Anaphylaxis rates associated with COVID-19 vaccines are comparable to those of other vaccines

Cutaneous reactions to vaccination

Vaccination is a fundamental principle of preventive health care. Administration of the vaccine, which contains the antigen(s) of a pathogen, activates the immune system and provides protection against infection. The immunogenicity and allergenicity of a vaccine may lead to various adverse reactions, depending on the responsiveness and susceptibility of the vaccinated individual. Cutaneous adverse events are among the most common and can manifest as various local or generalized vaccination reactions. Understanding their pathogenesis and clinical manifestations is essential for therapy, for further diagnostic clarification if necessary, and for managing any booster vaccination that may be required. Appropriate dermatological expertise therefore plays a crucial role in managing patients with a history of vaccination reactions.

Post-Vaccination Anaphylaxis in Adults: A Systematic Review and Meta-Analysis

BACKGROUND/OBJECTIVES

Vaccines have been recognized as one of the most effective public health interventions. However, vaccine-associated anaphylaxis, although rare, is a serious adverse reaction. The incidence of anaphylaxis related to non-COVID-19 vaccines in adults remains underreported. This systematic review and meta-analysis aim to estimate the incidence of post-vaccination anaphylaxis across various vaccines in adults.

METHODS

A comprehensive literature search of PubMed, Embase, Scopus, and Web of Science identified studies on anaphylaxis following vaccination in adults (≥18 years), excluding COVID-19 vaccines. PRISMA 2020 guidelines were followed. The protocol was registered in PROSPERO in advance (ID CRD42024566928). Random-effects and fixed-effects models were used to pool data and estimate the logit proportion, with the logit-transformed proportion serving as the effect size, thereby allowing for the calculation of event rates.

RESULTS

A total of 37 studies were included in the systematic review, with 22 studies contributing to the meta-analysis, representing a combined population of 206,855,261 participants. Most studies focused on influenza vaccines (n = 15). Across all studies, 262 anaphylactic cases were reported, with 153 cases related to influenza vaccines, followed by herpes zoster virus vaccines (38 cases) and yellow fever vaccines (29 cases). Td/Tdap vaccine had the lowest rate (0.0001 per 100,000 participants). The overall random-effects model yielded a logit proportion of -10.45 (95% CI: -12.09 to -8.82, p < 0.001), corresponding to an event rate of 2.91 events per 100,000 subjects (95% CI: 0.56 to 14.73). Sensitivity analysis showed a higher incidence for influenza, hepatitis vaccines, and in vulnerable populations.

CONCLUSIONS

Anaphylaxis following vaccination in adults is rare but varies by vaccine type. Strengthened monitoring and preparedness are essential, especially in non-medical settings, to ensure a rapid response to anaphylaxis and maintain public confidence in vaccination programs.

Cardiovascular complications in vascular connective tissue disorders after COVID-19 infection and vaccination

BACKGROUND

COVID-19 infection and vaccination have been reported to confer an elevated risk for cardiovascular events (CVE). We sought to determine whether individuals with an underlying vascular connective tissue disorder including Marfan syndrome (MFS), Loeys-Dietz syndrome (LDS), or vascular Ehlers Danlos syndrome (vEDS) are at increased risk for cardiac events after COVID-19 infection or vaccination.

METHODS

325 respondents self-reported data through a cross-sectional, web-based survey available from 22 November 2021, through 15 March 2022 regarding COVID-19 illness and vaccinations, the occurrence of any CVE, and adverse events following vaccination. The data were analyzed using a Cox proportional hazards model with time varying indicators for COVID-19 illness/vaccination in the preceding 30 days.

RESULTS

COVID-19 illness was significantly associated with an increased rate of a new abnormal heart rhythm 30 days following infection. No other CVEs were reported in the 90 days after COVID-19 illness. We did not find evidence of an increased rate of any CVE in the 30 days following any COVID-19 vaccination dose.

CONCLUSION

In respondents with MFS, LDS, or vEDS, we uncovered no evidence of an increase in CVEs in the 30 days following COVID-19 illness, with the possible exception of dysrhythmia. In light of the absence of a substantial increase in self-reported CVEs in the 30 days following COVID-19 vaccination, these data are in keeping with the recommendation from the Marfan Foundation Professional Advisory Board that all eligible persons be vaccinated for COVID-19.

mRNA Vaccines Against COVID-19 as Trailblazers for Other Human Infectious Diseases

mRNA vaccines represent a milestone in the history of vaccinology, because they are safe, very effective, quick and cost-effective to produce, easy to adapt should the antigen vary, and able to induce humoral and cellular immunity.

METHODS

To date, only two COVID-19 mRNA and one RSV vaccines have been approved. However, several mRNA vaccines are currently under development for the prevention of human viral (influenza, human immunodeficiency virus [HIV], Epstein-Barr virus, cytomegalovirus, Zika, respiratory syncytial virus, metapneumovirus/parainfluenza 3, Chikungunya, Nipah, rabies, varicella zoster virus, and herpes simplex virus 1 and 2), bacterial (tuberculosis), and parasitic (malaria) diseases.

RESULTS

RNA viruses, such as severe acute respiratory syndrome coronavirus (SARS-CoV)-2, HIV, and influenza, are characterized by high variability, thus creating the need to rapidly adapt the vaccines to the circulating viral strain, a task that mRNA vaccines can easily accomplish; however, the speed of variability may be higher than the time needed for a vaccine to be adapted. mRNA vaccines, using lipid nanoparticles as the delivery system, may act as adjuvants, thus powerfully stimulating innate as well as adaptive immunity, both humoral, which is rapidly waning, and cell-mediated, which is highly persistent. Safety profiles were satisfactory, considering that only a slight increase in prognostically favorable anaphylactic reactions in young females and myopericarditis in young males has been observed.

CONCLUSIONS

The COVID-19 pandemic determined a shift in the use of RNA: after having been used in medicine as micro-RNAs and tumor vaccines, the new era of anti-infectious mRNA vaccines has begun, which is currently in great development, to either improve already available, but unsatisfactory, vaccines or develop protective vaccines against infectious agents for which no preventative tools have been realized yet.

Revaccination outcomes among adolescents and adults with suspected hypersensitivity reactions following COVID-19 vaccination: A Canadian immunization research network study

BACKGROUND

COVID-19 vaccination has been associated with anaphylaxis and hypersensitivity reactions. Infectious disease physicians and allergists in the Canadian Special Immunization Clinic (SIC) Network developed guidance for evaluating patients with adverse events following immunization (AEFI) including suspected hypersensitivity. This study evaluated management and adverse event recurrence following subsequent COVID-19 vaccinations.

METHODS

Individuals aged 12 years and older enrolled at participating SICs before February 28, 2023 who were referred for suspected or diagnosed hypersensitivity reaction following COVID-19 vaccination, or for prevaccination assessment of suspected allergy to a COVID-19 vaccine component were included. De-identified clinical assessments and revaccination data, captured in a centralized database, were analyzed. The Brighton Collaboration case definition (BCCD) for anaphylaxis (2023 version) was applied.

RESULTS

The analysis included 206 participants from 13 sites: 26 participants referred for pre-vaccination assessment and 180 participants referred for adverse events following COVID-19 vaccination (15/180 [8.3%] with BCCD confirmed anaphylaxis, 84 [46.7%] with immediate hypersensitivity symptoms not meeting BCCD, 33 [18.3%] with other diagnosed hypersensitivity reactions, and 48 [26.7%] participants with a final diagnosis of non-hypersensitivity AEFI). Among participants referred for AEFIs following COVID-19 vaccination, 166/180 (92.2%) were recommended for COVID-19 revaccination after risk assessment, of whom 158/166 (95.2%) were revaccinated (all with a COVID-19 mRNA vaccine). After revaccination, 1/15 (6.7%) participants with prior anaphylaxis, 1/77 (1.3%) with immediate hypersensitivity not meeting criteria for anaphylaxis and 1/24 (4.2%) with other physician diagnosed hypersensitivity developed recurrent AEFI symptoms that met the BCCD for anaphylaxis. All 26 participants referred pre-vaccination, including 9 (34.6%) with history of polyethylene glycol-asparaginase reactions, were vaccinated without occurrence of immediate hypersensitivity symptoms.

CONCLUSIONS

Most individuals in this national cohort who experienced a hypersensitivity event following COVID-19 vaccination and were referred for specialist review were revaccinated without AEFI recurrence, suggesting that specialist evaluation can facilitate safe revaccination.

Adverse effects of COVID-19 vaccine in the paediatric population: a focus on the cardiovascular system

The COVID-19 pandemic had an unprecedented impact on healthcare systems and exists globally. To control pandemic progression, COVID-19 vaccines were developed and licensed for use in the adult population in early 2021 and became available in paediatric cohorts several months later. Since then, several studies have reported adverse events and severe adverse events in the adult and paediatric cohorts. The question remains whether there exists a significant risk to paediatric COVID-19 vaccination. This study reviews the classification and presentation of severe adverse events and discusses relevant reports in the literature. An emphasis is put on cardiovascular severe adverse events and adverse events. This paper also provides current and future perspectives relative to the pandemic, its control, and the future of vaccine immunology.

Vaccines and allergy: Back to the right places

Hypersensitivity reactions represent one of the most common causes of hesitancy for adherence to national vaccination programs. The majority of hypersensitivity reactions after vaccination are mild, and anaphylaxis is reported to be rare, although it remains challenging to estimate the frequency attributed to each single vaccine, either because of the lower number of administered doses of less common vaccines, or the administration of simultaneous vaccine in most of the vaccination programs. Although literature remains scattered, international consensus guides clinicians in identifying patients who might need the administration of vaccines in protected environments due to demonstrated hypersensitivity to vaccine components or adjuvants. Here we provide the current guidance on hypersensitivity reactions to vaccines and on vaccination of children with allergy disorders.

Incidence and management of the main serious adverse events reported after COVID-19 vaccination

Coronavirus disease 2019 (COVID-19) caused by the severe acute respiratory syndrome coronavirus 2n first appeared in Wuhan, China in 2019. Soon after, it was declared a pandemic by the World Health Organization. The health crisis imposed by a new virus and its rapid spread worldwide prompted the fast development of vaccines. For the first time in human history, two vaccines based on recombinant genetic material technology were approved for human use. These mRNA vaccines were applied in massive immunization programs around the world, followed by other vaccines based on more traditional approaches. Even though all vaccines were tested in clinical trials prior to their general administration, serious adverse events, usually of very low incidence, were mostly identified after application of millions of doses. Establishing a direct correlation (the cause-effect paradigm) between vaccination and the appearance of adverse effects has proven challenging. This review focuses on the main adverse effects observed after vaccination, including anaphylaxis, myocarditis, vaccine-induced thrombotic thrombocytopenia, Guillain-Barré syndrome, and transverse myelitis reported in the context of COVID-19 vaccination. We highlight the symptoms, laboratory tests required for an adequate diagnosis, and briefly outline the recommended treatments for these adverse effects. The aim of this work is to increase awareness among healthcare personnel about the serious adverse events that may arise post-vaccination. Regardless of the ongoing discussion about the safety of COVID-19 vaccination, these adverse effects must be identified promptly and treated effectively to reduce the risk of complications.

A randomized double-blinded trial to assess recurrence of systemic allergic reactions following COVID-19 mRNA vaccination

BACKGROUND

Systemic allergic reactions (sARs) following coronavirus disease 2019 (COVID-19) mRNA vaccines were initially reported at a higher rate than after traditional vaccines.

OBJECTIVE

We aimed to evaluate the safety of revaccination in these individuals and to interrogate mechanisms underlying these reactions.

METHODS

In this randomized, double-blinded, phase 2 trial, participants aged 16 to 69 years who previously reported a convincing sAR to their first dose of COVID-19 mRNA vaccine were randomly assigned to receive a second dose of BNT162b2 (Comirnaty) vaccine and placebo on consecutive days in a blinded, 1:1 crossover fashion at the National Institutes of Health. An open-label BNT162b2 booster was offered 5 months later if the second dose did not result in severe sAR. None of the participants received the mRNA-1273 (Spikevax) vaccine during the study. The primary end point was recurrence of sAR following second dose and booster vaccination; exploratory end points included biomarker measurements.

RESULTS

Of 111 screened participants, 18 were randomly assigned to receive study interventions. Eight received BNT162b2 second dose followed by placebo; 8 received placebo followed by BNT162b2 second dose; 2 withdrew before receiving any study intervention. All 16 participants received the booster dose. Following second dose and booster vaccination, sARs recurred in 2 participants (12.5%; 95% CI, 1.6 to 38.3). No sAR occurred after placebo. An anaphylaxis mimic, immunization stress-related response (ISRR), occurred more commonly than sARs following both vaccine and placebo and was associated with higher predose anxiety scores, paresthesias, and distinct vital sign and biomarker changes.

CONCLUSIONS

Our findings support revaccination of individuals who report sARs to COVID-19 mRNA vaccines. Distinct clinical and laboratory features may distinguish sARs from ISRRs.

A HIV-1 Gp41 Peptide-Liposome Vaccine Elicits Neutralizing Epitope-Targeted Antibody Responses in Healthy Individuals

Background

HIV-1 vaccine development is a global health priority. Broadly neutralizing antibodies (bnAbs) which target the HIV-1 gp41 membrane-proximal external region (MPER) have some of the highest neutralization breadth. An MPER peptide-liposome vaccine has been found to expand bnAb precursors in monkeys.

Methods

The HVTN133 phase 1 clinical trial (NCT03934541) studied the MPER-peptide liposome immunogen in 24 HIV-1 seronegative individuals. Participants were recruited between 15 July 2019 and 18 October 2019 and were randomized in a dose-escalation design to either 500 mcg or 2000 mcg of the MPER-peptide liposome or placebo. Four intramuscular injections were planned at months 0, 2, 6, and 12.

Results

The trial was stopped prematurely due to an anaphylaxis reaction in one participant ultimately attributed to vaccine-associated polyethylene glycol. The immunogen induced robust immune responses, including MPER+ serum and blood CD4+ T-cell responses in 95% and 100% of vaccinees, respectively, and 35% (7/20) of vaccine recipients had blood IgG memory B cells with MPER-bnAb binding phenotype. Affinity purification of plasma MPER+ IgG demonstrated tier 2 HIV-1 neutralizing activity in two of five participants after 3 immunizations.

Conclusions

MPER-peptide liposomes induced gp41 serum neutralizing epitope-targeted antibodies and memory B-cell responses in humans despite the early termination of the study. These results suggest that the MPER region is a promising target for a candidate HIV vaccine.

A descriptive review on the real-world impact of Moderna, Inc. COVID-19 vaccines

INTRODUCTION

Since the original COVID-19 vaccines were developed, abundant clinical trial and real-world evidence evaluating the efficacy, effectiveness, and safety of COVID-19 vaccines has been collected. Knowledge of the relative benefits and risks of COVID-19 vaccines is essential for building trust within target populations, ensuring they remain effectively and safely protected against an enduring infectious threat.

AREAS COVERED

This descriptive review discusses the benefits and risks associated with marketed Moderna, Inc. mRNA-based COVID-19 vaccines, focusing on their real-world effectiveness and safety profiles in various age groups. Adverse events of interest and potential benefits of vaccination are reviewed, including reduced risk for severe COVID-19 and long-term health outcomes, reduced economic and societal costs, and reduced risk for SARS-CoV-2 transmission.

EXPERT OPINION

Post-marketing safety and real-world data for Moderna, Inc. COVID-19 mRNA vaccines strongly support a positive benefit - risk profile favoring vaccination across all age groups. Although COVID-19 is no longer considered a global health pandemic, health risks associated with SARS-CoV-2 infection remain high. Concerted efforts are required to engage communities and maintain protection through vaccination. Continued surveillance of emerging variants and monitoring of vaccine safety and effectiveness are crucial for ensuring sustained protection against SARS-CoV-2.

Pierre F, Karmali R, Mi X, Boyer J, Nieves M, Ison MG, Winter JN, Gordon LI, Ma S. Humoral Immunity After COVID-19 Vaccination in Chronic Lymphocytic Leukemia and Other Indolent Lymphomas: A Single-Center Observational Study

BACKGROUND

Chronic lymphocytic leukemia (CLL) and other non-Hodgkin's lymphomas (NHLs) lead to broad immunosuppression, conferring a greater risk for morbidity and mortality from SARS-CoV-2. Our study analyzed antibody (Ab) seropositivity from SARS-CoV-2 vaccination in patients with these cancers.

METHODS

In the final analysis, 240 patients were involved, and seropositivity was defined as a positive total or spike protein Ab.

RESULTS

Seropositivity was 50% in CLL, 68% in WM, and 70% in the remaining NHLs. Moderna vaccination led to higher seropositivity compared to Pfizer vaccination across all cancers (64% vs. 49%; P = .022) and specifically CLL patients (59% vs. 43%; P = .029). This difference was not explainable by differences in treatment status or prior anti-CD20 monoclonal Ab therapy. In CLL patients, current or prior cancer therapy led to lower seropositivity compared to treatment-naïve patients (36% vs. 68%; P = .000019). CLL patients treated with Bruton's tyrosine kinase (BTK) inhibitors had better seropositivity after receiving the Moderna vaccination compared to Pfizer (50% vs. 23%; P = .015). Across all cancers, anti-CD20 agents within 1 year led to a lower Ab response compared to greater than one year (13% vs. 40%; P = .022), a difference which persisted after booster vaccination.

CONCLUSION

Antibody response is lower in patients with indolent lymphomas compared to the general population. Lower Ab seropositivity was found in patients with a history of anti-leukemic agent therapy or those immunized with Pfizer vaccine. This data suggests that Moderna vaccination may confer a greater degree of immunity against SARS-CoV-2 in patients with indolent lymphomas.

COVID-19 vaccines in 2023

Most Australian adults now have hybrid immunity to the SARS-CoV-2 virus, referring to a combination of protection from previous vaccine doses and past infection. Protection from both vaccination and past infection wanes over time. Booster doses are recommended to ensure that those who are at increased risk of severe COVID-19 remain protected. The optimal timing of future booster doses to maintain adequate protection against severe illness is not yet known. Older age remains the most important risk factor for severe COVID-19, including in the current Omicron variant era. The original COVID-19 vaccines are monovalent vaccines based on the ancestral strain of the SARS-CoV-2 virus. Bivalent vaccines have been developed based on earlier Omicron subvariants (BA.1 or BA.4-5) and the ancestral strain. These provide enhanced protection against severe illness from Omicron compared with the original monovalent vaccines. Updated monovalent vaccines based on a more recent Omicron subvariant (XBB.1.5) have been developed. COVID-19 vaccines have an excellent safety record, and serious adverse events are extremely rare.

Strengthening scientific credibility in the face of misinformation and disinformation: Viable solutions

Despite numerous attempts to mitigate their spread, misinformation and disinformation are rampant on social media and other public networks, posing a substantial risk to public health and individual well-being. A concerted, multi-channel approach is required to effectively tackle this evolving problem. This paper outlines potential strategies and actionable plans to improve the response to misinformation and disinformation by stakeholders from various healthcare ecosystems.

Oral adverse events following COVID-19 and influenza vaccination in Australia

Vaccine hesitancy, spurred by misinterpretation of Adverse Events (AEs), threatens public health. Despite sporadic reports of oral AEs post-COVID-19 vaccination, systematic analysis is scarce. This study evaluates these AEs using the Australian Database of Adverse Event Notifications (DAEN). A secondary analysis of DAEN data was conducted, with the analysis period commencing from the start of the COVID-19 vaccination rollout in February 2021 and the inception of the influenza vaccine database in 1971, both through until December 2022. The focus of the analysis was on oral AEs related to COVID-19 and influenza vaccines. Reports were extracted according to a predefined schema and then stratified by vaccine type, sex, and age. Oral paresthesia was the most common oral AE after COVID-19 vaccination (75.28 per 10,000 reports), followed by dysgeusia (73.96), swollen tongue (51.55), lip swelling (49.43), taste disorder (27.32), ageusia (25.85), dry mouth (24.75), mouth ulceration (18.97), oral hypoaesthesia (15.60), and oral herpes (12.74). While COVID-19 and influenza vaccines shared most oral AEs, taste-related AEs, dry mouth, and oral herpes were significantly more common after COVID-19 vaccination. mRNA vaccines yielded more oral AEs than other types. Females had higher oral AE incidence. Most oral AEs did not differ significantly between COVID-19 and influenza vaccination. However, specific oral AEs, particularly taste-related, dry mouth, and oral herpes, were more prevalent after COVID-19 vaccination compared with seasonal influenza, especially in females and mRNA vaccine recipients.

Updated guidance regarding the risk of allergic reactions to COVID-19 vaccines and recommended evaluation and management: A GRADE assessment and international consensus approach

This guidance updates 2021 GRADE (Grading of Recommendations Assessment, Development and Evaluation) recommendations regarding immediate allergic reactions following coronavirus disease 2019 (COVID-19) vaccines and addresses revaccinating individuals with first-dose allergic reactions and allergy testing to determine revaccination outcomes. Recent meta-analyses assessed the incidence of severe allergic reactions to initial COVID-19 vaccination, risk of mRNA-COVID-19 revaccination after an initial reaction, and diagnostic accuracy of COVID-19 vaccine and vaccine excipient testing in predicting reactions. GRADE methods informed rating the certainty of evidence and strength of recommendations. A modified Delphi panel consisting of experts in allergy, anaphylaxis, vaccinology, infectious diseases, emergency medicine, and primary care from Australia, Canada, Europe, Japan, South Africa, the United Kingdom, and the United States formed the recommendations. We recommend vaccination for persons without COVID-19 vaccine excipient allergy and revaccination after a prior immediate allergic reaction. We suggest against >15-minute postvaccination observation. We recommend against mRNA vaccine or excipient skin testing to predict outcomes. We suggest revaccination of persons with an immediate allergic reaction to the mRNA vaccine or excipients be performed by a person with vaccine allergy expertise in a properly equipped setting. We suggest against premedication, split-dosing, or special precautions because of a comorbid allergic history.

COVID-19, post-acute COVID-19 syndrome (PACS, "long COVID") and post-COVID-19 vaccination syndrome (PCVS, "post-COVIDvac-syndrome"): Similarities and differences

Worldwide there have been over 760 million confirmed coronavirus disease 2019 (COVID-19) cases, and over 13 billion COVID-19 vaccine doses have been administered as of April 2023, according to the World Health Organization. An infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can lead to an acute disease, i.e. COVID-19, but also to a post-acute COVID-19 syndrome (PACS, "long COVID"). Currently, the side effects of COVID-19 vaccines are increasingly being noted and studied. Here, we summarise the currently available indications and discuss our conclusions that (i) these side effects have specific similarities and differences to acute COVID-19 and PACS, that (ii) a new term should be used to refer to these side effects (post-COVID-19 vaccination syndrome, PCVS, colloquially "post-COVIDvac-syndrome"), and that (iii) there is a need to distinguish between acute COVID-19 vaccination syndrome (ACVS) and post-acute COVID-19 vaccination syndrome (PACVS) - in analogy to acute COVID-19 and PACS ("long COVID"). Moreover, we address mixed forms of disease caused by natural SARS-CoV-2 infection and COVID-19 vaccination. We explain why it is important for medical diagnosis, care and research to use the new terms (PCVS, ACVS and PACVS) in order to avoid confusion and misinterpretation of the underlying causes of disease and to enable optimal medical therapy. We do not recommend to use the term "Post-Vac-Syndrome" as it is imprecise. The article also serves to address the current problem of "medical gaslighting" in relation to PACS and PCVS by raising awareness among the medical professionals and supplying appropriate terminology for disease.

Anaphylactic Reactions to COVID-19 Vaccines: An Updated Assessment Based on Pharmacovigilance Data

This study aimed at producing an updated assessment of the incidence of anaphylaxis associated with COVID-19 vaccines based on pharmacovigilance data. Anaphylactic reaction and anaphylactic shock data post-COVID-19-vaccination reported from week 52, 2020 to week 1 or week 2, 2023 were collected from the VAERS and EudraVigilance databases, respectively, and analyzed comparatively. Incidence rates were calculated using the corresponding administered vaccine doses as denominators for all licensed vaccines and both platform types (mRNA or vectored). The latest data from the present analysis showed lower anaphylaxis incidence associated with COVID-19 vaccination compared to previous estimates from week 52, 2020 to week 39, 2021 (anaphylactic reaction: 8.96 (95% CI 8.80-9.11)/million doses overall (EEA: 14.19 (95% CI 13.92-14.47)/million/US: 3.17 (95% CI 3.03-3.31)/million); anaphylactic shock: 1.46 (95% CI 1.39-1.52)/million doses overall (EEA: 2.47 (95% CI 2.36-2.58)/million/US: 0.33 (95% CI 0.29-0.38)/million)). Incidence rates varied by vaccine and were higher as captured in EudraVigilance compared to the VAERS and for vectored compared to mRNA vaccines. Most reported cases had a favorable outcome. The extremely rare fatalities (overall rates across continents 0.04 (95% CI 0.03-0.06)/million doses for anaphylactic reaction and 0.02 (95% CI 0.01-0.03)/million vaccine doses for anaphylactic shock) were also associated with vector-rather than mRNA-based vaccines. The diminished incidence of anaphylaxis post-vaccination with COVID-19 vaccines offers assurance about their safety, as does the continuous potential adverse events monitoring through specialized pharmacovigilance databases.

mRNA COVID-19 Vaccine Anaphylaxis: Epidemiology, Risk Factors, and Evaluation

PURPOSE OF REVIEW

The COVID-19 vaccines have proved essential in our defense against the COVID-19 pandemic. However, concerns regarding allergic reactions to the vaccines persist to this day. Herein, we review the data regarding the frequency of allergic reactions to the COVID-19 vaccines, the epidemiology, and the management of patients reporting vaccine allergic reactions.

RECENT FINDINGS

Although initial reports emphasized a high risk of anaphylaxis to the COVID-19 vaccines, more recent data demonstrate similar rates of anaphylaxis to the COVID-19 vaccines as to other vaccines. Alternative explanations for increased rates of apparent allergic reactions are discussed, including the role for stress-related and nocebo responses. COVID-19 vaccines and mRNA vaccine technology are overwhelmingly safe and well-tolerated by most patients. Careful history and case review will enable the discerning physician to safely vaccinate most patients. Rare patients with objective signs and symptoms of anaphylaxis may be candidates for alternatives to vaccination including monoclonal antibodies.

Anaphylaxis rates following mRNA COVID-19 vaccination in children and adolescents: Analysis of data reported to EudraVigilance

AIM

The present study aimed to estimate the anaphylaxis rates following mRNA COVID-19 vaccination in children and adolescents in Europe.

METHODS

We retrieved data on 371 anaphylaxis cases following mRNA COVID-19 vaccination in children ≤ 17 years old notified to EudraVigilance as of October 8, 2022. Overall, 27,120,512 doses of BNT162b2 vaccine and 1,400,300 doses of mRNA-1273 vaccine have been delivered to children during the study period.

RESULTS

The overall mean anaphylaxis rate was 12.81 [95% confidence interval (CI): 11.49-14.12] per 10⁶ mRNA vaccine doses [12.14 (95% CI: 6.37-17.91) per 10⁶ doses for mRNA-1273 and 12.84 (95% CI: 11.49-14.19) per 10⁶ doses for BNT162b2]. Children 12-17 years old accounted for 317 anaphylaxis cases, followed by 48 cases in children 3-11 years old, and 6 cases in children 0-2 years old. Children 10-17 years old had a mean anaphylaxis rate of 13.52 (95% CI: 12.03-15.00) cases per 10⁶ mRNA vaccine doses and children 5-9 years old had a mean anaphylaxis rate of 9.51 (95% CI: 6.82-12.20) cases per 10⁶ mRNA vaccine doses. There were two fatalities, both in the 12-17 years age group. The fatal anaphylaxis rate was 0.07 cases per 10⁶ mRNA vaccine doses.

CONCLUSIONS

Anaphylaxis is a rare adverse event after receiving an mRNA COVID-19 vaccine in children. Continuous surveillance of serious adverse events is needed to guide vaccination policies as we move towards SARS-CoV-2 endemicity. Larger real-world studies on COVID-19 vaccination in children, using clinical case confirmation, are imperative.

VelcroVax: a "Bolt-On" Vaccine Platform for Glycoprotein Display

Having varied approaches to the design and manufacture of vaccines is critical in being able to respond to worldwide needs and newly emerging pathogens. Virus-like particles (VLPs) form the basis of two of the most successful licensed vaccines (against hepatitis B virus [HBV] and human papillomavirus). They are produced by recombinant expression of viral structural proteins, which assemble into immunogenic nanoparticles. VLPs can be modified to present unrelated antigens, and here we describe a universal "bolt-on" platform (termed VelcroVax) where the capturing VLP and the target antigen are produced separately. We utilize a modified HBV core (HBcAg) VLP with surface expression of a high-affinity binding sequence (Affimer) directed against a SUMO tag and use this to capture SUMO-tagged gp1 glycoprotein from the arenavirus Junín virus (JUNV). Using this model system, we have solved the first high-resolution structures of VelcroVax VLPs and shown that the VelcroVax-JUNV gp1 complex induces superior humoral immune responses compared to the noncomplexed viral protein. We propose that this system could be modified to present a range of antigens and therefore form the foundation of future rapid-response vaccination strategies. IMPORTANCE The hepatitis B core protein (HBc) forms noninfectious virus-like particles, which can be modified to present a capturing molecule, allowing suitably tagged antigens to be bound on their surface. This system can be adapted and provides the foundation for a universal "bolt-on" vaccine platform (termed VelcroVax) that can be easily and rapidly modified to generate nanoparticle vaccine candidates.

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.

mRNA vaccines: The future of prevention of viral infections?

Messenger RNA (mRNA) vaccines against COVID-19 are the first authorized biological preparations developed using this platform. During the pandemic, their administration has been proven to be a life-saving intervention. Here, we review the main advantages of using mRNA vaccines, identify further technological challenges to be met during the development of the mRNA platform, and provide an update on the clinical progress on leading mRNA vaccine candidates against different viruses that include influenza viruses, human immunodeficiency virus 1, respiratory syncytial virus, Nipah virus, Zika virus, human cytomegalovirus, and Epstein-Barr virus. The prospects and challenges of manufacturing mRNA vaccines in low-income countries are also discussed. The ongoing interest and research in mRNA technology are likely to overcome some existing challenges for this technology (e.g., related to storage conditions and immunogenicity of some components of lipid nanoparticles) and enhance the portfolio of vaccines against diseases for which classical formulations are already authorized. It may also open novel pathways of protection against infections and their consequences for which no safe and efficient immunization methods are currently available.

Recent developments in the immunopathology of COVID-19

There has been an important change in the clinical characteristics and immune profile of Coronavirus disease 2019 (COVID-19) patients during the pandemic thanks to the extensive vaccination programs. Here, we highlight recent studies on COVID-19, from the clinical and immunological characteristics to the protective and risk factors for severity and mortality of COVID-19. The efficacy of the COVID-19 vaccines and potential allergic reactions after administration are also discussed. The occurrence of new variants of concerns such as Omicron BA.2, BA.4, and BA.5 and the global administration of COVID-19 vaccines have changed the clinical scenario of COVID-19. Multisystem inflammatory syndrome in children (MIS-C) may cause severe and heterogeneous disease but with a lower mortality rate. Perturbations in immunity of T cells, B cells, and mast cells, as well as autoantibodies and metabolic reprogramming may contribute to the long-term symptoms of COVID-19. There is conflicting evidence about whether atopic diseases, such as allergic asthma and rhinitis, are associated with a lower susceptibility and better outcomes of COVID-19. At the beginning of pandemic, the European Academy of Allergy and Clinical Immunology (EAACI) developed guidelines that provided timely information for the management of allergic diseases and preventive measures to reduce transmission in the allergic clinics. The global distribution of COVID-19 vaccines and emerging severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants with reduced pathogenic potential dramatically decreased the morbidity, severity, and mortality of COVID-19. Nevertheless, breakthrough infection remains a challenge for disease control. Hypersensitivity reactions (HSR) to COVID-19 vaccines are low compared to other vaccines, and these were addressed in EAACI statements that provided indications for the management of allergic reactions, including anaphylaxis to COVID-19 vaccines. We have gained a depth knowledge and experience in the over 2 years since the start of the pandemic, and yet a full eradication of SARS-CoV-2 is not on the horizon. Novel strategies are warranted to prevent severe disease in high-risk groups, the development of MIS-C and long COVID-19.

Death and Disability Reported with Cases of Vaccine Anaphylaxis Stratified by Administration Setting: An Analysis of the Vaccine Adverse Event Reporting System from 2017 to 2022

The serious nature of post-vaccination anaphylaxis requires healthcare professionals to be adequately trained to respond to these hypersensitivity emergencies. The aim of this study was to compare outcomes reported with cases of vaccine anaphylaxis stratified by administration setting. We queried reports in the Vaccine Adverse Event Reporting System (VAERS) database from 2017 to 2022 and identified cases involving anaphylaxis with an onset within one day of vaccine administration. The primary outcome was the combined prevalence of death or disability for each setting while the secondary outcome was the prevalence of hospitalization. Adjusted (age, sex, prior history of allergy, vaccine type) odds ratios (aOR) and associated 95% confidence intervals (CI) were calculated using logistic regression analysis. A total of 2041 cases of anaphylaxis comprised the primary study cohort with representation in the sample from all 50 US states and the District of Columbia. The mean age was 43.3 ± 17.5 years, and most cases involved women (79.9%). Cases of anaphylaxis were reported after receiving a coronavirus vaccine (85.2%), influenza vaccine (5.9%), tetanus vaccine (2.2%), zoster vaccine (1.6%), measles vaccine (0.7%), and other vaccine (4.5%). Outcomes associated with reports of vaccine anaphylaxis included 35 cases of death and disability and 219 hospitalizations. Compared with all other settings, the aOR of death and disability when anaphylaxis occurred was 1.92 (95% CI, 0.86-4.54) in a medical provider's office, 0.85 (95% CI, 0.26-2.43) in a pharmacy and 1.01 (95% CI, 0.15-3.94) in a public health clinic. Compared with all other settings, the aOR of hospitalization when anaphylaxis occurred was 1.02 (95% CI, 0.71-1.47) in a medical provider's office, 1.06 (95% CI, 0.72-1.54) in a pharmacy, and 1.12 (95% CI, 0.61-1.93) in a public health clinic. An analysis of a national database across six years revealed no significant differences in the odds of death/disability and odds of hospitalization associated with post-vaccination anaphylaxis in the medical office, pharmacy, and public health clinic compared with all other settings. This study expands our understanding of the safety of immunization services and reinforces that all settings must be prepared to respond to such an emergency.

Anaphylaxis: Advances in the Past 10 Years

In the past 10 years, anaphylaxis has grown into its own special area of study within Allergy-Immunology, both at the bench and at the bedside. This review focuses on some of the most clinically relevant advances over the past decade. These include simplified and more inclusive diagnostic criteria for adults and children, uniform definition of biphasic anaphylaxis, and improved systems for objective severity grading. Studies reported in the past decade have led to improved understanding of normal and abnormal regulation of mast cell function, translating into better diagnostic and therapeutic approaches to patients with anaphylaxis. Research has provided improved recognition and treatment of mast cell disorders and has identified a new condition, hereditary α-tryptasemia, that may impact anaphylactic syndromes. We have learned to recognize new causes (α-gal), new pathways (Mas-related G protein-coupled receptor-X2), and many risk factors for severe anaphylaxis. The stability of epinephrine in autoinjectors was reported to be very good for several years after the labeled expiry date, and it can tolerate freezing and thawing. Repeated and prolonged exposure to excessive heat leads to degradation of epinephrine activity. New treatments to prevent severe anaphylaxis have been described, using new ways to block the IgE receptor or modulate intracellular signaling pathways.

COVID-19 Vaccination in Patients with Chronic Liver Disease

Vaccination against SARS-CoV-2 has become a central public health issue, primarily for vulnerable populations such as individuals with Chronic Liver Disease (CLD). Increased COVID-19-related mortality and disease severity has been noted in this subgroup of patients. Severe COVID-19 tends to further deregulate liver function in patients with chronic liver failure or cirrhosis and even reactivate hepatitis in people living with HBV or HCV. In addition, impaired hepatic function leads to several limitations in possible therapeutic interventions. Chronic hepatic dysregulation, along with the underlying cirrhosis-associated immune dysfunction (CAID), leads to a decreased immune response to vaccination that, in turn, may result in reduced efficacy rates and lowered lasting protection. According to current guidelines, timely vaccination and frequent booster shot administration are deemed necessary in this context. Vaccination-related adverse events are mostly mild in nature and similar to those reported in the general population, whereas the incidence of liver injury following vaccination is relatively rare. We aimed to review available evidence and recommendations associated with COVID-19 vaccination in patients with chronic liver disease, and provide insight to current issues and future directions.

Vaccine Vigilance System: Considerations on the Effectiveness of Vigilance Data Use in COVID-19 Vaccination

(1) Background: The safety of medicines has been receiving increased attention to ensure that the risks of taking medicines do not outweigh the benefits. This is the reason why, over several decades, the pharmacovigilance system has been developed. The post-authorization pharmacovigilance system is based on reports from healthcare professionals and patients on observed adverse reactions. The reports are collected in databases and progressively evaluated. However, there are emerging concerns about the effectiveness of the established passive pharmacovigilance system in accelerating circumstances, such as the COVID-19 pandemic, when billions of doses of new vaccines were administered without a long history of use. Currently, health professionals receive fragmented new information on the safety of medicines from competent authorities after a lengthy evaluation process. Simultaneously, in the context of accelerated mass vaccination, health professionals need to have access to operational information-at least on organ systems at higher risk. Therefore, the aim of this study was to perform a primary data analysis of publicly available data on suspected COVID-19 vaccine-related adverse reactions in Europe, in order to identify the predominant groups of reported medical conditions after vaccination and their association with vaccine groups, as well as to evaluate the data accessibility on specific syndromes. (2) Methods: To achieve the objectives, the data publicly available in the EudraVigilance European Database for Suspected Adverse Drug Reaction Reports were analyzed. The following tasks were defined to: (1) Identify the predominant groups of medical conditions mentioned in adverse reaction reports; (2) determine the relative frequency of reports within vaccine groups; (3) assess the feasibility of obtaining information on a possibly associated syndrome-myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). (3) Results: The data obtained demonstrate that the predominant medical conditions induced after vaccination are relevant to the following categories: (1) "General disorders and administration site conditions", (2) "nervous system disorders", and (3) "musculoskeletal and connective tissue disorders". There are more reports for mRNA vaccines, but the relative frequency of reports per dose administered, is lower for this group of vaccines. Information on ME/CFS was not available, but reports of "chronic fatigue syndrome" are included in the database and accessible for primary analysis. (4) Conclusions: The information obtained on the predominantly reported medical conditions and the relevant vaccine groups may be useful for health professionals, patients, researchers, and medicine manufacturers. Policymakers could benefit from reflecting on the design of an active pharmacovigilance model, making full use of modern information technologies, including big data analysis of social media and networks for the detection of primary signals and building an early warning system.

COVID-19 Vaccination in Korea: Past, Present, and the Way Forward

Since its first emergence in late 2019, severe acute respiratory syndrome coronavirus-2 has claimed more than 6.5 million lives worldwide and continues to infect hundreds of thousands of people daily. To combat this once-in-a-century disaster, several vaccines have been developed at unprecedented speeds. Novel vaccine platforms (messenger ribonucleic acid vaccines and adenoviral vector vaccines) have played a major role in the current pandemic. In Korea, six vaccines, including a domestically developed recombinant vaccine, have been approved. As in other countries, vaccines have been proven to be safe and highly effective in Korea. However, rare serious adverse events and breakthrough infections have undermined public trust in the vaccines, even while the benefits of vaccination far outweigh the risks. The rise of the omicron variant and the subsequent increase in excess mortality demonstrated that while vaccines are a key component of the pandemic response, it alone can fail without non-pharmaceutical interventions like masking and social distancing. The pandemic of coronavirus disease has revealed both the strengths and weaknesses of our healthcare system and pandemic preparedness. When the next pandemic arrives, improved risk communication and vaccine development should be prioritized. To enable timely vaccine development, it is essential to make strategic and sufficient investments in vaccine research and development.

Immediate Adverse Events Following COVID-19 Vaccination in Australian Pharmacies: A Retrospective Review

BACKGROUND

Four COVID-19 vaccines are approved for use in Australia: Pfizer-BioNTech BNT162b2 (Comirnaty), AstraZeneca ChAdOx1 (Vaxzevria), Moderna mRNA-1273 (Spikevax), and Novavax NVX-CoV2373 (Nuvaxovid). We sought to examine the type and management of immediate adverse events following immunisation (I-AEFI) after COVID-19 vaccination.

METHODS

Retrospective review of I-AEFI recorded between July 2021 and June 2022 in 314 community pharmacies in Australia.

RESULTS

I-AEFI were recorded in 0.05% (n = 526/977,559) of all COVID-19 vaccinations (highest: AstraZeneca (n = 173/161,857; 0.11%); lowest: Pfizer (n = 50/258,606; 0.02%)). The most common reactions were: (1) syncope, after the first dose of AstraZeneca (n = 105/67,907; 0.15%), Moderna (n = 156/108,339; 0.14%), and Pfizer (n = 22/16,287; 0.14%); and (2) Nausea/vomiting after the first dose of Pfizer (n = 9/16,287; 0.06%), Moderna (n = 55/108,339; 0.05%), and AstraZeneca (n = 31/67,907; 0.05%) vaccines. A total of 23 anaphylactic reactions were recorded (n = 23/977,559; 0.002%), and 59 additional I-AEFI were identified using MedDRA^® terminology. Pharmacists primarily managed syncope by laying the patient down (n = 227/342; 66.4%); nausea/vomiting was managed primarily by laying the patient down (n = 62/126; 49.2%), giving water (n = 38/126; 30.2%), or monitoring in the pharmacy (n = 29/126; 23.0%); anaphylactic reaction was treated with adrenaline (n = 18/23; 78.3%) and n = 13/23 (56.5%) anaphylactic reactions were treated with the combination of: administered adrenaline, called ambulance, and laid patient down.

CONCLUSION

The most commonly recorded I-AEFI was syncope after COVID-19 vaccination in pharmacy; I-AEFI are similar to those previously reported. Pharmacists identified and managed serious and non-serious I-AEFI appropriately and comprehensively.

Basophil Activation Test with Different Polyethylene Glycols in Patients with Suspected PEG Hypersensitivity Reactions

Allergic reactions to COVID-19 vaccine components are rare but should be considered. Polyethylene glycol (PEG) is responsible for anaphylaxis in mRNA vaccines. Skin tests have been used in the allergological work-up programs for COVID-19 vaccine evaluation. However, the reproducibility of the skin prick test is time-dependent and the reactivity declines over time. Therefore, we combined the administration of the skin tests with the basophil activation test (BAT) using PEG2000, PEG4000 and DMG-PEG2000, where the BAT was considered positive when the percentage of activated basophils was higher than 6%, 5% and 6.5%, for PEG 4000, PEG2000 and DMG-PEG2000, respectively. To this end, among the subjects that underwent allergy counseling at the Allergy Unit of our Institution during the 2020/2021 vaccination campaign, 13 patients had a suggested medical history of PEG/drug hypersensitivity and were enrolled together with 10 healthy donors. Among the enrolled patients 2 out of 13 tested patients were positive to the skin test. The BAT was negative in terms of the percentages of activated basophils in all analyzed samples, but the stimulation index (SI) was higher than 2.5 in 4 out of 13 patients. These data evidenced that, when the SI is higher than 2.5, even in the absence of positivity to BAT, the BAT to PEG may be a useful tool to be coupled to skin tests to evidence even low-grade reactions.

PEG allergy - A COVID-19 pandemic-made problem? A German perspective

Background

Polyethylene glycol (PEG) has been used for decades, but only caused allergic reactions exceptionally. Introduction of PEG-containing COVID-19 vaccines might have fostered public interest beyond medical reasoning.

Objectives

To investigate the impact of the SARS-CoV-2 pandemic on the public interest in PEG allergy in Germany and the published PEG allergy cases worldwide.

Methods

A retrospective longitudinal study was conducted to measure public interest in PEG allergy analyzing Google search volume in Germany from February 2018 to January 2022. Medically confirmed “PEG allergy” cases were analyzed by looking at the numbers of PubMed case reports and case series from 1977 until January 2022.

Results

Web results in Germany before COVID-19 show search volumes related to “PEG allergy/testing” was negligible, with 10 search queries per month. The pandemic led to a >200-fold increase from 250 queries 2 years before to 55 720 queries 2 years thereafter, reflecting tremendous public interest. Additionally, the maximum monthly search volume from before to during the pandemic increased immensely for “vaccination” (57-fold), “vaccination and adverse effects” (85-fold), “vaccination and allergy” (71-fold). In contrast, the increase of publication numbers for the search term “PEG allergy” was small from 2019 to 2021 (2.5-fold). Only a very low number of 211 cases with “PEG allergy” worldwide since 1977 could be identified.

Conclusion

PEG allergy became a topic of major public interest because of COVID-19 vaccination. Scientific publications have increased to a lesser extent, probably promoted by public awareness. Conversely, the overall number of cases published with PEG allergy remain very low. The current high demand for COVID-19 vaccination allergy testing is triggered by public interest instead of medical reasoning.

Safety after BBIBP-CorV (Sinopharm) COVID-19 Vaccine in Adolescents Aged 10-17 Years in Thailand

Coronavirus disease 2019 affected child health and impacted learning because of the resulting onsite school closures. This prospective cohort study included children aged 10-17 who received two 4 µg doses of BBIBP-CorV administered intramuscularly 21-28 days apart. To assess vaccine safety, 36,808 participants were then followed with paper- and web-based online questionnaire surveys that captured local and systemic reactogenicities following vaccine administration on days 1, 7, and 30. Among participants, 76% (27,880) reported reactogenicity within the first 24 h and 7 days following the first dose. Half (51.41%) of participants experienced pain at the injection site; the majority of cases were mild in severity. Injection site tenderness (37.93%) was another common local reaction. Fatigue (37.89%), myalgia (33.56%), and headache (26.76%) were the most common systemic reactions. On days 2-7 after the first dose, 25.85% of participants experienced adverse reactions. Following the second dose, reactogenicity was 7.6% and 1.09% within 24 h and between days 2-7. The majority of reactions were of mild to moderate severity. We report that two doses of the BBIBP-CorV caused mild to moderate side effects in adolescents in Thailand. The findings confirm the vaccine's safety profile in this age group.

Immediate hypersensitivity to COVID-19 vaccines: Focus on biological diagnosis

Soon after the release of the new anti-COVID mRNA vaccines, reports came in from the US and the UK of anaphylactic reactions. Fueled by the necessary caution toward these new vaccine platforms, these reports had a great impact and were largely commented upon in the scientific literature and global media. The current estimated frequency is of 5 cases per million doses. Very little biological data are presented in the literature to support the anaphylaxis diagnosis in these patients in addition to skin tests. Allergic reactions to vaccines are rare and mostly due to vaccine excipient. Therefore, the poly-ethylene-glycol (PEG) present in both mRNA formulation, and already known to be immunogenic, was soon suspected to be the potential culprit. Several hypersensitivity mechanisms to PEG or to other vaccine components can be suspected, even if the classical IgE-dependent anaphylaxis seems to be one of the most plausible candidates. In the early 2022, the international guidelines recommended to perform skin prick tests and basophil activation tests (BAT) in people experiencing allergic reaction to the first dose of COVID-19 vaccine or with a history of PEG allergy. The aim of this review is to discuss the main potential mechanisms of immediate allergy to COVID19 vaccines based on published data, together with the various techniques used to confirm or not sensitization to one component.

Asia Pacific perspectives on the second year of the COVID-19 pandemic: A follow-up survey

Background

The Coronavirus disease 2019 (COVID‐19) pandemic is currently in its third year. This follow‐up survey was commissioned by the Asia Pacific Association of Allergy Asthma and Clinical Immunology (APAAACI) Task Force on COVID‐19 to compare and contrast changes in the epidemiology, clinical profile, therapeutics and public health measures of the pandemic in the Asia Pacific region.

Methods

A questionnaire‐based survey comprising 32 questions was electronically sent out to all 15 member countries of APAAACI using Survey Monkey® from 1 December 2021 to 28 February 2022.

Results

Seventeen responses were received from 14/15 (93.4%) member countries and 3 individual members. Mild‐to‐moderate COVID‐19 predominated over severe infection, largely contributed by COVID‐19 vaccination programmes in the region. The incidence of vaccine adverse reactions in particular anaphylaxis from messenger ribonucleic acid (mRNA) vaccines was no longer as high as initially anticipated, although perimyocarditis remains a concern in younger males. Novel therapeutics for mild‐to‐moderate disease including neutralizing antibodies casirivimab/imdevimab (REGEN‐COV®) and sotrovimab (Xevudy®), anti‐virals Paxlovid® (nirmatrelvir and ritonavir) and Molnupiravir pre‐exposure prophylaxis for high‐risk persons with Tixagevimab and Cilgavimab (Evusheld) are now also available to complement established therapeutics (e.g., remdesivir, dexamethasone and baricitinib) for severe disease. In the transition to endemicity, public health measures are also evolving away from containment/elimination strategies.

Conclusions

With access to internationally recommended standards of care including public health preventive measures, therapeutics and vaccines among most APAAACI member countries, much progress has been made over the 2‐year period in minimizing the morbidity and mortality from COVID‐19 disease.

Approaches to pretransplant vaccination

PURPOSE OF REVIEW

The aim of this study was to summarize new data and perspectives in pretransplant vaccination, with a particular focus on COVID-19 vaccination and vaccination requirements.

RECENT FINDINGS

Pretransplant vaccination produces superior markers of immunity and is expected to have greater clinical benefit, compared with posttransplant vaccination. As such, efforts are underway to identify and characterize barriers to pretransplant vaccination, with a particular focus on COVID-19 vaccine hesitancy. Unfortunately, vaccine hesitancy is common in transplant patients, often motivated by individual side effect and safety concerns. COVID-19 vaccination requirements have been implemented in some centres, informed by ethical principles, including beneficence, utility and justice.

SUMMARY

Barriers to pretransplant vaccination can be understood in three categories: hard stops, including issues of vaccine availability, eligibility, safety and feasibility; soft stops, including issues of convenience, prioritization and care coordination; and volitional stops related to vaccine hesitancy and refusal. All of these barriers present opportunities for improvement based on recent data.

Incidence of immediate allergic reactions to mRNA COVID-19 vaccines in adults with drug allergies and other allergic disorders

Concerns have been raised about allergic reactions to messenger ribonucleic acid (mRNA) coronavirus disease 2019 (COVID-19) vaccines. A history of allergic reactions, including anaphylaxis to drugs, has been frequently reported in individuals with anaphylaxis to mRNA vaccines. To estimate the rate of immediate allergic reactions in patients with a history of drug allergy or other allergic disorders. We included adult patients who had received at least 1 dose of an mRNA COVID-19 vaccine at the Special Hospital for Pulmonary Diseases between March 1, 2021, and October 1, 2021, and who reported a history of drug allergy or other allergic diseases (asthma, allergic rhinitis, atopic dermatitis, food or insect venom allergy, mastocytosis, idiopathic anaphylaxis, acute or chronic urticaria, and/or angioedema). Immediate allergic reactions, including anaphylaxis, occurring within 4 hours of vaccination were recorded. Six immediate allergic reactions were noted in the cohort of 1679 patients (0.36%). One patient experienced anaphylaxis (0.06%), which resolved after epinephrine administration, and the other reactions were mild and easily treatable. Most patients with a history of allergies can safely receive an mRNA COVID-19 vaccine, providing adequate observation periods and preparedness to recognize and treat anaphylaxis.

Report of Adverse Effects Following Population-Wide COVID-19 Vaccination: A Comparative Study between Six Different Vaccines in Baja-California, Mexico

After emergency authorization, different COVID-19 vaccines were administered across Mexico in 2021, including mRNA, viral vector, and inactivated platform vaccines. In the state of Baja-California, 3,516,394 doses were administered, and 2285 adverse events (AE) were registered in the epidemiological surveillance system in 2021. Incidence rates per 100,000 doses were calculated for total, mild (local and systemic), and severe AE for each vaccine. Symptoms were compared between mRNA and viral vector/inactivated virus vaccines. The overall incidence rate for all AE was 64.98 per 100,000 administered doses; 79.05 AE per 100,000 doses for mRNA vaccines; and 56.9 AE per 100,000 doses for viral vector/inactivated virus vaccine platforms. AE were at least five times higher in recipients of the AstraZeneca vaccine from the Serum Institute of India (AZ from SII). Local injection site symptoms were more common in mRNA vaccines while systemic were more prevalent in viral vector/inactivated virus vaccines. Severe AE rates were similar across all administered vaccines (0.72–1.61 AE per 100,000 doses), except for AZ from SII, which documented 12.6 AE per 100,000 doses. Among 32 hospitalized severe cases, 28 (87.5%) were discharged. Guillain–Barré Syndrome was the most common serious AE reported (n = 7). Adverse events rates differed among vaccine manufacturers but were consistent with clinical trials and population-based reports in the literature.

Oral Adverse Events Following COVID-19 Vaccination: Analysis of VAERS Reports

Background

Oral adverse events (AEs) following COVID-19 vaccination have been sporadically reported during the previous months, warranting further investigation for their prevalence and suspected relationship with vaccine-elicited immune response.

Methods

A retrospective analysis using the Vaccine Adverse Event Reporting System (VAERS) data was conducted to evaluate AEs within the oral cavity (mucosa, tongue, lips, palate, dentition, salivary glands) and AEs involving taste and other sensations. Oral AEs reported after receiving COVID-19 vaccination (test group) and seasonal influenza vaccination (control group) were extracted and cross-tabulated to assess their relative prevalence.

Results

Among the 128 solicited (suspected) oral AEs, oral paresthesia (0.872%) was most reported after receiving COVID-19 vaccines, followed by the swelling of lips (0.844%), ageusia (0.722%), oral hypoesthesia (0.648%), swollen tongue (0.628%), and dysgeusia (0.617%). The reported prevalence of oral AEs was higher in the COVID-19 vaccine group than in the seasonal influenza group. The distribution pattern of the most reported oral AEs was similar for both COVID-19 and seasonal influenza vaccines. Female sex, older age (>39 years old), primer doses, and mRNA-based COVID-19 vaccines exhibited a higher reported prevalence of oral AEs.

Conclusion

Within the limitations of this study, COVID-19 vaccines were found to be associated with rare oral AEs that are predominantly similar to those emerging following seasonal influenza vaccines. The most commonly reported oral AEs were oral paraesthesia (mouth-tingling), lip swelling, and ageusia, representing various pathophysiologic pathways that remain unclear. Taste-related AEs should be acknowledged in the context of the COVID-19 pandemic and the public should be adequately informed about a potential taste dysfunction after receiving the COVID-19 vaccination. Dentists and dental teams need to be aware of the prevalence, severity, and prognosis of oral AEs to inform their patients and increase public confidence in vaccines.

Anaphylaxis and Related Events Post-COVID-19 Vaccination: A Systematic Review

The Coronavirus Disease 2019 (COVID-19), induced by the SARS CoV-2 virus, is responsible for a global pandemic following widespread transmission and death. Several vaccines have been developed to counter this public health crisis using both novel and conventional methods. Following approval based on promising efficacy and safety data, the AstraZeneca, Janssen, Moderna, Pfizer/BioNTech, and SinoVac vaccines have been administered globally among different populations with various reported side effects. Reports of life-threatening anaphylaxis following administration were of particular concern for both healthcare providers and the public. A systematic literature search using PubMed, Embase, Scopus, Web of Science, Science Direct, MedRxiv, and Lens.org databases identified relevant studies reporting anaphylaxis following vaccine administration. This systematic review includes 41 studies reporting anaphylaxis out of 19908 studies that were retrieved for screening. A total of 7942 cases, including 43 deaths, were reported across 14 countries. Most cases occurred following the administration of the first dose. Importantly, the benefits of vaccination far outweigh the risks of anaphylaxis. Subsequently, as populations continue to get vaccinated, it is important for healthcare providers to be able to recognize individuals at risk of developing anaphylaxis. Furthermore, they must be familiar with both the clinical hallmarks and treatment of anaphylactic reactions to minimize long term sequalae and prevent death in vaccinated individuals. This article is protected by copyright. All rights reserved.

Risk Stratification through Allergy History: Single-centre Experience of Specialised COVID-19 Vaccine Clinic

Anaphylaxis is a rare side-effect of Covid-19 vaccines. In order to (a) provide direct advice and reassurance to certain persons with a history of anaphylaxis/complex allergy, in addition to that available in national guidelines, and (b) to provide a medically supervised vaccination, a specialist regional vaccine allergy clinic was established. The main objective was to determine if risk stratification through history can lead to safe COVID-19 vaccination for maximum population coverage. A focused history was taken to establish contraindications to giving COVID-19 vaccines. People who reported a high-risk allergy history were given a vaccine not containing the excipient thought to have directly caused previous anaphylaxis. All vaccinees were monitored for 30 minutes after administration. 206 people were vaccinated between 6 July 2021 and 31 August 2021; Comirnaty (Pfizer-BioNTech) (n=34), and Janssen (n=172). 78% were women. Ninety-two people (45%) reported a high-risk allergy history. There were no cases of anaphylaxis. Three people developed urticaria and one of these also developed transient tachycardia. One vaccinee developed a pseudoseizure. Two of 208 people (<1%) referred during this time declined vaccination based on personal preference, despite assessment of low clinical risk. In our experience, all vaccinees with high-risk allergy histories were administered Pfizer BioNTech or Janssen Covid-19 vaccines uneventfully following screening based on allergy-focussed history. Our data support that drug allergy is not associated with a higher risk of vaccine-related anaphylaxis but may act to guide administration of alternate vaccines to people with polyethylene glycol/polysorbate 80/trometamol allergies or anaphylaxis after first dose.

Adverse Reactions to Anti-Infective Vaccines: an Emerging Problem in the COVID-19 Era

Purpose of review

Vaccines are an essential tool for preventing infectious diseases and reducing associated morbidity and mortality. Vaccination has a significant impact at both individual and community levels, and COVID‐19 vaccination programs are a new example of the great value of this public health strategy. However, adverse reactions, especially severe reactions such as anaphylaxis, prevent these programs from progressing properly, thus limiting vaccination uptake in the population.

Recent findings

The frequency of reactions and types of vaccine components, with special attention to COVID-19 vaccines studies, provides information on the magnitude and causes of adverse events. The understanding of mechanisms involved has made it possible to adequately guide diagnosis, especially to COVID-19 vaccine components, such as polyethylene glycol, trometamol, and polysorbate-80.

Summary

This review focuses on adverse reactions to vaccines, with emphasis on allergic reactions. A diagnostic pathway is suggested that, on the one hand, enables to take the necessary precautions in persons with a history of allergy to vaccine components or allergic reactions to vaccines and, on the other, supports administration of subsequent doses. The overall objective is to ensure that people with allergy can be vaccinated in the same way as the rest of the population, and that they are offered alternatives where necessary.

Citizen Stance towards Mandatory COVID-19 Vaccination and Vaccine Booster Doses: A Study in Colombia, El Salvador and Spain

The infections and deaths resulting from Coronavirus Disease 2019 (COVID-19) triggered the need for some governments to make COVID-19 vaccines mandatory. The present study aims to analyze the position of 3026 adults in Colombia, El Salvador, and Spain regarding the possibility of making COVID-19 vaccine mandatory and the intention to be vaccinated with the booster or possible successive doses. Data from an online survey conducted from August to December 2021 among a non-representative sample of Spanish-speaking countries were collected. Multinomial Logistic Regression Models were used. A total of 77.4% of Colombians were in favor of mandatory vaccination compared to 71.5% of Salvadorians and 65.4% of Spaniards (p < 0.000). Women and people over 65 years of age were the groups most in favor of making the vaccine mandatory (p < 0.000). A total of 79.4% said they had received a third dose or would intend to receive the third dose or future doses, if necessary, compared with 9.4% who expressed doubts and 9.9% who refused to be vaccinated or did not intend to be vaccinated. Among the measures that could be taken to motivate vaccination, 63.0% and 60.6% were in favor of requiring a negative test to enter any place of leisure or work, respectively, compared to 16.2% in favor of suspension from work without pay. The acceptance of mandatory vaccination and of third or future doses varies greatly according to sociodemographic characteristics and work environment. As such, it is recommended that policy makers adapt public health strategies accordingly.

COVID-19 Vaccination Is Safe among Mast Cell Disorder Patients, under Adequate Premedication

Reported cases of anaphylaxis following COVID-19 vaccination raised concerns about the safety of these vaccines, namely in patients suffering from clonal mast cell (MC) disorders-a heterogenous group of disorders in which patients may be prone to anaphylaxis caused by vaccination. This study aimed to assess the safety of COVID-19 vaccines in patients with clonal MC disorders. We performed an ambidirectional cohort study with 30 clonal MC disorder patients (n = 26 in the prospective arm and n = 4 in the retrospective arm), that were submitted to COVID-19 vaccination. Among these, 11 (37%) were males, and median age at vaccination date was 41 years (range: 5y to 76y). One patient had prior history of anaphylaxis following vaccination. Those in the prospective arm received a premedication protocol including H1- and H2-antihistamines and montelukast, while those in the retrospective arm did not premedicate. Overall, patients received a total of 81 doses, 73 under premedication and 8 without premedication. No MC activation symptoms were reported. COVID-19 vaccination seems to be safe in patients with clonal mast cell disorders, including those with prior anaphylaxis following vaccination. Robust premedication protocols may allow for vaccination in ambulatory settings.

Characteristics and Comparison of Adverse Events of Coronavirus Disease 2019 Vaccines Reported to the United States Vaccine Adverse Event Reporting System Between 14 December 2020 and 8 October 2021

Background

This study assessed and compared the frequency and type of adverse events (AEs) of the Pfizer-BioNTech, Moderna, and Janssen coronavirus disease 2019 (COVID-19) vaccines reported in the Vaccine Adverse Event Reporting System (VAERS).

Methods

A retrospective analysis examined VAERS reports between 14 December 2020 and 8 October 2021 and focused on AE reports related to COVID-19 vaccines and AE outcomes [e.g., emergency room (ER) visits after being vaccinated, hospitalization, prolongation of existing hospitalization, life-threatening events, disability, birth defect, and death]. Reporting odds ratios (RORs) and Breslow-Day statistics were used to compare AE reporting between COVID-19 and non-COVID vaccines and between individual COVID-19 vaccines.

Results

A total of 604,157 AEs of COVID-19 vaccines were reported, including 43.51% for the Pfizer-BioNTech vaccine, 47.13% for the Moderna vaccine, and 9.12% for the Janssen COVID-19 vaccine. About 12.56% of patients visited ER after being vaccinated, 5.96% reported hospitalization, and 1.52% reported life-threatening events. Among the number of death cases (n = 7,674; mean age = 73), 2,025 patients (26.39%) had hypertension and 1,237 (16.12%) patients had cancer. RORs between COVID-19 vaccines and non-COVID vaccines identified increased ROR in ER visits, hospitalization, and life-threatening events. The results of the Breslow-Day statistics indicated heterogeneities between the disproportionality of reports across the four serious AE outcomes (i.e., ER visits, hospitalization, life-threatening events, and disability) between individual COVID-19 vaccines.

Conclusion

Most current VAERS reports showed that the most commonly reported AEs of COVID-19 vaccines were mild. Cases with a mortality outcome tended to occur in older adults with underneath conditions. Close ongoing surveillance in the safety of COVID-19 vaccines is critical and will inform the use of individual COVID-19 vaccines. Given the known limitations associated with the passive spontaneous reporting system, such as VAERS, our findings need to be further assessed and verified through longitudinal, large healthcare data systems.

Advances in clinical outcomes: what we have learned during the COVID-19 pandemic

Our understanding of risk factors and interventions influencing outcomes from coronavirus disease 2019 (COVID-19) has continued to evolve, revealing advances emerging from hypotheses formed at the start of the pandemic. Epidemiologic studies have shown that asthma control, rather than a diagnosis of asthma, is a determinant of COVID-19 severity. Clinical outcomes in patients with primary immunodeficiencies, even in those with impaired cellular immunity, are variable. IL-6 has emerged as a reliable biomarker of COVID-19 severity, and large clinical trials have shown the potential for improving outcomes through inhibition of IL-6 signaling in some patients. Studies of genetic risk factors for severe COVID-19 have also revealed the importance of interferon homeostasis in the defense against severe acute respiratory syndrome coronavirus 2. Because COVID-19 vaccines constitute the primary tool for ending this pandemic, strategies have been developed to address potential allergic and immune-mediated reactions. Here, we discuss advances in our understanding of COVID-19 risk factors and outcomes within the context of allergic and immunologic mechanisms.