9%, P = .002). Multivariate regression models revealed that participants who received mucosal vaccination had a significantly lower stress level (β = -0.516, 95% CI: -0.852 to -0.180; P = .003) and 38.7% fewer overall ISRR (OR = 0.613, 95% CI: 0.427 to 0.881; P = .008), particularly in terms of neurological symptoms. The immunization-related stress mediated the association between vaccination type and ISRR, with indirect effects estimated at 0.0663 (95% CI: 0.0195 to 0.1346) for overall ISRR.

CONCLUSIONS

Mucosal COVID-19 vaccination was associated with reduced psychological stress and physical responses, as compared to intramuscular vaccination, which may contribute to increased trust and compliance with routine or mass vaccination efforts in the future.

Safety profile of inactivated COVID-19 in healthy adults aged ≥ 18 years: A passive surveillance in Indonesia

Coronavirus Disease 2019 (COVID-19) vaccination in Indonesia has shown effectiveness in reducing the morbidity and mortality of Covid-19. The study aims to evaluate the incidence rate and severity of Adverse Events Following Immunization (AEFI) of inactivated SARS-CoV-2 vaccine during the first quarter of 2021 until the second quarter of 2022 in Indonesia. More than two hundred million Sinovac/CoronaVac were given from January 13th, 2021, until June 30th, 2022. Data for this study were collected manually and electronically from the national vaccine safety website managed by the National Committee (NC) of AEFI Indonesia and the Ministry of Health Indonesia. The total number of injections observed in the study was 264,311,992 doses consisting of 142,449,795 (first dose), 121,613,324 (second dose), and 248,873 (booster dose). Of the injections given, 301 subjects with Serious AEFIs (SAE) and 10.261 subjects with non-serious AEFIs (AE) reported, with a majority of SAE and AEs found in the first dose. Most of the SAEs were classified as coincidental events by the NC AEFI (IR 0.8/1 million doses on first dose injection; 0.31 on second dose injection). ISRR (immunization stress-related response) is in the second rank of SAEs reported (0.59 IR/1 million doses on the first dose; 0.14 on the second dose). The incidence rate of SAEs and AEs, both in the variable of age, sex, and symptoms per 1 million dose injections in Indonesia, was very rare according to WHO guidelines. Most SAEs were classified as coincidences or unrelated to the vaccine. The result showed that the Sinovac/CoronaVac in Indonesia is safe.

Role of Psychosomatic Symptoms in COVID-19 Vaccine Hesitancy

Vaccination against COVID-19 is one of the highly effective preventative strategies to reduce morbidity and mortality associated with COVID-19 infection. The rapid approval of COVID-19 vaccination due to the raging pandemic, media coverage, anti-vaccination groups, and concerns about adverse effects associated with vaccination has given rise to COVID-19 vaccine hesitancy. Current evidence suggests that psychosomatic and nocebo-related adverse effects account for a significant proportion of common adverse effects following COVID-19 vaccination. The most common adverse effects are headache, fatigue, and myalgia, which are highly prone to nocebo effects. In our review article, we discuss the role of psychosomatic and nocebo effects in COVID-19 vaccination-related hesitancy, predictors of such effects, and strategies to reduce vaccine hesitancy. General education regarding psychosomatic and nocebo effects and specialized education for at-risk populations may reduce psychosomatic and nocebo-related adverse effects following COVID-19 vaccination, ultimately reducing hesitancy.

The conundrum of COVID-19 mRNA vaccine-induced anaphylaxis

Novel messenger RNA (mRNA) vaccines have proven to be effective tools against coronavirus disease 2019, and they have changed the course of the pandemic. However, early reports of mRNA vaccine-induced anaphylaxis resulted in public alarm, contributing toward vaccine hesitancy. Although initial reports were concerning for an unusually high rate of anaphylaxis to the mRNA vaccines, the true incidence is likely comparable with other vaccines. These reactions occurred predominantly in young to middle-aged females, and many had a history of allergies. Although initially thought to be triggered by polyethylene glycol (PEG), lack of reproducibility of these reactions with subsequent dosing and absent PEG sensitization point away from an IgE-mediated PEG allergy in most. PEG skin testing has poor posttest probability and should be reserved for evaluating non-vaccine-related PEG allergy without influencing decisions for subsequent mRNA vaccination. Immunization stress-related response can closely mimic vaccine-induced anaphylaxis and warrants consideration as a potential etiology. Current evidence suggests that many individuals who developed anaphylaxis to the first dose of an mRNA vaccine can likely receive a subsequent dose after careful evaluation. The need to understand these reactions mechanistically remains critical because the mRNA platform is rapidly finding its way into other vaccinations and therapeutics.

Willingness to receive a vaccine is influenced by adverse events following immunisation experienced by others

An adverse event following immunization (AEFI) can have consequences for an individual's future decision making and may contribute to vaccine hesitancy. AEFIs vary in severity and can be experienced directly (by an individual themselves) or indirectly (through witnessed or recounted events). We sought to measure the prevalence of specific AEFIs and understand which AEFIs have the greatest associations with reduced willingness to receive a vaccine and how injection anxiety may moderate the relationship. We conducted a cross-sectional online survey with both qualitative and quantitative elements in a sample of adults aged 18 years and over in Australia. Nineteen percent of the 1050 respondents reported experiencing an AEFI that they found stressful. Those who experienced an AEFI reported significantly higher levels of injection anxiety than those who did not. Within the group who reported experiencing an AEFI, respondents were significantly less likely to be willing to receive a COVID-19 vaccine if they reported: indirect exposure to an uncommon/rare AEFI compared with other AEFIs (aOR:0.39; 95% CI: 0.18-0.87); indirect exposure to a scientifically unsupported AEFI compared with other AEFIs (aOR:0.18; 95% CI: 0.05-0.57). Direct exposure to an AEFI was not associated with willingness to receive a COVID-19 vaccine. For those who reported experiencing an AEFI, the odds of willingness to receive a COVID-19 vaccine decreased significantly with an increase in injection anxiety (aOR:0.94; 95% CI: 0.9-0.98). Our results suggest that more is needed to mitigate the consequences of AEFIs on vaccine willingness. Empathically acknowledging at a community level, the experience of both real and perceived AEFIs and incorporating accounts of positive vaccination experiences in vaccine hesitancy interventions may be useful.

Allergic adverse events following immunization: Data from post-marketing surveillance in Apulia region (South of Italy)

Introduction

Among adverse events following immunization (AEFIs), allergic reactions elicit the most concern, as they are often unpredictable and can be life-threatening. Their estimates range from one in 1,000,000 to one in 50,000 vaccine doses. This report describes allergic events following immunization reported from 2020 to 2021 in Puglia, a region in the South-East of Italy with around 4 million inhabitants. Its main objective is to describe the allergic safety profile of currently employed vaccines.

Materials and methods

This is a retrospective observational study. The study period spanned from January 2020 to December 2021, and the whole Apulian population was included in the study. Information regarding AEFIs reported in Puglia during the study period was gathered from the Italian Drug Authority's pharmacovigilance database (National Pharmacovigilance Network, RNF). The overall number of vaccine doses administered was extrapolated by the Apulian online immunization database (GIAVA). Reporting rates were calculated as AEFIs reported during a certain time span/number of vaccine doses administered during the same period.

Results

10,834,913 vaccine doses were administered during the study period and 95 reports of allergic AEFIs were submitted to the RNF (reporting rate 0.88/100,000 doses). 27.4% of the reported events (26/95) were classified as serious (reporting rate 0.24/100,000 doses). 68 out of 95 (71.6%) adverse events were at least partially resolved by the time of reporting and none of them resulted in the subject's death.

Conclusions

Allergic reactions following vaccination were rare events, thus confirming the favourable risks/benefits ratio for currently marketed vaccines.

COVID-19 vaccines associated with vasovagal malaise: A retrospective study in two mass vaccination centers and analysis of the WHO pharmacovigilance database

The association between COVID-19 vaccines and vasovagal malaise (VVM) has recently been reported in the literature. Our study aimed to describe COVID-19 vaccines associated VVM cases and to identify risk factors of COVID-19 vaccines associated VVM. To this end, we performed a descriptive study of VVM reports associated with COVID-19 vaccines from two French mass COVID-19 vaccination centers. We also extracted reports of VVM associated with all-COVID-19 vaccines in VigiBase®, the World Health Organization (WHO) pharmacovigilance database to analyze demographic data. In the two French mass vaccination center database, 408 entries reported VVM after the standard administration of tozinameran - Pfizer® (1.63/1,000 vaccinated persons). Of these cases, 213 (52.2%) occurred in women, and 193 (47.3%) occurred in the 18-29 year-old (yo) age group. In 232 cases (56.8%), patients had a history of anxiety related to needles or medical visits, 213 (52.2%) reported a fear of COVID-19 vaccination in particular, and 233 (57.1%) had a history of VVM. In VigiBase®, 336,291 notifications of COVID-19 vaccines associated with VVM were identified in the adult population during the period of analysis. The most reported age class was 18-44 years (52.4%), and women represented 71.7% of the reports. Reporting widely differed depending on the country. This study, performed in real-life conditions, highlights that VVM is associated with all-COVID-19 vaccines. Young age and history of anxiety related in young adults could be a triggering factor of vaccines-associated VVM. Further studies are needed to confirm our results.

Adverse reactions to inactivated COVID-19 vaccination in patients with chronic liver disease: The effect of anxiety

Studies have shown that patients with chronic liver disease are at a higher risk of contracting novel coronavirus pneumonia than healthy individuals, and many guidelines state that patients with chronic liver disease should be prioritized for COVID-19 vaccination, but there are a few studies on its safety in CLD patients. We aimed to evaluate the safety of the inactivated COVID-19 vaccine in patients with chronic liver disease, and the effect of anxiety on adverse reactions. A questionnaire survey for self-administered post-vaccination adverse reaction monitoring was conducted from June 17, 2021, to August 11, 2021, in patients with chronic liver disease attending a tertiary care hospital in Taizhou, China. We analyzed the data from of a total of 160 participants who scanned the QR code on social media to respond to the questionnaire. The overall incidence of adverse reactions after COVID-19 vaccination in patients with chronic liver disease was 44.4% (71/160), and the most common adverse reaction was local injection site reaction, accounting for 80.3% of adverse reactions (57/71). No serious adverse reactions were reported. Approximately 53.1% of the patients had anxiety about vaccination, and 51.8% of those who felt anxious reported adverse reactions. The safety of COVID-19 vaccination in patients with chronic liver disease is good, and there is a strong association between adverse reactions and vaccine anxiety. Pre-vaccination education for patients with vaccine anxiety and psychological counseling may reduce reports of adverse reactions and improve patients' confidence in the vaccine.

Adverse events following immunization of COVID-19 vaccine among children aged 6-11 years

Introduction

Starting in December 2021, the Indonesian Government has recommended inactivated SARS-CoV-2 vaccine (CoronaVac) for children aged 6-11 years. This study aims to determine the prevalence and determinant factors of adverse events following immunization (AEFI) of the first dose and the second dose of the COVID-19 vaccine among children aged 6-11 years old.

Materials and methods

We conducted a cross-sectional study in Bantul District, Yogyakarta, Indonesia, in February-March 2022. Data were collected by trained interviews with 1,093 parents of children 6-11 years old who received the first dose and the second dose of the COVID-19 vaccine. Data were analyzed with chi-square and logistic regression.

Results

The prevalence of AEFI in the first dose of the COVID-19 vaccine was 16.7%, while the second dose was 22.6%. The most common symptoms of AEFI at the first dose were local site pain and fever, while at the second dose were cough and cold. Determinants of AEFI of COVID-19 vaccination among children were girls with OR 1.31 (95% CI 1.0-1.7; P 0.04), mass-setting of vaccination with OR 0.70 (95% CI 0.5-0.9; P 0.01), the history of AEFI in childhood vaccination with OR 1.63 (95% CI 1.2-2.2; P < 0.01) and administering other vaccines within 1 month before COVID-19 vaccination, with OR 5.10 (95% CI 2.1-12.3 P < 0.01).

Conclusion

The prevalence of AEFI in the first and the second dose of inactivated COVID-19 vaccine was comparable to that reported in the clinical trial study and the communities. Risk communication should be provided to the child and their parents regarding the risk of mild AEFI of the COVID-19 vaccine, especially for children with a history of AEFI in childhood vaccination and who received other vaccines containing the same adjuvant with CoronaVac within 1 month. A mass-setting of vaccination should be taken as an advantage to educate parents about the risk of AEFI and also about the reporting pathways.

Change in adverse event reporting following immunization of hepatitis B vaccine among infants between 2013 to 2020 before and after the vaccine administration law in China

Background

Hepatitis B vaccine (HepB) has been routinely recommended as part of the immunization program in China and has had a satisfactory safety and effectiveness profile in protecting infants from hepatitis B virus infection. We evaluated the surveillance sensitivity and changes over time of AEFI reports related to HepB among infants based on the consistent national data before and after the introduction of vaccine administration law (LAW) from 2013 to 2020 in China.

Methods

AEFI records were extracted from the Chinese National AEFI Surveillance System from 2013 to 2020. According to the proportion of different kinds of HepB vaccines distributed, the annual administration data of the most distributed HepB produced by Bio-Kangtai and its corresponding adverse reaction reports were collected and analyzed. We categorized the time interval into the pre-LAW period (2013 to 2017), transition period (2018 to 2019), and LAW period (2020) to demonstrate the impact of LAW on the surveillance patterns of AEFIs.

Results

The annual AEFI rates increased from 3.1/100,000 to 14.8/100,000 over this period in total. The rate ratio for the post-LAW period and pre-LAW period was 2.19 (95%CI: 2.10, 2.29). Common reactions occupied 87.6% of the total reported AEFIs whose rate was recorded as 7.9/100,000. Rare reactions occupied 9.1% of the total AEFIs showing an average rate of 0.8/100,000, of which anaphylaxis accounted for over 80%, with the rate ratio of the transition period and LAW period as 1.36 (95%CI:1.22, 1.52) and 1.14 (95%CI:0.95, 1.35), respectively. Children receiving more than one vaccine showed a higher proportion of fever, anaphylaxis, and febrile convulsions, which were suggested to be a result of vaccine co-administration vaccines, such as the DPT and Polio vaccine.

Conclusion

Most reactions were mild and self-limited and the rates of rare more serious events remained stable. The LAW has largely increased the surveillance capability and sensitivity on AEFIs of HepB and also contributes to enhancing public confidence in HepB immunization. Hepatitis B vaccination is a safe and effective means of preventing the complications of hepatitis B disease and continuous standardized AEFI investigation and assessment of causal association should be maintained.

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

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

Understanding and experience of adverse event following immunization (AEFI) and its consequences among healthcare providers in Kebbi State, Nigeria: a qualitative study

Background

Vaccines used in the national immunization program are relatively safe and effective. However, no vaccine is perfectly safe. Therefore, adverse reactions may occur. This study aimed to investigate the understanding and experience of Adverse Event Following Immunization (AEFI) among healthcare workers and Routine Immunization (RI) officers.

Methods

Phenomenological qualitative study was conducted between June and September 2019, using a semi-structured question guide in Kebbi State, Northwest Nigeria. Face-to-face interviews were conducted with 12 RI providers, eight Expanded Program on Immunization (EPI) officers, and eight Disease Surveillance and Notification Officers. Thematic analysis was used to analyze the data. The interviews were transcribed and translated, then manually analyzed thematically.

Results

The knowledge level of healthcare providers on AEFI definition and classification varied and was suboptimal. Error during vaccination was the study participants' most frequently mentioned possible cause of AEFI. Persistent crying, fever, fainting, and swelling and tenderness at injection sites were the AEFI experienced by the healthcare providers in their careers. Block rejection, lower immunization uptake, loss of confidence in RI, attack on RI providers, discrimination of RI providers and divorce threats among spouses were the consequences of AEFI. Supportive supervision of the RI sessions, refresher training on safe injection for RI providers, and symptomatic treatment of clients with AEFI would prevent AEFI consequences. Also, educating caregivers, community sensitization, and dialogue would minimize the consequences of AEFI.

Conclusions

Evidence of a sub-optimal understanding of AEFI was established in this study. Hence, policymakers should consider regular refresher training on AEFI to ensure all RI providers have an optimal understanding of AEFI. Health education of caregivers and parents during RI sessions and community engagement should be considered to minimise AEFI consequences on the immunization program and the society.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12913-022-08133-9.

Investigation of the incidence of immunisation stress-related response following COVID-19 vaccination in healthcare workers

INTRODUCTION

Safe vaccination worldwide is critical to end the coronavirus disease 2019 (COVID-19) pandemic. We aimed to evaluate adverse reactions to vaccination using a web-based questionnaire and examine the risk factors for the occurrence of immunisation stress-related response (ISRR).

METHODS

We conducted a questionnaire survey using Google Form® among the employees of St. Marianna University Hospital who had received the COVID-19 vaccine between April 2021 and May 2021, 1 week after the first and second vaccinations. We developed and used a questionnaire to identify individuals with ISRR according to the World Health Organization diagnostic criteria. A generalised linear mixed model was constructed with ISRR onset as the dependent variable, subjects as the random factor, and each parameter as a fixed factor. A multivariate model was constructed using the forced imputation method with factors that were significant in the univariate analysis.

RESULTS

We enrolled 2,073 and 1,856 respondents in the first and second questionnaire surveys, respectively. Fifty-five and 33 ISRR cases were identified in the first and second vaccinations, respectively. In the univariate analysis, strong pre-vaccination anxiety (odds ratio [OR], 2.3; 95% confidence interval [CI], 1.30-4.12, p = 0·004) and history of allergy (OR, 1.6; 95% CI, 1.14-2.24, p = 0·007) were significant risk factors. Multivariate analysis also showed that strong pre-vaccination anxiety (OR, 2.1; 95% CI, 1.15-3.80, p = 0.016) and history of allergy (OR, 1.5; 95% CI, 1.09-2.15, p = 0.014) were significant risk factors.

CONCLUSIONS

Confirmation of allergy prior to vaccination and subsequent action are essential for addressing ISRR.

Investigation of a Cluster of Immunization Stress-Related Reactions after Coronavirus Disease 2019 (COVID-19) Vaccination, Thailand, 2021

On 28 April 2021, the investigation team of the Department of Disease Control, Ministry of Public Health, was notified of a cluster of people developing neurological symptoms following COVID-19 vaccination in a province in eastern Thailand. We conducted an investigation from 29 April to 20 May 2021 to confirm the outbreak, describe the epidemiological characteristics and identify possible risk factors. A matched case-control study was conducted. Matching factors were gender and vaccination site. A confirmed case was a person receiving COVID-19 vaccination in the province and developed at least one neurological symptom between 21 April and 20 May 2021. The rapid assessment of the vaccination cold chain system was carried out. We found a total of 36 cases out of 3920 vaccinees (attack rate = 0.92%), all cases were recovered and classified as an immunization stress-related reaction (ISRR) by the National AEFI Expert Committee. An analytic study found that menstruation was significantly associated with ISRR (AOR = 6.84 [95%CI = 1.09–42.91]). The environmental survey suggested that the cold chain system was properly managed. Further studies on other precipitating causes of ISRR should be performed. In terms of recommendation, health providers should pay greater attention to women menstruating during and after COVID-19 immunization.

Alterations in 18F-FDG PET/MRI and 15O-Water PET Brain Findings in Patients With Neurological Symptoms After COVID-19 Vaccination: A Pilot Study

PURPOSE

This study aimed to investigate functional abnormalities in the brain of patients with neurological adverse effects following COVID-19 (coronavirus disease 2019) vaccination using 18F-FDG PET/MRI and 15O-water PET.

METHODS

Eight patients (1 man and 7 women, aged 26-47 years [median age, 36.5 years]) who experienced neurological symptoms after the first COVID-19 vaccination underwent CT, MRI, 18F-FDG PET/MRI, and 15O-water PET of the brain. After 7 days, each patient underwent a follow-up 18F-FDG PET/MRI and 15O-water PET of the brain. Imaging data were analyzed using visual and semiquantitative analyses, which included a cluster subtraction workflow (P = 0.05).

RESULTS

There was no evidence of vascular abnormalities, acute infarction, or hemorrhage on the CT or MRI scans. On the 15O-water PET images, 1 patient had mildly significant decreases in perfusion in the bilateral thalamus and bilateral cerebellum, and another patient showed a diffuse increase in perfusion in the cerebral white matter. The visual and semiquantitative analyses showed hypometabolism in the bilateral parietal lobes in all 8 patients on both the first and follow-up 18F-FDG PET/MRI scans. Metabolic changes in the bilateral cuneus were also observed during the first visit; all patients exhibited neurological symptoms. Moreover, 6 patients showed hypometabolism, and 2 patients showed hypermetabolism.

CONCLUSION

All regions of metabolic abnormality were part of the fear network model that has been implicated in anxiety. Our study findings support the concepts of and provide evidence for the immunization stress-related response and the biopsychosocial model.

SARS-CoV-2 vaccine-associated-tinnitus: A review

The global vaccination drive against severe acute respiratory syndrome coronavirus-2 is being pursued at a historic pace. Unexpected adverse effects have been reported following vaccination, including thrombotic thrombocytopenia, myocarditis, amongst others. More recently, some cases of tinnitus are reported post-vaccination. According to the Vaccine Adverse Events Reporting System (VAERS), 12,247 cases of coronavirus post-vaccination tinnitus have been reported till September 14, 2021. To the best of our knowledge, this is the first review evaluating any otologic manifestation following vaccine administration and aims to evaluate the potential pathophysiology, clinical approach, and treatment. Although the incidence is infrequent, there is a need to understand the precise mechanisms and treatment for vaccine-associated-tinnitus.

Immunization Stress-Related Responses: Mitigating Patient Fears and Associated Side Effects Amidst a Global Vaccination Effort

The event of receiving a vaccine can lead to feelings of stress and anxiety for many patients and may present as adverse events. With coronavirus disease 2019 (COVID-19) mass vaccination efforts, adverse events following immunization, including immunization stress-related reactions (ISRR), have subsequently increased. Traditionally rare, but increasingly common, cluster events have also become a concern. Demonstrated in recent publications by Hause et al. concerning Janssen (Johnson & Johnson) COVID-19 vaccine clinics, these adverse events can lead to personal apprehension towards receiving vaccines, as well as public distrust towards the immunization process. To combat ISRRs, mass vaccination clinics across the United States must create administration protocols to mitigate these responses. Anticipation and swift management can play a substantial role in minimizing frequency and severity of these reactions and prevent future vaccine hesitancy.

Interpretation of vaccine associated neurological adverse events: a methodological and historical review

As a result of significant recent scientific investment, the range of vaccines available for COVID-19 prevention continues to expand and uptake is increasing globally. Although initial trial safety data have been generally reassuring, a number of adverse events, including vaccine induced thrombosis and thrombocytopenia (VITT), have come to light which have the potential to undermine the success of the vaccination program. However, it can be difficult to interpret available data and put these into context and to communicate this effectively. In this review, we discuss contemporary methodologies employed to investigate possible associations between vaccination and adverse neurological outcomes and why determining causality can be challenging. We demonstrate these issues by discussing relevant historical exemplars and explore the relevance for the current pandemic and vaccination program. We also discuss challenges in understanding and communicating such risks to clinicians and the general population within the context of the 'infodemic' facilitated by the Internet and other media.

The Rise of Functional Tic-Like Behaviors: What Do the COVID-19 Pandemic and Social Media Have to Do With It? A Narrative Review

BACKGROUND

There has been a rise in explosive onset of tic-like behaviors during the COVID-19 pandemic. Historically, this is an uncommon phenomenology of functional movement disorders across all ages. Both the psychological burden of the pandemic and social media usage have been implicated in the rise of these tic-like behaviors.

METHODS

This paper provides a narrative review of the literature on chronic tic disorders, functional tics, and mass functional illness with particular focus on the key distinguishing features, role of social media, and the role of COVID-19.

RESULTS

The COVID-19 pandemic has profoundly affected the mental health of many individuals, including children, adolescents, and their caregivers. Implementation of lockdowns, lifestyle disruptions, school closures, and social distancing have driven a surge in social media and digital technology use. The combination of predisposing factors, the psychological burden of the COVID-19 pandemic, and social media are implicated in the rise and spread of tic-like behaviors; which may represent a modern-day form of mass functional illness. While many of the features overlap with functional tics, there are emerging distinctive features that are important to recognize. A more encompassing term, Functional Tic-Like Behaviors, is used to better reflect multiple contributing factors.

CONCLUSION

Knowledge of these differences is essential to mitigate downstream health effects and poor outcomes.

Hospital-based observational study of neurological disorders in patients recently vaccinated with COVID-19 mRNA vaccines

PURPOSE

We describe the spectrum of acute neurological disorders among hospitalized patients who recently had COVID-19 mRNA vaccination.

METHOD

We performed a prospective study at 7 acute hospitals in Singapore. Hospitalized patients who were referred for neurological complaints and had COVID-19 mRNA vaccines, BNT162b2 and mRNA-1273, in the last 6 weeks were classified into central nervous system (CNS) syndromes, cerebrovascular disorders, peripheral nervous system (PNS) disorders, autonomic nervous system (ANS) disorders and immunization stress-related responses (ISRR).

RESULTS

From 30 December 2020 to 20 April 2021, 1,398,074 persons (median age 59 years, 54.5% males) received COVID-19 mRNA vaccine (86.7% BNT162b2, 13.3% mRNA-1273); 915,344(65.5%) completed 2 doses. Four hundred and fifty-seven(0.03%) patients were referred for neurological complaints [median age 67(20-97) years, 281(61.5%) males; 95.8% received BNT162b2 and 4.2% mRNA-1273], classified into 73(16.0%) CNS syndromes, 286(62.6%) cerebrovascular disorders, 59(12.9%) PNS disorders, 0 ANS disorders and 39(8.5%) ISRRs. Eleven of 27 patients with cranial mononeuropathy had Bell's palsy. Of 33 patients with seizures, only 4 were unprovoked and occurred within 2 weeks of vaccination. All strokes occurred among individuals with pre-existing cardiovascular risk factors. We recorded 2 cases of cerebral venous thrombosis; none were vaccine-induced thrombotic thrombocytopenia. Five had mild flares of immune-mediated diseases.

CONCLUSION

Our observational study does not establish causality of the described disorders to vaccines. Though limited by the lack of baseline incidence data of several conditions, we observed no obvious signal of serious neurological morbidity associated with mRNA vaccination. The benefits of COVID-19 vaccination outweigh concerns over neurological adverse events.

Vaccine safety in the next decade: why we need new modes of trust building

Among the realm of highly varied vaccine perceptions and concerns expressed by publics around the world, vaccine safety is the most frequently cited. While many of the safety questions raised have substantial evidence to address the concerns, vaccines do have small risks, and need vigilant and responsive systems to address them. With more and more new vaccines, combinations of vaccines and new technologies to develop and deliver them, new safety concerns will arise that need attention. Adding to this landscape is the dramatic impact which digital communication has had on how fast rumours and vaccine concerns can spread, making the task of the public health and scientific community even more pressing. One of the more recently characterised vaccine safety issues, now named 'immunisation stress-related-response,' has gained particularly high visibility given these highly globally connected social media networks. To better anticipate and address these rapidly shared vaccine safety concerns, a number of global efforts and local responses are being made. Co-created social media campaigns engaging parents and adolescents have been effective, while the WHO's Vaccine Safety Net (VSN) initiative has grown its global network to increase awareness about vaccines and contribute to building confidence in vaccines. The VSN reviews websites around the world to assess their quality and accuracy to ensure and promote access to trustworthy and science-based information on vaccine safety for internet users. These and the efforts of the multiple network partners are more crucial than ever to sustain public confidence in this evolving vaccine safety landscape.

Beyond fragmentary: A proposed measure for travel vaccination concerns

The travel medicine literature points to travelers' concerns as significant promoters of their under-vaccinations. Therefore, this study researches the hitherto understudied concept of vaccination concern and its theoretical scope in the international travel space. It attempts a conceptualization of the concept by delimiting its theoretical scope and proposes a measure for it. An exploratory sequential mixed-methods design was used to conduct four interlocking studies using data from a netnography, field interviews, and surveys among varied international travelers. A scale with six dimensions, comprising safety, efficacy, cost, time, access, and autonomy concerns were revealed. The scale significantly explained mainstream and segments-based tourists' uptake attitudes and behavior for their eligible vaccines. The findings suggest that anti-travel vax sentiments and public vax sentiments despite conceptually similar are considerably distinct. The broad nature of the scale and its prediction of travelers' vaccine uptake make it clinically relevant for tracking and resolving concerns for increased vaccine uptake.

Public preference for COVID-19 vaccines in China: A discrete choice experiment

BACKGROUND

As the coronavirus disease 2019 (COVID-19) pandemic is sweeping across the globe, there is an urgent need to develop effective vaccines as the most powerful strategy to end the pandemic. This study aimed to examine how factors related to vaccine characteristics, their social normative influence and convenience of vaccination can affect the public's preference for the uptake of the COVID-19 vaccine in China.

METHODS

An online discrete choice experiment (DCE) survey was administered to a sample of China's general population. Participants were asked to make a series of hypothetical choices and estimate their preference for different attributes of the vaccine. A mixed logit regression model was used to analyse the DCE data. Willingness to pay for each attribute was also calculated.

RESULTS

Data of 1236 participants who provided valid responses were included in the analysis. There was strong public preference for high effectiveness of the vaccine, followed by long protective duration, very few adverse events and being manufactured overseas. Price was the least important attribute affecting the public preference in selecting the COVID-19 vaccine.

CONCLUSIONS

The strong public preferences detected in this study should be considered when developing COVID-19 vaccination programme in China. The results provide useful information for policymakers to identify the individual and social values for a good vaccination strategy.

PATIENT OR PUBLIC CONTRIBUTION

The design of the experimental choices was fully based on interviews and focus group discussions participated by 26 Chinese people with diverse socio-economic backgrounds. Without their participation, the study would not be possible.

Surveillance of adverse events following immunization in the late 2010s: an overview of the importance, tools, and challenges

Immunization is one of the most effective measures to protect individuals and the population against vaccine-preventable diseases. Vaccines are safe and effective products, but like any other drug they can cause adverse events, which tend to become more visible as the diseases are controlled, eliminated, or eradicated. This study analyzed activities in the surveillance of adverse events following immunization (AEFI) based on data from the scientific literature, websites of immunization programs and health andregulatory agencies, and the authors' expertise in the areas of immunizations and pharmacovigilance. With the increase in the number of vaccines in the basic immunization schedule and expansion of the population's access, it has become essential to establish an efficient surveillance system for AEFI in Brazil. However, underreporting of cases in Brazil and in other countries hinders the detection of AEFI, especially rare events. Constantly updated information on vaccines' risks and benefits allows immunization programs to provide rapid and clear responses to rumors of AEFI. This ensures the system's reliability, especially in the face of the growing antivaccine movement and the increasing influence of social media in public opinion.

Immunization stress-related responses presenting as psychogenic non-epileptic seizures following HPV vaccination in Rio Branco, Brazil

IMPORTANCE

The absence of a positive diagnosis of psychogenic non-epileptic seizures (PNES) in immunization stress-related response (ISRR) clusters may have not only a direct impact on affected patients' health but may also reduce compliance to national vaccination programs. It is therefore crucial to develop efficient diagnostic tools and a feasible proposal for proper communication and treatment of ISRR.

PURPOSE

To explore the psychogenic nature of patients' convulsive seizures in a suspected outbreak of an ISRR cluster following human papillomavirus vaccination in Rio Branco, Brazil.

METHODS

Twelve patients with convulsive seizures were submitted to prolonged intensive video-electroencephalography monitoring, brain magnetic resonance imaging, cerebrospinal fluid diagnostic testing, laboratory subsidiary examinations, and complete neurological and psychiatric evaluations.

RESULTS

Ten patients received the positive diagnosis of PNES, and two patients received the diagnosis of idiopathic generalized epilepsy. No biological association was found between the HPV vaccine and the clinical problems presented by the patients.

CONCLUSIONS

Prolonged VEEG monitoring can contribute significantly to the positive diagnosis of PNES in ISRR clusters and to avoid hesitancy to vaccinate.

Lessons on causality assessment and communications from the 2019 South-East Asia Regional (SEAR) workshop on inter-country expert review of selected Adverse Events Following Immunization (AEFI) cases

BACKGROUND

Surveillance of AEFI is fundamental for improving safety and maintaining public support for vaccination. In SEAR, billions of doses of vaccine are given annually. The objective of the 2019 SEAR AEFI training workshop was to further strengthen in-country vaccine safety, assess capacity compared to 2014 and to better integrate communication into the AEFI causality assessment program.

METHODS

A 3 ½ day workshop with AEFI experts from all 11 SEAR countries. Participants outlined each county's AEFI data, critiqued their AEFI program, reviewed and critiqued causality assessment of 23 anonymized serious AEFI cases and proposed communication plans for each.

RESULTS

Between 2016 and 2018, over 2.9 billion doses of vaccine were given in SEAR. Compared to 2014, AEFI detection and causality assessment skills had improved. AEFI experts' communication planning skills markedly improved during the workshop. Good concordance was found between country causality assessment findings and the workshop critiques. A list of targeted recommendations (country, regional and global levels) arose from the workshop.

CONCLUSIONS

SEAR countries have much improved their AEFI detection and causality assessment expertise since 2014. Given the high volume of doses administered and the AEFI technical expertise, SEAR countries can well monitor safety of regionally produced vaccines. Integration of AEFI communication into AEFI causality assessment can help mitigate potential negative impacts of serious AEFIs.

Managing immunization stress-related response: A contributor to sustaining trust in vaccines

Adverse events following immunizations (AEFI) are important to identify and manage effectively so as to sustain trust in vaccines and optimize health. The AEFI category related to "anxiety about the immunization" was considered problematic as it did not adequately capture the range of stress responses that can occur. The currently used term for this category, immunization stress-related responses (ISRR), is broader, including the full spectrum of signs and symptoms that can arise in response to stress. ISRR can include vasovagal reactions (fainting), hyperventilation and functional neurological symptoms (e.g. weakness, nonepileptic seizures). It is based on a biopsychosocial framework in which biological (e.g. age, sex), psychological (e.g. preparedness, previous experiences, anxiety) and social factors (e.g. response by others, social media) interact to create an individual's stress response to the immunization process. New guidance is available on prevention, early detection and management of ISRRs which is summarized in the article.

Trends of Adverse Events Following Immunization (AEFI) Reports of Human Papillomavirus Vaccine in the Valencian Community—Spain (2008–2018)

Vaccine safety surveillance is essential in vaccination programs. We accomplished a descriptive study of surveillance AEFI-reporting rate in human papillomavirus (HPV) vaccine administered in the Valencian Community, Spain. Data were obtained from Spanish Pharmacovigilance Adverse Reactions Data (FEDRA). Reporting rates were calculated using local net doses distributed as the denominator. Trends were assessed using joinpoint regression with annual percent change (APC) reported. The AEFI-reports decreased between 2008 and 2018 in two periods, a fast decreasing rate from 2009 to 2011 (from 192.2 to 24.93 per 100000 doses; APC, −54.9%; 95%CI [−75.2; −17.7]), followed by a stable trend (−13% APC, 95%CI [−26.1; 2.4]). For the age group analysis, only the group aged 14–15 years old followed the same trend with -58.4% (95%CI [−73.9; −33.8]) APC during 2008–2011, and −8.8% (95%CI [−27.7; 15]) APC during 2011-2018. The majority of the reports (73.82%) were nonserious, involving reactions at or near the vaccination site, headache, and dizziness events. No death was reported. AEFI-reporting rates for HPV immunization in the Valencian Community have decreased considerably with two trend periods observed for girls aged 14–15 years old. Currently, the AEFI reporting rate shows a decreasing trend, perhaps following the Weber effect, and it could also be affected by media attention and coverage.

Immunization stress-related response - Redefining immunization anxiety-related reaction as an adverse event following immunization

The Council for the International Organizations of Medical Sciences (CIOMS) and WHO working group on pharmacovigilance defines five cause specific AEFI which includes an immunization anxiety-related reaction. Historically this term has been used to describe a range of symptoms and signs that may arise after immunization that are related to "anxiety" about the immunization. However, the term "anxiety" does not adequately capture all the elements of this cause specific AEFI. In 2015, the Global Advisory Committee for Vaccine Safety convened an expert working group with the purpose of redefining, preventing and managing this particular AEFI. The term "Immunization Stress-Related Response" is proposed to replace the former terminology. We present a manual that redefines this AEFI and present a framework for prevention, diagnosis and management in both an individual and also when such events occur as clusters and affect multiple individuals. Since such mass events can result in cessation of immunization programmes and/or a loss of public confidence, a communication response is essential.

Adverse events following Quadrivalent HPV vaccination reported in Sao Paulo State, Brazil, in the first three years after introducing the vaccine for routine immunization (March 2014 to December 2016)

In March 2014, the Quadrivalent human papilloma virus vaccine (4vHPV) was introduced in the female adolescents vaccination schedule of the National Immunization Program (PNI). A school-based vaccination program was implemented. We conducted a retrospective, descriptive study of the adverse events that took place after HPV vaccination, reported to the Adverse Events Following Immunization (AEFI) Information System in Sao Paulo State, from March 2014 to December 2016. All reports that fit the definitions of the 2014 National Manual on AEFI surveillance were included. AEFI risk was estimated by dividing the number of reports by the number of vaccine doses administered in the period. In the three-year period, 3,390,376 HPV vaccine doses were administered and 465 AEFI reports were registered, with 1,378 signs and symptoms. The reporting rate was 13.72 per 100,000 vaccine doses administered. The reports peaked in the first year of the program. The most frequent AEFI was syncope, with 5.7 reports per 100,000 doses administered, followed by dizziness, malaise, headache and nausea. Overall, 39 AEFI cases (8.4%) were classified as severe , with a reporting rate of 1.15 per 100,000 vaccine doses administered. Most cases were classified as severe because of hospitalization. Among them, there were cases of Guillain-Barré Syndrome, deep vein thrombosis, seizures and miscarriage. All young women recovered without sequelae. We identified five clusters of AEFI reports in four cities; the larger AEFI cluster occurred in the city of Bertioga, in September 2014, involving 13 female adolescents. Our data are in accordance with those from other countries and corroborate the safety of HPV vaccines.

The role of healthcare providers in HPV vaccination programs - A meeting report

The Human Papillomavirus (HPV) Prevention and Control Board convened a meeting in Bucharest, Romania (May 2018), to discuss the role of healthcare providers (HCPs) in prevention programs, with a focus on HPV vaccination and cervical cancer screening. International and local experts discussed the role that HCPs can play to increase the uptake of HPV vaccine and screening. Experts recommended: 1) increasing HCP norms of getting vaccinated; 2) training providers to make effective recommendations; 3) making culturally appropriate materials available, in local languages; and 4) centralizing and coordinating education and information material, to direct both HCPs and the general public to the best material available.

Did the New Italian Law on Mandatory Vaccines Affect Adverse Event Following Immunization's Reporting? A Pharmacovigilance Study in Southern Italy

Despite the well-recognized role of vaccines, coverage is far from optimal especially in children, representing a growing concern also in Italy. In order to reverse this emergency, the Italian Ministry approved in July 2017 the Law 119/2017, which renders mandatory and free of charge 10 vaccinations for patients aged 0–16. We aim to investigate the effects of the new Law 119/2017 on the reporting of adverse events following immunization related to mandatory vaccines into the Italian Pharmacovigilance database (Rete Nazionale di Farmacovigilanza – RNF). Therefore, we analyzed the spontaneous reports of suspected adverse events following immunization recorded in Campania Region (South of Italy) from December 1, 2016, to March 31, 2018. During the study period, 69 reports, covering 179 AEFIs, related to mandatory vaccines were sent to Campania Pharmacovigilance Regional Center. A substantial increase in AEFIs reporting was observed after the adoption of Law 119/2017. Out of 69 reports, 62% reported AEFIs that were considered as not serious and 78% had a favorable outcome. Out of 179 AEFIs, more than half referred to the following SOC: “general disorders and administration site conditions,” “nervous system disorders,” and “psychiatric disorders.” The highest number of reports came from patient/citizen. After the adoption of the Law 119/2017, there was an increase in the number of reports (18 before the adoption of the Law vs. 51 after). According to reported AEFIs during the entire period, no worrying safety data have emerged. In our opinion, the increase in the number of AEFIs’ reports should be related to the increase in vaccination coverage as well as to the intense debate that has followed the new Law. In this context, the continuous monitoring of vaccine safety and the fully implementation of vaccine–vigilance programs play a key role in achieving higher confidence in immunization programs and optimal vaccination coverage rate.

Cluster anxiety-related adverse events following immunization (AEFI): An assessment of reports detected in social media and those identified using an online search engine

BACKGROUND

Adverse events following immunization (AEFI) arising from anxiety have rarely been reported as a cluster(s) in the setting of a mass vaccination program. Reports of clusters of anxiety-related AEFIs are understudied. Social media and the web may be a resource for public health investigators.

METHODS

We searched Google and Facebook separately from Atlanta and Geneva to identify reports of cluster anxiety-related AEFIs. We reviewed a sample of reports summarizing year, country/setting, vaccine involved, patient symptoms, clinical management, and impact to vaccination programs.

RESULTS

We found 39 reports referring to 18 unique cluster events. Some reports were only found based on the geographic location from where the search was performed. The most common vaccine implicated in reports was human papillomavirus (HPV) vaccine (48.7%). The majority of reports (97.4%) involved children and vaccination programs in school settings or as part of national vaccination campaigns. Five vaccination programs were reportedly halted because of these cluster events. In this study, we identified 18 cluster events that were not published in traditional scientific peer-reviewed literature.

CONCLUSIONS

Social media and online search engines are useful resources for identifying reports of cluster anxiety-related AEFIs and the geographic location of the researcher is an important factor to consider when conducting these studies. Solely relying upon traditional peer-reviewed journals may seriously underestimate the occurrence of such cluster events.