IgE-mediated systemic reactions to gelatin included in the varicella vaccine

Identifying and Managing Those at Risk for Vaccine-Related Allergy and Anaphylaxis

Immediate hypersensitivity reactions to vaccines, the most severe of which is anaphylaxis, are uncommon events occurring in fewer than 1 in a million doses administered. These reactions are infrequently immunoglobulin E-mediated. Because they are unlikely to recur, a reaction to a single dose of a vaccine is rarely a contraindication to redosing. This narrative review article contextualizes the recent knowledge we have gained from the coronavirus 2019 (COVID-19) pandemic rollout of the new mRNA platform with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines within the much broader context of what is known about immediate reactions to other vaccinations of routine and global importance. We focus on what is known about evidence-based approaches to diagnosis and management and what is new in our understanding of mechanisms of immediate vaccine reactions. Specifically, we review the epidemiology of immediate hypersensitivity vaccine reactions, differential diagnosis for immune-mediated and nonimmune reaction clinical phenotypes, including how to recognize immunization stress-related responses. In addition, we highlight what is known about mechanisms and review the rare but important contribution of excipient allergies and specifically when to consider testing for them as well as other key features that contribute to safe evaluation and management.

Allergic Reactions to Vaccines in Children: From Constituents to Specific Vaccines

Vaccination is an essential public health measure that helps to reduce the burden of infectious diseases in children. Although vaccines have an excellent safety record and the association of severe allergic reactions is rare, public concerns about vaccine safety can lead to incomplete vaccination coverage in children with or without allergies. Therefore, it is important to understand the mechanisms and implications of allergic reactions to vaccines and define strategies to manage them to provide the safest care for vaccine recipients. In this review, we provide an overview on the types of allergic reactions that can occur after vaccination, including those caused by various vaccine constituents. We also discuss the mechanisms underlying these allergic reactions and the recommended diagnosis and management strategies for children with a history of suspected allergic reactions to vaccines. An improved understanding of allergic reactions to vaccines can aid in the enhancement of the safety and effectiveness of vaccination.

The adverse reactions to vaccines practice parameter 10 years on-what have we learned?

Objective

To provide updated information on the evaluation and management of adverse reactions to vaccines.

Data Sources

PubMed (MEDLINE) search since publication of a practice parameter in 2012.

Study Selections

Original articles and guidelines on adverse reactions to vaccines, including vaccines against severe acute respiratory syndrome coronavirus 2 or coronavirus disease 2019 (COVID-19).

Results

Current guidelines conclude that patients with egg allergy are not at increased risk for reaction to egg-based influenza vaccines. Except for gelatin, most patients with allergy to vaccine constituents tolerate vaccines containing them. Most patients who have immediate reactions after receiving COVID-19 vaccines go on to receive a subsequent dose uneventfully.

Conclusion

The risk of reactions to vaccination should be weighed against the risk of having a vaccine-preventable disease if the vaccine is withheld. There is no need to ask about egg allergy before the administration of influenza vaccines, including on screening forms. In most cases, an allergy to a vaccine constituent is not a contraindication to the vaccine containing it. Patients who have had possible anaphylactic reactions to vaccines should be evaluated by an allergist rather than simply being labeled allergic, because most can go on to receive subsequent doses. Most immediate reactions to COVID-19 vaccines are not allergic, and care should be taken to not label such reactions as anaphylactic. The role, if any, of polyethylene glycol in these reactions has yet to be revealed.

Hidden Dangers: Recognizing Excipients as Potential Causes of Drug and Vaccine Hypersensitivity Reactions

Excipients are necessary as a support to the active ingredients in drugs, vaccines, and other products, and they contribute to their stability, preservation, pharmacokinetics, bioavailability, appearance, and acceptability. For both drugs and vaccines, these are rare reactions; however, for vaccines, they are the primary cause of immediate hypersensitivity. Suspicion for these "hidden dangers" should be high, in particular, when anaphylaxis has occurred in association with multiple chemically distinct drugs. Common excipients implicated include gelatin, carboxymethylcellulose, polyethylene glycols, and products related to polyethylene glycols in immediate hypersensitivity reactions and propylene glycol in delayed hypersensitivity reactions. Complete evaluation of a suspected excipient reaction requires detailed information from the product monograph and package insert to identify all ingredients that are present and to understand the function and structure for these chemicals. This knowledge helps develop a management plan that may include allergy testing to identify the implicated component and to give patients detailed information for future avoidance of relevant foods, drugs, and vaccines. Excipient reactions should be particularly considered for specific classes of drugs where they have been commonly found to be the culprit (eg, corticosteroids, injectable hormones, immunotherapies, monoclonal antibodies, and vaccines). We provide a review of the evidence-based literature outlining epidemiology and mechanisms of excipient reactions and provide strategies for heightened recognition and allergy testing.

The science of vaccine safety: Summary of meeting at Wellcome Trust

Vaccines are everywhere hugely successful but are also under attack. The reason for the latter is the perception by some people that vaccines are unsafe. However that may be, vaccine safety, life any other scientific subject, must be constantly studied. It was from this point of view that a meeting was organized at the Wellcome Trust in London in May 2019 to assess some aspects of vaccine safety as subjects for scientific study. The objective of the meeting was to assess what is known beyond reasonable doubt and conversely what areas need additional studies. Although the meeting could not cover all aspects of vaccine safety science, many of the most important issues were addressed by a group of about 30 experts to determine what is already known and what additional studies are merited to assess the safety of the vaccines currently in use. The meeting began with reviews of the current situation in different parts of the world, followed by reviews of specific controversial areas, including the incidence of certain conditions after vaccination and the safety of certain vaccine components. Lastly, information about the human papillomavirus vaccine was considered because its safety has been particularly challenged by vaccine opponents. The following is a summary of the meeting findings. In addition to this summary, the meeting organizers will explore opportunities to perform studies that would enlarge knowledge of vaccine safety.

Immune-mediated adverse reactions to vaccines

Vaccination continues to be the single most important and successful public health intervention, due to its prevention of morbidity and mortality from prevalent infectious diseases. Severe immunologically mediated reactions are rare and less common with the vaccine than the true infection. However, these events can cause public fearfulness and loss of confidence in the safety of vaccination. In this paper, we perform a systematic literature search and narrative review of immune-mediated vaccine adverse events and their known and proposed mechanisms, and outline directions for future research. Improving our knowledge base of severe immunologically mediated vaccine reactions and their management drives better vaccine safety and efficacy outcomes.

Hazardous Medications in Children with Egg, Red Meat, Gelatin, Fish, and Cow's Milk Allergy

Childhood food allergies are a growing public health problem. Once the offending food allergens have been identified, a strict elimination diet is necessary in treatment or prevention of most of the allergic reactions. Accidental food ingestion can lead to severe anaphylaxis. Food- derived substances can be used in medications at various stages of the manufacturing process. In this review, the possible roles of medications which may contain egg, red meat, gelatin, and fish allergens on allergic reactions in children with food allergy were evaluated.

Preventing iatrogenic gelatin anaphylaxis

OBJECTIVE

To assess the iatrogenic risks of gelatin allergy and identify resources for patient management.

DATA SOURCES

A literature review was performed using PubMed and public databases provided by the National Library of Medicine.

STUDY SELECTIONS

Reports of iatrogenic gelatin allergy associated with vaccines, hemostatic agents, intravenous colloids, medicinal capsules, and intraoperative surgical supplies.

RESULTS

Gelatin ingredients may not be identified by electronic medical record safeguards, and an exhaustive listing of potential iatrogenic exposures is elusive. The National Library of Medicine AccessGUDID (https://accessgudid.nlm.nih.gov/) can be a useful resource in evaluating medical devices for gelatin content. Unexpected sources of iatrogenic gelatin exposure include hemostatic agents, vascular grafts, intravascular cannulas, bone replacement implants, and emergency resuscitation fluids.

CONCLUSION

Vigilance is important within medical systems to avoid inadvertent gelatin exposure when caring for patients with gelatin allergy. Additional safeguards are needed to remove latent health care system errors that fail to prevent gelatin administration in this at-risk population.

Adverse reactions to drugs and biologics in patients with clonal mast cell disorders: A Work Group Report of the Mast Cells Disorder Committee, American Academy of Allergy, Asthma & Immunology

Providers caring for patients with mastocytosis are tasked with the decision to consider therapeutic options. This can come with some trepidation because information available in the public domain lists numerous mast cell (MC) activators based on data that do not discriminate between primates, rodents, and MC lines; do not consider dosage; and do not take into account previous exposure and resultant clinical findings. This being said, there is support in the literature for an enhanced MC response in some patients with mastocytosis and in cases in which there is a greater incidence of adverse reactions associated with certain antigens, such as venoms and drugs. Thus this report provides a comprehensive guide for those providers who must decide on therapeutic options in the management of patients with clonal MC disease.

Safety of Second-Dose Single-Antigen Varicella Vaccine

BACKGROUND AND OBJECTIVE

In 2006, routine 2-dose varicella vaccination for children was recommended to improve control of varicella. We assessed the safety of second-dose varicella vaccination.

METHODS

We identified second-dose single-antigen varicella vaccine reports in the Vaccine Adverse Event Reporting System during 2006 to 2014 among children aged 4 to 18 years. We analyzed reports by age group (4-6 and 7-18 years), sex, serious or nonserious status, most common adverse events (AEs), and whether other vaccines were administered concomitantly with varicella vaccine. We reviewed serious reports of selected AEs and conducted empirical Bayesian data mining to detect disproportional reporting of AEs.

RESULTS

We identified 14 641 Vaccine Adverse Event Reporting System reports after second-dose varicella vaccination, with 494 (3%) classified as serious. Among nonserious reports, injection site reactions were most common (48% of children aged 4-6 years, 38% of children aged 7-18 years). The most common AEs among serious reports were pyrexia (31%) for children aged 4 to 6 years and headache (28%) and vomiting (27%) for children aged 7 to 18 years. Serious reports of selected AEs included anaphylaxis (83), meningitis (5), encephalitis (16), cellulitis (52), varicella (6), herpes zoster (6), and deaths (7). One immunosuppressed adolescent was reported with vaccine-strain herpes zoster. Only previously known AEs were reported more frequently after second-dose varicella vaccination compared with other vaccines.

CONCLUSIONS

We identified no new or unexpected safety concerns for second-dose varicella vaccination. Robust safety monitoring remains an important component of the national varicella vaccination program.

Sensitization to bovine serum albumin as a possible cause of allergic reactions to vaccines

BACKGROUND

Immediate type hypersensitivity to vaccines containing bovine/porcine excipients, such as the measles, mumps and rubella (MMR) vaccine is probably due to sensitization to bovine/porcine gelatin. Most patients with such reactions in Sri Lanka have cow's milk (CM) or beef allergy.

OBJECTIVES

We investigated whether those who had beef and CM allergy had a higher incidence of hypersensitivity reactions to vaccines and the possible trigger of such reactions.

MATERIAL AND METHODS

Twenty patients with immediate type hypersensitivity reactions to vaccines containing bovine/porcine excipients, controls with allergy to beef/pork (n=11) or CM (n=11), and 8 non atopic controls were recruited. Total serum IgE, specific IgE to beef, CM, casein, beta lactoglobulin, gelatin and bovine serum albumin (BSA) by Phadia ImmunoCap and IgE to porcine gelatin by Western blot were evaluated.

RESULTS

11/20, 5/20, 2/20, 2/20, 1/20 and 1/20 patients reported allergic reactions to measles containing, JE, rabies primary chick embryo, pentavalent, diphtheria and tetanus, and adult diphtheria and tetanus vaccines, respectively. Only one patient with allergy to vaccines had gelatin specific IgE, whereas IgE to BSA was seen in 73.3%, 90%, 66.6% and 0 of vaccine, beef or CM allergic and non-atopic controls, respectively. The mean IgE to BSA was higher in patients with allergy to vaccines, although not significant. Specific IgE to BSA was present in 54.7% of children with allergy to CM, of whom 11.8% had high levels (>17.5kUA/L). In contrast, 66.6% of these children did not have specific IgE to β-lactoglobulin, which is one of the major components of whey protein.

CONCLUSION AND CLINICAL RELEVANCE

Gelatin does not appear to play a major role in Sri Lankan children with allergy to vaccines. In contrast, due to the higher levels of BSA specific IgE, sensitization to BSA is possibly playing a role.

International Consensus (ICON): allergic reactions to vaccines

BACKGROUND

Routine immunization, one of the most effective public health interventions, has effectively reduced death and morbidity due to a variety of infectious diseases. However, allergic reactions to vaccines occur very rarely and can be life threatening. Given the large numbers of vaccines administered worldwide, there is a need for an international consensus regarding the evaluation and management of allergic reactions to vaccines.

METHODS

Following a review of the literature, and with the active participation of representatives from the World Allergy Organization (WAO), the European Academy of Allergy and Clinical Immunology (EAACI), the American Academy of Allergy, Asthma, and Immunology (AAAAI), and the American College of Allergy, Asthma, and Immunology (ACAAI), the final committee was formed with the purpose of having members who represented a wide-range of countries, had previously worked on vaccine safety, and included both allergist/immunologists as well as vaccinologists.

RESULTS

Consensus was reached on a variety of topics, including: definition of immediate allergic reactions, including anaphylaxis, approaches to distinguish association from causality, approaches to patients with a history of an allergic reaction to a previous vaccine, and approaches to patients with a history of an allergic reaction to components of vaccines.

CONCLUSIONS

This document provides comprehensive and internationally accepted guidelines and access to on-line documents to help practitioners around the world identify allergic reactions following immunization. It also provides a framework for the evaluation and further management of patients who present either following an allergic reaction to a vaccine or with a history of allergy to a component of vaccines.

Vaccine allergy

Overdiagnosis of vaccine allergy is considered a major public health problem. This article discusses the different types of allergic reactions after immunization based on the timing (immediate vs nonimmediate) and the extent of the reaction (local vs systemic). The vaccine components potentially responsible for an allergic reaction are discussed, as well as the management of patients with a history of reaction to a specific vaccine and those with a history of allergy to one of the vaccine components.

Vaccination in children with allergy to non active vaccine components

Childhood immunisation is one of the greatest public health successes of the last century. Vaccines contain an active component (the antigen) which induces the immune response. They may also contain additional components such as preservatives, additives, adjuvants and traces of other substances. This review provides information about risks of hypersensitivity reactions to components of vaccines. Furthermore, recommendations to avoid or reduce reactions to vaccine components have been detailed.

Potential food allergens in medications

Excipients are substances in pharmaceuticals other than the active ingredients. Some excipients are foods or substances derived from foods, raising the possibility that these substances would pose a hazard to patients with food allergy. This review describes which food-derived substances are used as pharmaceutical excipients in which medications and reviews published data regarding the safety of the administration of these medications to recipients with food allergy. Such reactions are rare, usually because the amount of food protein is not present in a large enough quantity to elicit a reaction. When a food protein appears as an unintentional contaminant, the amount, if any, that is present might be variable and might elicit reactions only from some lots of medication or only in some patients. In most circumstances these medications should not be routinely withheld from patients who have particular food allergies because most will tolerate the medications uneventfully. However, if a particular patient has had an apparent allergic reaction to the medication, potential allergy to the food component should be investigated.

Allergic reactions to vaccines

Anaphylactic reactions to vaccines are rare but do occur, and have been reported for nearly every vaccine. And while the reaction rate per each dose of vaccine is low, this is a common clinical question due in large part to the enormous numbers of vaccines administered. Reactions are most often due to vaccine constituents rather than the microbial components of the vaccine, but in many instances, the specific ingredient triggering the reaction cannot be definitively identified. Evaluation of patients with suspected vaccine reactions should begin by determining whether the symptoms and timing of the reaction were consistent with a true allergic reaction, followed by an assessment to determine whether the patient needs further doses of the vaccine in question, or similar vaccines, in the future. Skin and serologic testing to vaccines and vaccine constituents can then be performed to further assess the potential cause of the reaction and to develop a plan for future immunizations. Specific guidelines for the administration of influenza vaccines to egg allergic patients have been revised to allow virtually all patients to receive this vaccine in a straightforward manner.

Review of the United States universal varicella vaccination program: Herpes zoster incidence rates, cost-effectiveness, and vaccine efficacy based primarily on the Antelope Valley Varicella Active Surveillance Project data

In a cooperative agreement starting January 1995, prior to the FDA's licensure of the varicella vaccine on March 17, the Centers for Disease Control and Prevention (CDC) funded the Los Angeles Department of Health Services' Antelope Valley Varicella Active Surveillance Project (AV-VASP). Since only varicella case reports were gathered, baseline incidence data for herpes zoster (HZ) or shingles was lacking. Varicella case reports decreased 72%, from 2834 in 1995 to 836 in 2000 at which time approximately 50% of children under 10 years of age had been vaccinated. Starting in 2000, HZ surveillance was added to the project. By 2002, notable increases in HZ incidence rates were reported among both children and adults with a prior history of natural varicella. However, CDC authorities still claimed that no increase in HZ had occurred in any US surveillance site. The basic assumptions inherent to the varicella cost-benefit analysis ignored the significance of exogenous boosting caused by those shedding wild-type VZV. Also ignored was the morbidity associated with even rare serious events following varicella vaccination as well as the morbidity from increasing cases of HZ among adults. Vaccine efficacy declined below 80% in 2001. By 2006, because 20% of vaccinees were experiencing breakthrough varicella and vaccine-induced protection was waning, the CDC recommended a booster dose for children and, in 2007, a shingles vaccination was approved for adults aged 60 years and older. In the prelicensure era, 95% of adults experienced natural chickenpox (usually as children)-these cases were usually benign and resulted in long-term immunity. Varicella vaccination is less effective than the natural immunity that existed in prevaccine communities. Universal varicella vaccination has not proven to be cost-effective as increased HZ morbidity has disproportionately offset cost savings associated with reductions in varicella disease. Universal varicella vaccination has failed to provide long-term protection from VZV disease.

Update on vaccination guidelines for allergic children

Children with allergic or atopic diseases require immunization just like non-atopic children. However, vaccination of such children requires some special considerations and precautions. Children may be allergic to specific vaccine constituents such as gelatin or egg. Children who have suffered an apparent allergic reaction to a vaccine should be evaluated by an allergist to determine the culprit allergen and to make recommendations regarding future vaccination. In rare circumstances, certain vaccines may cause acute exacerbations of allergic diseases, but the contention that vaccination causes allergic disease is not substantiated by any available evidence.

A reliable enzyme linked immunosorbent assay for the determination of bovine and porcine gelatin in processed foods

Since gelatin-containing foods pose a risk for eliciting allergic reactions in sensitized individuals, a novel sandwich enzyme linked-immunosorbent assay (ELISA) for the detection and quantification of bovine and porcine gelatin in processed foods was developed. Rabbits and goats were immunized with bovine gelatin, and three antisera (pAb1 and pAb2 from rabbits, and pAb3 from goats) were obtained. We established a sandwich ELISA method based on a combination of these antibodies. In this study, two sandwich ELISA methods, rabbit pAb2-pAb1 and goat pAb3-pAb3, were evaluated for sensitivity, specificity, cross-reactivity, and applicability. Both ELISA methods were highly specific for bovine and porcine gelatin but had little reactivity with fish gelatin. The detection and quantification limits for porcine gelatin were found to be 0.78 ng/mL and 1.56 ng/mL, respectively. The established sandwich ELISA methods produced no false-positives, except for heated meat products or false negatives when various commercial foods were analyzed for their gelatin content. The rabbit pAb2-pAb1 ELISA cross-reacted with boiled squid, while the goat pAb3-pAb3 ELISA did not. Thus, the proposed goat pAb3-pAb3 ELISA method is a reliable tool for the detection of gelatin contaminants present in processed foods.

An algorithm for treatment of patients with hypersensitivity reactions after vaccines

Concerns about possible allergic reactions to immunizations are raised frequently by both patients/parents and primary care providers. Estimates of true allergic, or immediate hypersensitivity, reactions to routine vaccines range from 1 per 50000 doses for diphtheria-tetanus-pertussis to approximately 1 per 500000 to 1000000 doses for most other vaccines. In a large study from New Zealand, data were collected during a 5-year period on 15 marketed vaccines and revealed an estimated rate of 1 immediate hypersensitivity reaction per 450000 doses of vaccine administered. Another large study, conducted within the Vaccine Safety Datalink, described a range of reaction rates to >7.5 million doses. Depending on the study design and the time after the immunization event, reaction rates varied from 0.65 cases per million doses to 1.53 cases per million doses when additional allergy codes were included. For some vaccines, particularly when allergens such as gelatin are part of the formulation (eg, Japanese encephalitis), higher rates of serious allergic reactions may occur. Although these per-dose estimates suggest that true hypersensitivity reactions are quite rare, the large number of doses that are administered, especially for the commonly used vaccines, makes this a relatively common clinical problem. In this review, we present background information on vaccine hypersensitivity, followed by a detailed algorithm that provides a rational and organized approach for the evaluation and treatment of patients with suspected hypersensitivity. We then include 3 cases of suspected allergic reactions to vaccines that have been referred to the Clinical Immunization Safety Assessment network to demonstrate the practical application of the algorithm.

The case against universal varicella vaccination

In 1995, the United States became the first country to implement a Universal Varicella Vaccination Program. Several questions remain: Is the varicella (chickenpox) vaccine needed? Is it cost effective as a routine immunization for all susceptible children? Or is it more beneficial for the disease to remain endemic so that adults may receive periodic exogenous exposures (boosts) that help suppress the reactivation of herpes zoster (shingles). In addition, as vaccination coverage becomes widespread, does loss of immunologic boosting cause a decline in vaccine efficacy and result in a reduced period of immunity? Scientific literature regarding safety of the varicella vaccine and its associated cost-benefit analysis have often reported optimistic evaluations based on ideal assumptions. Deleterious outcomes and their associated costs must be included when making a circumspect assessment of the Universal Varicella Vaccination Program.

Safety and immunogenicity of gelatin-free varicella vaccine in epidemiological and serological studies in Japan

Following gelatin-containing varicella vaccine (1994-1999: 1,410,000 distributed doses), 28 serious anaphylactic reactions and 139 non-serious allergic reactions were reported, with no serious and only five non-serious reactions following gelatin-free vaccine (1999-2000: 1,300,000 distributed doses). All nine sera available from children with serious reactions tested positive for gelatin-specific IgE, whereas 55 of the 70 available from those with non-serious reactions were positive, with one false positive. There was no correlation between gelatin-specific IgE antibody titers and severity of allergic reaction. Post-immunization anti-varicella antibody titers were comparable for both gelatin-free and gelatin-containing vaccine groups. The new gelatin-free varicella vaccine is thought to be safe, with similar immunogenicity to the earlier gelatin-containing vaccine.

Addressing parents' concerns: do vaccines contain harmful preservatives, adjuvants, additives, or residuals?

Vaccines often contain preservatives, adjuvants, additives, or manufacturing residuals in addition to pathogen-specific immunogens. Some parents, alerted by stories in the news media or information contained on the World Wide Web, are concerned that some of the substances contained in vaccines might harm their children. We reviewed data on thimerosal, aluminum, gelatin, human serum albumin, formaldehyde, antibiotics, egg proteins, and yeast proteins. Both gelatin and egg proteins are contained in vaccines in quantities sufficient to induce rare instances of severe, immediate-type hypersensitivity reactions. However, quantities of mercury, aluminum, formaldehyde, human serum albumin, antibiotics, and yeast proteins in vaccines have not been found to be harmful in humans or experimental animals.

Vaccine allergy: diagnosis and management

As a group, vaccines provide a safe and effective way of preventing infectious and allergic illness. Allergic reactions to vaccines and drug products have become important and common features of practice and demand heightened awareness. Serious adverse effects of vaccines are rare but have been reported to various components of different vaccines. Although there are few precise diagnostic tests available, patients usually can be diagnosed accurately after careful attention to the history and physical findings. Better understanding of these reactions can lead to proper vaccine selection and can improve immunization acceptance rates in the community. Prevention, avoidance, use of alternative agents, desensitization, and premedication remain the mainstays of therapy, even as more refined diagnostic and management tools are developed. VAERS data, in addition to the traditional uses (signal detection, large registry of rare vaccine adverse events), can serve as a source of cases for epidemiologic (eg, case-control) studies that evaluate biologic factors that may be related to vaccine-related adverse reactions. Additional studies that are aimed at identifying other causes of immediate hypersensitivity after immunization with live virus vaccines are warranted.

Immunization of egg-allergic individuals with egg- or chicken-derived vaccines

Viruses used in several vaccines are propagated in embryonated eggs. These vaccines contain variable quantities of residual egg or chicken proteins and pose risks when administered to egg- or chicken-sensitive persons. This article highlights differences in how vaccines are prepared, with emphasis on the quantitation of residual egg-derived protein in each vaccine. Published reports on the frequency and severity of these vaccine-induced allergic reactions are reviewed, and an algorithm is provided for the preimmunization evaluation of egg-sensitive persons.

Adverse reactions to vaccines

(The opinions or assertions contained herein are the private views of the authors and are not to be construed as official or as reflecting the views of the Department of the Army or the Department of Defense.) Immunization healthcare is becoming increasingly complex as the number and types of vaccines have continued to expand. Like all prescription drugs, vaccines may be associated with adverse events. The majority of these reactions are self-limited and not associated with prolonged disability. The media, Internet and public advocacy groups have focused on potentially serious vaccine-associated adverse events with questions raised about causal linkages to increasing frequencies of diseases such as autism and asthma. Despite a lack of evidence of a causal relationship to a variety of vaccine safety concerns, including extensive reviews by the Institute of Medicine, questions regarding vaccine safety continue to threaten the success of immunization programs. Risk communication arid individual risk assessment is further challenged by the public health success of vaccine programs creating the perception that certain vaccines are no longer necessary or justified because of the rare reaction risk. There is a need for improved understanding of true vaccine contraindications and precautions as well as host factors and disease threat in order to develop a patient specific balanced risk communication intervention. When they occur, vaccine related adverse events must be treated, documented and reported through the VAERS system. The increasing complexity of vaccination health care has led the Center of Disease Control and Prevention (CDC) to identify Vaccine Safety Assessment and Evaluation as a potential new specialty.

Prevalence of anti-gelatin IgE antibodies in people with anaphylaxis after measles-mumps rubella vaccine in the United States

OBJECTIVE

Anaphylaxis after immunization, although rare, is serious and potentially life-threatening. Understanding risk factors for this reaction is therefore important. Gelatin is added to many vaccines as a heat stabilizer. Japanese researchers have demonstrated a strong association between immediate hypersensitivity reactions to measles, mumps, rubella, varicella, and Japanese encephalitis immunizations and subsequent detection of anti-gelatin immunoglobulin E (IgE) antibodies. They suggested that previous receipt by these patients of diphtheria-tetanus-acellular pertussis vaccines with trace amounts of gelatin was responsible for the sensitization. We aimed to assess whether a similar association exists for vaccinees in the United States who reported anaphylaxis after receipt of measles-mumps-rubella (MMR) or measles vaccines and to review recent trends in reporting of hypersensitivity reactions.

METHODS

We conducted a retrospective case-control study. Cases of anaphylaxis that met a predefined case definition were identified from the US Vaccine Adverse Event Reporting System (VAERS). Mayo Clinic patients who received MMR vaccine uneventfully served as controls. The study subjects were interviewed to obtain the history of allergies. Sera from study subjects and their matched controls were tested for IgE antibodies to gelatin, whole egg, and vaccine viral antigens using solid-phase radioimmunoassay. Data from the Biologics Surveillance System on annual numbers of doses of MMR and varicella vaccines distributed in the United States were used to evaluate possible changes in reporting of selected allergic adverse events.

RESULTS

Fifty-seven study subjects were recruited into the study and interviewed. Of these, 22 provided serum samples for IgE testing. Twenty-seven subjects served as a comparison group and provided a sample for IgE testing; 21 of these completed an allergy history questionnaire. Self-reported history of food allergies was present more frequently in the interviewed study subjects than in the controls, whereas the proportions of people with other characteristics were similar in both groups. None of the interviewed people had a history of food allergy to gelatin. The level of anti-gelatin IgE antibodies was significantly higher among study subjects than among controls, whereas the levels of IgE antibodies against egg and all 3 viral antigens did not differ significantly. Of 22 study subjects, 6 (27%) tested positive for anti-gelatin IgE, whereas none of the 27 controls did. The rate of anaphylactic reactions reported to VAERS after measles virus-containing immunization in the United States between 1991 and 1997 is 1.8 per 1 million doses distributed. No substantial increase in the number of reported allergic events after frequently used gelatin containing MMR and varicella vaccines could be observed during the first 4 years (1997-2000) since the introduction of diphtheria-tetanus-acellular pertussis vaccines for use in infancy.

CONCLUSION

Anaphylactic reactions to MMR in the United States are rare. The reporting rate has the same order of magnitude as estimates from other countries. Almost one fourth of patients with reported anaphylaxis after MMR seem to have hypersensitivity to gelatin in the vaccine. They may be at higher risk of developing anaphylaxis to subsequent doses of other gelatin-containing vaccines. These people should seek an allergy evaluation before such immunization.

Analysis of HLA in children with gelatin allergy

Systemic immediate reactions including anaphylaxis to gelatin in vaccines have been reported. However, the number of such reports is very small compared with the number of children exposed to gelatin. The present study was designed to investigate whether susceptibility or resistance to gelatin allergy is associated with human leukocyte antigen (HLA) class II gene. Blood samples were obtained from 49 patients with gelatin allergy and specific IgE to gelatin. DNA-based HLA class II typing was performed to determine the DRB1, DQB1 and DPB1 alleles. Genotype frequencies were compared with those found in 240 unrelated controls. The frequency of DQB1*0303 (55.1%) was significantly higher in the patients than in the control subjects (32.1%). The frequency of DPB1*0402 was also significantly higher in the patients (32.7%) than in the control subjects (15.4%). On the other hand, the frequency of subjects carrying DRB1*15 (DRB1*1501 and DRB1*1502) was significantly lower among the patients group (18.4%) than among the controls (40.8%). We found that DQB1*0303 and DPB1*0402 were positively associated with the IgE response for gelatin, while DRB1*15 was negatively associated with it.

Specific IgE and IgG to gelatin in children with systemic cutaneous reactions to Japanese encephalitis vaccines

BACKGROUND

Systemic allergic reactions to Japanese encephalitis (JE) vaccine that include urticaria, angioedema, and rash have been reported. In Japan, children who suffered from allergic immediate-type reactions to JE vaccine had antigelatin IgE in their sera. However, the immunologic mechanism of allergic nonimmediate-type reactions that consist of cutaneous signs appearing several hours or more after JE vaccination has not been defined.

METHODS

Serum samples were taken from 28 children who showed allergic nonimmediate-type cutaneous reactions to JE vaccine. Furthermore, serum samples were taken from 10 children who showed allergic immediate-type reactions with cutaneous signs and/or respiratory symptoms to JE vaccine. We have defined an immediate-type reaction as one occurring within 1 h after vaccination.

RESULTS

Of 10 children who showed immediate-type reactions, all had antigelatin IgE and IgG. Of 28 children who showed systemic nonimmediate-type reactions, one had antigelatin IgE and nine (32%) had antigelatin IgG. The child who had antigelatin IgE showed urticaria 2 h after JE vaccination.

CONCLUSION

These results suggest that some children who showed allergic nonimmediate-type reactions to JE vaccine were sensitized to gelatin.

Allergic reactions to measles-mumps-rubella vaccination

OBJECTIVE

Immunization of egg-allergic children against measles, mumps, and rubella (MMR) is often deferred or even denied, although the safety of this vaccination has been clearly shown. Moreover, the majority of severe allergic reactions have occurred in egg-tolerant vaccinees. Other allergenic vaccine components have been sought, and gelatin has been suggested as one cause of allergic adverse events. The aim of this study was to further characterize the actual allergenic vaccine components.

METHODS

Serum samples from 36 recipients of MMR vaccine with anaphylaxis, urticaria with or without angioedema, asthmatic symptoms, or Henoch-Schönlein purpura were analyzed by CAP System radioallergosorbent test (RAST) and immunospot methods to detect the allergenic vaccine component. To evaluate the correspondence between the findings in the CAP System RAST or the immunospot and clinical symptoms, histories of allergies and present hypersensitivity symptoms were assessed.

RESULTS

Of the 36 participants, 10 were demonstrated to be allergic to gelatin. Seven of them had persistent allergic symptoms, possibly attributable to foods containing gelatin or cross-reactive allergens. The results of the immunospot suggested concomitant allergy to gelatin and egg, chicken, and feathers, as well as cow's milk, or they reflected allergen cross-reactivity.

CONCLUSIONS

Although severe allergic adverse events attributable to MMR vaccination are extremely rare, all serious allergic reactions should be further assessed to detect the likely causative vaccine component, including gelatin. The current recommendation for immunization of egg-allergic persons according to standard MMR vaccination schedules is reinforced. measles, mumps, and rubella vaccine, immunization, adverse effects, allergic reactions, gelatin allergy, CAP System, radioallergosorbent test, immunospot, immunoglobulin E.

The lymphoproliferative response to enzymatically digested gelatin in subjects with gelatin hypersensitivity

BACKGROUND

This study was designed to evaluate the immunogenic characteristics of enzymatically digested gelatin, 'FreAlagin', employing the lymphoproliferative response in subjects with gelatin hypersensitivity. Our purpose was to assess the response of primed lymphocytes to the newly developed FreAlagin and compare it to the response to conventional gelatin.

METHODS

A gelatin-specific lymphocyte proliferation test (LPT) was performed in 110 children with adverse reactions to gelatin-containing vaccines, who showed positive gelatin-specific cell-mediated immunity and were thus diagnosed as having gelatin hypersensitivity. Gelatin-specific IgE was measured in all subjects. The antigenic activity of FreAlagin to lymphocytes was compared with that of conventional bovine gelatin. Positive and negative control specimens were obtained from the patients with anaphylaxis and from subjects inoculated with gelatin-free vaccine who showed no adverse reactions in order to establish the fluorometric ELISA system to determine IgE antibody to gelatin and LPT.

RESULTS

The lymphocyte activity against FreAlagin was much less than that to Wako gelatin and more than half of the subjects who reacted positively to Wako gelatin had a negative LPT to FreAlagin. Although 47% of the subjects had positive LPTs to FreAlagin, all but two still had lower SIs to FreAlagin compared with Wako gelatin.

CONCLUSION

We conclude that the antigenic activity of FreAlagin as measured by the cell-mediated immune response is significantly less than that of conventional bovine gelatin. However, it is still necessary to perform clinical trials to show a reduced or absent clinical reactivity to FreAlagin in sensitized patients to conventional gelatin.

IgE sensitization to gelatin: the probable role of gelatin-containing diphtheria-tetanus-acellular pertussis (DTaP) vaccines

We recently found that most events of anaphylaxis to live attenuated viral vaccines containing gelatin as a stabilizer might be caused by the gelatin. However, the mechanism that the children were sensitized to gelatin was unclear. In Japan, both diphtheria-tetanus-acellular pertussis (DTaP) vaccines with and without gelatin are available. We explored the possibility that gelatin-containing DTaP vaccines before live viral vaccines sensitize children to gelatin. We received the serum samples of 87 children who had systemic immediate-type reactions including anaphylaxis to the vaccines from both physicians and vaccine manufacturers throughout Japan. We then surveyed the DTaP vaccination histories of the children who demonstrated anti-gelatin IgE. Of the above 87 children, 79 (91%) had anti-gelatin IgE. We successfully collected DTaP vaccination histories including the manufacturers' names and numbers of doses on 55 children. Only one child had not received any DTaP vaccine, the other 54 had received gelatin-containing DTaP vaccines and none received gelatin-free DTaP vaccines. We concluded that there was a strong causal relationship between gelatin-containing DTaP vaccination, anti-gelatin IgE production, and risk of anaphylaxis following subsequent immunization with live viral vaccines which contain a larger amount of gelatin.

Sensitization to gelatin in children with systemic non-immediate-type reactions to varicella vaccines

BACKGROUND

We recently found that four children who experienced systemic immediate-type reactions to varicella vaccine with gelatin had anti-gelatin IgE. We also found systemic non-immediate-type allergic reactions, which mainly consist of systemic cutaneous signs, appearing several hours or more after the vaccination.

OBJECTIVE

To investigate the relationship between immune responses to gelatin and non-immediate-type reactions to gelatin-containing varicella vaccines, we measured anti-gelatin IgE and IgG in the sera of the children with these allergic reactions.

METHODS

Serum samples were taken from 21 children who showed non-immediate-type reactions to varicella vaccines. As a positive control, serum samples were taken from 33 children who showed immediate-type reactions to varicella vaccine and had anti-gelatin IgE. As a negative control, serum samples were taken from 50 children who showed no reaction to the vaccine. We then examined anti-gelatin IgE and IgG in sera of the children.

RESULTS

Of 21 children with non-immediate-type reactions, two (10%) had anti-gelatin IgE and six (29%) had anti-gelatin IgG. In the positive control group, all 33 children with immediate-type reactions had anti-gelatin IgG as well as IgE. In the negative control group, all 50 children who showed no allergic reaction to varicella vaccines had neither anti-gelatin IgE nor IgG.

CONCLUSIONS

These results suggest that the possibility exists that some non-immediate-type reactions to varicella vaccine are caused by immune reactions to gelatin.

Gelatin-containing diphtheria-tetanus-pertussis (DTP) vaccine causes sensitization to gelatin in the recipients

Gelatin-specific T cell response was performed to determine whether a series of vaccinations with gelatin-containing DTP is a primary sensitization process in gelatin allergy. Thirty-seven recipients with gelatin-containing DTP who developed adverse reactions after vaccination and eight recipients of DTP without gelatin who also developed adverse reactions were studied. In addition, 10 subjects receiving gelatin-containing vaccine and 10 subjects inoculated with non-gelatin vaccine who did not show any adverse reactions were also investigated. All subjects inoculated with gelatin-containing DTP vaccine showed positive T cell responses against gelatin, however, occurrence of adverse reactions did not correlate with T cell responses. We conclude that DTP vaccine containing gelatin induces sensitization to gelatin in the recipients, but the mechanism of local reactions remains unknown.

IgE reactivity to alpha1 and alpha2 chains of bovine type 1 collagen in children with bovine gelatin allergy

BACKGROUND

Anaphylactic reactions to measles, mumps, and rubella vaccines, including gelatin as a stabilizer, have been reported. It had been found that most of these reactions to live vaccines are caused by the bovine gelatin included in these vaccines. Gelatin mainly includes denatured type I collagen, which consists of alpha1 and alpha2 chains.

OBJECTIVE

The current study was designed to investigate the IgE reactivity to alpha1 and alpha2 chains of bovine type I collagen in gelatin-sensitive children.

METHODS

Serum samples were taken from 10 children who had anaphylaxis to the vaccines and high levels of specific IgE to bovine gelatin. Bovine type I collagen was isolated from bovine skin and then separated to alpha1 and alpha2 chains by column chromatography. IgE reactivity to denatured type I collagen and its alpha1 and alpha2 chains was analyzed by immunoblotting, ELISA, and histamine release from the mast cells passive sensitized with IgE antibodies in pooled serum of the children.

RESULTS

All children had specific IgE to bovine type I collagen. Furthermore, IgE antibodies in their sera reacted with the alpha;2 chain but not with the alpha1 chain. Similarly, the mast cells sensitized with pooled sera in the children showed alpha2 chain-specific histamine release but not alpha1 chain-specific histamine release.

CONCLUSION

In gelatin allergy denatured bovine type I collagen is a major allergen and IgE-binding sites exist in the alpha2 chain of type I collagen.