The impact of COVID-19 vaccine reactions on secondary vaccine hesitancy.

BACKGROUND: Primary and booster vaccinations are critical for mitigating COVID-19 transmission, morbidity, and mortality. Future booster vaccine campaigns rely on an increased understanding of vaccine hesitancy. OBJECTIVE: To evaluate self-reported allergic and skin vaccine reactions as factors potentially associated with vaccine hesitancy in a nationwide vaccine allergy registry. METHODS: Responses to survey questions concerning COVID-19 vaccine perceptions, coded from free text by 2 independent reviewers. Multivariable logistic regression models were used to determine the association between changed negative perception and respondent demographics, vaccination history, and reaction characteristics. RESULTS: A total of 993 individuals (median of 46 years [IQR, 36-59], 88% female, 82% White) self-reported reactions to COVID-19 vaccination. Reactions included the following: delayed large local skin reaction (40%), hives/urticaria (32%), immediate large local skin reaction (3%), swelling (3%), anaphylaxis (2%), and other or unspecified (20%). Most respondents were initially unconcerned about the safety of COVID-19 vaccines (56%). After reactions, 401 of 993 (40%) report negative change in perception of vaccination, with more than half of these respondents (n = 211, 53%) citing their reasoning as a negative experience with adverse effects. Of 102 individuals asked about future vaccination, 79 (77%) indicated that they were unlikely or very unlikely to receive future COVID-19 vaccinations. Increased negative perception after reaction was associated with younger age, later COVID-19 vaccination dose number, and reaction type. CONCLUSION: Our findings reveal that an individual's experience with allergic or cutaneous adverse effects after COVID-19 vaccination affects attitudes and decision-making regarding future vaccination, even in initially non-hesitant individuals. Further investigation of secondary vaccine hesitancy is necessary for adapting public health messaging to this important population.

A systematic review and expert Delphi Consensus recommendation on the use of vaccines in patients receiving dupilumab: A position paper of the American College of Allergy, Asthma and Immunology.

BACKGROUND: Dupilumab is a monoclonal antibody that targets the interleukin (IL)-4 receptor alpha subunit, thus blocking the effects of IL-4 and IL-13, and has shown efficacy in treating various conditions including asthma, atopic dermatitis, eosinophilic esophagitis, and others. Because of its immune modulatory effects, clinical trials that studied dupilumab did not allow patients to receive live vaccines during the clinical trials because of an abundance of caution, and thus package inserts recommend that patients who are being treated with dupilumab should avoid live vaccines. Because dupilumab is now approved for use in patients from 6 months of age for the treatment of atopic dermatitis, this reported contraindication is now posing a clinical dilemma for patients and clinicians. OBJECTIVE: To perform a systematic review of literature on the safety and efficacy of vaccinations in patients who are receiving dupilumab and to provide expert guidance on the use of vaccines in patients who are receiving dupilumab. METHODS: A systematic review of the literature was performed, and an expert Delphi Panel was assembled. RESULTS: The available literature on patients who received vaccinations while using dupilumab overall suggests that live vaccines are safe and that the vaccine efficacy, in general, is not affected by dupilumab. The expert Delphi panel agreed that the use of vaccines in patients receiving dupilumab was likely safe and effective. CONCLUSION: Vaccines (including live vaccines) can be administered to patients receiving dupilumab in a shared decision-making capacity.

United States Drug Allergy Registry (USDAR) grading scale for immediate drug reactions.

BACKGROUND: There is no accepted grading system classifying the severity of immediate reactions to drugs. OBJECTIVE: The purpose of this article is to present a proposed grading system developed through the consensus of drug allergy experts from the United States Drug Allergy Registry (USDAR) Consortium. METHODS: The USDAR investigators sought to develop a consensus severity grading system for immediate drug reactions that is applicable to clinical care and research. RESULTS: The USDAR grading scale scores severity levels on a scale of 0 to 4. A grade of no reaction (NR) is used for patients who undergo challenge without any symptoms or signs, and it would confirm a negative challenge result. A grade 0 reaction is indicative of primarily subjective complaints that are commonly seen with both historical drug reactions and during drug challenges, and it would suggest a low likelihood of a true drug allergic reaction. Grades 1 to 4 meet the criteria for a positive challenge result and may be considered indicative of a drug allergy. Grade 1 reactions are suggestive of a potential immediate drug reaction with mild symptoms. Grade 2 reactions are more likely to be immediate drug reactions of moderate severity. Grade 3 reactions have features suggestive of a severe allergic reaction, whereas grade 4 reactions are life-threatening reactions such as anaphylactic shock and fatal anaphylaxis. CONCLUSION: This proposed grading schema for immediate drug reactions improves on prior schemata by being developed specifically for immediate drug reactions and being easy to implement in clinical and research practice.

Diagnostic accuracy of vaccine and vaccine excipient testing in the setting of allergic reactions to COVID-19 vaccines: A systematic review and meta-analysis.

For persons with immediate allergic reactions to mRNA COVID-19 vaccines, skin testing (ST) to the vaccine/excipients (polyethylene glycol[PEG] and polysorbate 80 [PS]) has been recommended, but has unknown accuracy. To assess vaccine/excipient ST accuracy in predicting all-severity immediate allergic reactions upon re-vaccination, systematic review was performed searching Medline, EMBASE, Web of Science, and the WHO global coronavirus database (inception-Oct 4, 2021) for studies addressing immediate (≤4 h post-vaccination) all-severity allergic reactions to 2nd mRNA COVID-19 vaccination in persons with 1st dose immediate allergic reactions. Cases evaluating delayed reactions, change of vaccine platform, or revaccination without vaccine/excipient ST were excluded. Meta-analysis of diagnostic testing accuracy was performed using Bayesian methods. The GRADE approach evaluated certainty of the evidence, and QUADAS-2 assessed risk of bias. Among 20 studies of mRNA COVID-19 first dose vaccine reactions, 317 individuals underwent 578 ST to any one or combination of vaccine, PEG, or PS, and were re-vaccinated with the same vaccine. Test sensitivity for either mRNA vaccine was 0.2 (95%CrI 0.01-0.52) and specificity 0.97 (95%CrI 0.9-1). PEG test sensitivity was 0.02 (95%CrI 0.00-0.07) and specificity 0.99 (95%CrI 0.96-1). PS test sensitivity was 0.03 (95%CrI 0.00-0.0.11) and specificity 0.97 (95%CrI 0.91-1). Combined for use of any of the 3 testing agents, sensitivity was 0.03 (95%CrI 0.00-0.08) and specificity was 0.98 (95%CrI 0.95-1.00). Certainty of evidence was moderate. ST has low sensitivity but high specificity in predicting all-severity repeat immediate allergic reactions to the same agent, among persons with 1st dose immediate allergic reactions to mRNA COVID-19 vaccines. mRNA COVID-19 vaccine or excipient ST has limited risk assessment utility.

Penicillin allergy delabeling: Opportunities for implementation and dissemination.

Although existing as a safety measure to prevent iatrogenic harm, unconfirmed penicillin allergy labels have a negative impact on personal and public health. One downstream effect of unconfirmed penicillin allergy is the continued emergence and transmission of resistant bacteria and their associated health care costs. Recognizing the consequences of inaccurate penicillin allergy labels, professional and public health organizations have started promoting the adoption of proactive penicillin allergy evaluations, with the ultimate goal of removing the penicillin allergy label when the allergy is disproved, also known as penicillin allergy "delabeling." A penicillin allergy evaluation includes a comprehensive allergy history often followed by drug challenge, sometimes with preceding skin testing. Currently, penicillin allergy delabeling is largely carried out by allergy specialists in outpatient settings. Penicillin allergy delabeling is performed on inpatients, albeit rarely, often at the time of need, as a point-of-care procedure. Access to penicillin allergy evaluation services is limited. Recent studies demonstrate the feasibility of expanding penicillin allergy evaluations and delabeling to internists, pediatricians, emergency medicine physicians, infectious diseases specialists, and clinical pharmacists. However, reducing the impact of mislabeled penicillin allergy will require comprehensive efforts and new investments. In this review, we summarize the current practices of penicillin allergy delabeling and discuss expansion opportunities for penicillin allergy delabeling as quality improvement.

Drug allergy in older adults: A study from the United States Drug Allergy Registry.

BACKGROUND: Older adults have an increased risk of adverse drug reactions and negative effects associated with alternative antibiotic use. Although the number of antibiotic allergies reported increases with age, the characteristics and outcomes of older adults receiving drug allergy assessment are unknown. OBJECTIVE: To assess the characteristics and outcomes of drug allergy evaluations in older adults. METHODS: We considered patients aged above or equal to 65 years enrolled in the United States Drug Allergy Registry (USDAR), a US multisite prospective cohort (January 16, 2019 to February 28, 2022). Data were summarized using descriptive statistics. RESULTS: Of 1678 USDAR participants from 5 sites, 406 older adults aged above or equal to 65 years (37% 65-69 years, 37% 70-74 years, 16% 75-79 years, and 10% ≥80 years) received 501 drug allergy assessments. USDAR older adults were primarily of female sex (69%), White (94%), and non-Hispanic (98%). Most USDAR older adults reported less than or equal to 1 infections per year (64%) and rated their general health as good, very good, or excellent (80%). Of 296 (59%) penicillin allergy assessments in USDAR older adults, 286 (97%) were disproved. Other drug allergy assessments included sulfonamide (n = 41, 88% disproved) and cephalosporin (n = 20, 95% disproved) antibiotics. All 41 drug allergy labels in USDAR participants aged above or equal to 80 years and all 80 penicillin allergy labels in USDAR men aged above or equal to 65 years were disproved. CONCLUSION: Older adults represented a quarter of USDAR participants but were neither racially nor ethnically diverse and were generally healthy without considerable antibiotic need. Most older adults presented for antibiotic allergy assessments, the vast majority of which were disproved. Drug allergy assessments may be underutilized in the older adults who are most vulnerable to the harms of unconfirmed antibiotic allergy labels.

Rapid progress in our understanding of COVID-19 vaccine allergy: A cause for optimism, not hesitancy.

Anaphylaxis is a life-threatening condition and when associated with vaccination, leads to vaccine hesitancy. The concerns around vaccine-related anaphylaxis have become even more important during the coronavirus disease 2019 (COVID-19) pandemic where the COVID-19 vaccines remain one of our most important tools. Although rates of anaphylaxis to COVID-19 vaccines are not significantly different from those to other vaccines, Centers for Disease Control and Prevention guidance recommends avoidance of the same COVID-19 vaccine in individuals who had an allergic reaction or are allergic to a COVID-19 vaccine component. Fortunately, our understanding of COVID-19 vaccine allergic reactions has improved dramatically in the past year in large part due to important research efforts from individuals in the allergy community. Initially, researchers published algorithmic approaches using risk stratification and excipient skin testing. However, as our experience and knowledge improved with ongoing research, we have better data showing safety of repeat vaccination despite an initial reaction. We review our progress starting in December 2020 when the Food and Drug Administration approved the first COVID-19 vaccine in the United States through early 2022, highlighting our success in understanding COVID-19 vaccine reactions.

Differential Severe Acute Respiratory Syndrome Coronavirus 2 Antibody Profiles After Allergic Reactions to Messenger RNA Coronavirus Disease 2019 Vaccine.

Allergic symptoms after messenger RNA (mRNA) coronavirus disease 2019 (COVID-19) vaccines occur in up to 2% of recipients. Compared to nonallergic controls (n = 18), individuals with immediate allergic reactions to mRNA COVID-19 vaccines (n = 8) mounted lower immunoglobulin G1 (IgG1) to multiple antigenic targets in severe acute respiratory syndrome coronavirus 2 spike following vaccination, with significantly lower IgG1 to full-length spike (P = .04). Individuals with immediate allergic reactions to mRNA COVID-19 vaccines bound Fcγ receptors similarly to nonallergic controls. Although there was a trend toward an overall reduction in opsonophagocytic function in individuals with immediate allergic reactions compared to nonallergic controls, allergic patients produced functional antibodies exhibiting a high ratio of opsonophagocytic function to IgG1 titer.

COVID-19 severity in asthma patients: a multi-center matched cohort study.

OBJECTIVE: The evidence pertaining to the effects of asthma on Coronavirus disease 2019 outcomes has been unclear. To improve our understanding of the clinically important association of asthma and Coronavirus disease 2019. METHODS: A matched cohort study was performed using data from the Mass General Brigham Health Care System (Boston, MA). Adult (age ≥18 years) patients with confirmed Coronavirus disease 2019 and without chronic obstructive pulmonary disease, cystic fibrosis, or interstitial lung disease between March 4, 2020 and July 2, 2020 were analyzed. Up to five non-asthma comparators were matched to each asthma patient based on age (within 5 years), sex, and date of positive test (within 7 days). The primary outcomes were hospitalization, mechanical ventilation, and death, using multivariable Cox-proportional hazards models accounting for competing risk of death, when appropriate. Patients were followed for these outcomes from diagnosis of Coronavirus disease 2019 until July 2, 2020. RESULTS: Among 562 asthma patients, 199 (21%) were hospitalized, 15 (3%) received mechanical ventilation, and 7 (1%) died. Among the 2686 matched comparators, 487 (18%) were hospitalized, 107 (4%) received mechanical ventilation, and 69 (3%) died. The adjusted Hazard Ratios among asthma patients were 0.99 (95% Confidence Internal 0.80, 1.22) for hospitalization, 0.69 (95% Confidence Internal 0.36, 1.29) for mechanical ventilation, and 0.30 (95% Confidence Internal 0.11, 0.80) for death. CONCLUSIONS: In this matched cohort study from a large Boston-based healthcare system, asthma was associated with comparable risk of hospitalization and mechanical ventilation but a lower risk of mortality.

Accuracy of penicillin allergy diagnostic tests: A systematic review and meta-analysis.

BACKGROUND: Having a penicillin allergy label associates with a higher risk for antibiotic resistance and increased health care use. OBJECTIVE: We sought to assess the accuracy of skin tests and specific IgE quantification in the diagnostic evaluation of patients reporting a penicillin/ß-lactam allergy. METHODS: We performed a systematic review and diagnostic accuracy meta-analysis, searching on MEDLINE, Scopus, and Web of Science. We included studies conducted in patients reporting a penicillin allergy and in whom skin tests and/or specific IgE quantification were performed and compared with drug challenge results. We quantitatively assessed the accuracy of diagnostic tests with bivariate random-effects meta-analyses. Meta-regression and subgroup analyses were performed to explore causes of heterogeneity. Studies' quality was evaluated using QUADAS-2 criteria. RESULTS: We included 105 primary studies, assessing 31,761 participants. Twenty-seven studies were assessed by bivariate meta-analysis. Skin tests had a summary sensitivity of 30.7% (95% CI, 18.9%-45.9%) and a specificity of 96.8% (95% CI, 94.2%-98.3%), with a partial area under the summary receiver-operating characteristic curve of 0.686 (I2 = 38.2%). Similar results were observed for subanalyses restricted to patients reporting nonimmediate maculopapular exanthema or urticaria/angioedema. Specific IgE had a summary sensitivity of 19.3% (95% CI, 12.0%-29.4%) and a specificity of 97.4% (95% CI, 95.2%-98.6%), with a partial area under the summary receiver-operating characteristic curve of 0.420 (I2 = 8.5%). Projected predictive values mainly reflect the low frequency of true penicillin allergy. CONCLUSIONS: Skin tests and specific IgE quantification appear to have low sensitivity and high specificity. Because current evidence is insufficient for assessing the role of these tests in stratifying patients for delabeling, we identified key requirements needed for future studies.

Penicillin Allergy Testing Is Cost-Saving: An Economic Evaluation Study.

BACKGROUND: Having a penicillin allergy label is associated with the use of less appropriate and more expensive antibiotics and increased healthcare utilization. Penicillin allergy testing results in delabeling most allergy claimants and may be cost-saving. This study aimed to project whether penicillin allergy testing in patients reporting a penicillin allergy is cost-saving. METHODS: In this economic evaluation study, we built decision models to project the economic impact of 2 strategies for a patient with a penicillin allergy label: (1) perform diagnostic testing (drug challenges, with or without skin tests); and (2) do not perform diagnostic testing. The health service perspective was adopted, considering costs with penicillin allergy tests, and with hospital bed-days/outpatient visits, antibiotic use, and diagnostic testing. Twenty-four base case decision models were built, accounting for differences in the diagnostic workup, setting (inpatient vs outpatient) and geographic region. Uncertainty was explored via probabilistic sensitivity analyses. RESULTS: Penicillin allergy testing was cost-saving in all decision models built. For models assessing the performance of both skin tests and drug challenges, allergy testing resulted in average savings (in United States [US] dollars) of $657 for inpatients (US: $1444; Europe: $489) and $2746 for outpatients (US: $256; Europe: $6045). 75% of simulations obtained through probabilistic sensitivity analysis identified testing as the less costly option. CONCLUSIONS: Penicillin allergy testing was projected to be cost-saving across different scenarios. These results are devised to inform guidelines, supporting the adoption of policies promoting widespread testing of patients with a penicillin allergy label.

Association of ß-Lactam Allergy Documentation and Prophylactic Antibiotic Use in Surgery: A National Cross-Sectional Study of Hospitalized Patients.

Alternative antibiotics for surgical prophylaxis are associated with increased adverse events and surgical site infection compared to cefazolin. In a sample of perioperative inpatients from 100 hospitals in the United States, cefazolin was 9-fold less likely to be used in patients with a documented ß-lactam allergy whereas clindamycin was 45-fold more likely.

Cutaneous reactions reported after Moderna and Pfizer COVID-19 vaccination: A registry-based study of 414 cases.

BACKGROUND: Cutaneous reactions after messenger RNA (mRNA)-based COVID-19 vaccines have been reported but are not well characterized. OBJECTIVE: To evaluate the morphology and timing of cutaneous reactions after mRNA COVID-19 vaccines. METHODS: A provider-facing registry-based study collected cases of cutaneous manifestations after COVID-19 vaccination. RESULTS: From December 2020 to February 2021, we recorded 414 cutaneous reactions to mRNA COVID-19 vaccines from Moderna (83%) and Pfizer (17%). Delayed large local reactions were most common, followed by local injection site reactions, urticarial eruptions, and morbilliform eruptions. Forty-three percent of patients with first-dose reactions experienced second-dose recurrence. Additional less common reactions included pernio/chilblains, cosmetic filler reactions, zoster, herpes simplex flares, and pityriasis rosea-like reactions. LIMITATIONS: Registry analysis does not measure incidence. Morphologic misclassification is possible. CONCLUSIONS: We report a spectrum of cutaneous reactions after mRNA COVID-19 vaccines. We observed some dermatologic reactions to Moderna and Pfizer vaccines that mimicked SARS-CoV-2 infection itself, such as pernio/chilblains. Most patients with first-dose reactions did not have a second-dose reaction and serious adverse events did not develop in any of the patients in the registry after the first or second dose. Our data support that cutaneous reactions to COVID-19 vaccination are generally minor and self-limited, and should not discourage vaccination.

Penicillin Allergy Evaluation Access: A National Survey.

In a study of 121 hospitals from 38 US states, 44% had access to an allergist for inpatient consultations and 39% had access to inpatient penicillin skin testing, indicating that the majority of US hospitals lack sufficient resources to address inpatient penicillin allergies.

Antibiotic allergy.

Antibiotics are the commonest cause of life-threatening immune-mediated drug reactions that are considered off-target, including anaphylaxis, and organ-specific and severe cutaneous adverse reactions. However, many antibiotic reactions documented as allergies were unknown or not remembered by the patient, cutaneous reactions unrelated to drug hypersensitivity, drug-infection interactions, or drug intolerances. Although such reactions pose negligible risk to patients, they currently represent a global threat to public health. Antibiotic allergy labels result in displacement of first-line therapies for antibiotic prophylaxis and treatment. A penicillin allergy label, in particular, is associated with increased use of broad-spectrum and non-ß-lactam antibiotics, which results in increased adverse events and antibiotic resistance. Most patients labelled as allergic to penicillins are not allergic when appropriately stratified for risk, tested, and re-challenged. Given the public health importance of penicillin allergy, this Review provides a global update on antibiotic allergy epidemiology, classification, mechanisms, and management.

Immunoglobulin G and immunoglobulin G subclass concentrations differ according to sex and race.

BACKGROUND: Serum immunoglobulin G (IgG) concentrations are integral to the workup of immune deficiencies and IgG4-related disease (IgG4-RD). Demographic differences in IgG concentrations are poorly described but can influence test interpretation, contribute to racial disparities in primary immunodeficiency diagnosis, and explain demographic differences in IgG concentrations in IgG4-RD. OBJECTIVE: To assess differences in IgG and IgG subclass concentrations according to sex and race. METHODS: We identified patients with IgG and IgG subclass concentrations measured in a large health care system. Multivariate-adjusted differences in IgG and IgG subclass concentrations and the proportion of subjects with results outside of reference ranges according to sex and race were estimated. RESULTS: Of the 12,851 patients, the mean age was 54.7 years and 7917 (62%) were female. Of these, 11,673 (91%) were white, 611 (5%) were black, and 302 (2%) were Asian. Compared with the mean concentrations of white patients, Asian and black patients had higher mean concentrations of IgG (1340.0 and 1504.4 vs 988.1 mg/dL, P < .001), IgG1 (782.0 and 938.4 vs 592.4 mg/dL, P < .001), IgG2 (493.5 and 384.2 vs 305 mg/dL, P < .001), IgG3 (76.6 and 91.9 vs 55.9 mg/dL, P < .001), and IgG4 (140.4 and 53.6 vs 41.6 mg/dL, P < .001). Immunoglobin G subclass 4 concentrations were higher in males than those in females (56.3 vs 37.4 mg/dL, P < .001). Similar observations were made when comparing the proportions of patients with results outside of reference ranges and after stratifying by diagnosis. CONCLUSION: Immunoglobin G and IgG subclass concentrations differ according to sex and race. These findings may have implications for the interpretation of these test results but require confirmation in diverse, healthy populations.

Preoperative penicillin allergy testing in patients undergoing cardiac surgery.

BACKGROUND: Cefazolin is a first-line prophylactic antibiotic used to prevent surgical site infections (SSIs) in cardiac surgery. Patients with a history of penicillin allergy often receive less effective second-line antibiotics, which is associated with an increased SSI risk. OBJECTIVE: To describe the impact of preoperative penicillin allergy evaluation on perioperative cefazolin use in patients undergoing cardiac surgery. METHODS: We performed a retrospective cohort study of patients with a documented penicillin allergy who underwent cardiac surgery at the Massachusetts General Hospital from September 2015 to December 2018. We describe penicillin allergy evaluation assessment and outcomes. We evaluated the association between preoperative penicillin allergy evaluation and first-line perioperative antibiotic use using a multivariable logistic regression model. RESULTS: Of 3802 cardiac surgical patients, 510 (13%) had a documented penicillin allergy; 165 (33%) were referred to allergy and immunology practitioners. Of 160 patients (31%) who underwent penicillin allergy evaluation (ie, penicillin skin testing and, if results were negative, an amoxicillin challenge), 154 (97%) were found not to have a penicillin allergy. Patients who underwent preoperative penicillin allergy evaluation were more likely to receive the first-line perioperative antibiotic (92% vs 38%, P < .001). After adjusting for potential confounders, patients who underwent preoperative penicillin allergy evaluation had higher odds of first-line perioperative antibiotic use (adjusted odds ratio, 26.6; 95% CI, 12.8-55.2). CONCLUSION: Integrating penicillin allergy evaluation into routine preoperative care ensured that almost all evaluated patients undergoing cardiac surgery received first-line antibiotic prophylaxis, a critical component of SSI risk reduction. Further efforts are needed to increase access to preoperative allergy evaluation.

Sex differences in academic rank in allergy/immunology.

BACKGROUND: Female physicians are significantly less likely than male physicians to be full professors, even after accounting for age, experience, specialty, and measures of research and clinical productivity. OBJECTIVE: We sought to evaluate sex differences in academic rank in the allergy and immunology workforce. METHODS: We used a cross-sectional physician data set containing the allergist's sex, age, years since residency, faculty appointment, authored publications, National Institutes of Health (NIH) funding, clinical trial investigation, and Medicare reimbursement to investigate sex differences in the academic allergy and immunology workforce using multilevel logistic regression models. RESULTS: Among 507 academic allergists (9.3% of practicing US allergists in 2014), 323 (63.7%) were men, and 184 (36.3%) were women. Female allergists were younger (47.9 vs 56.9 years, P < .001), had fewer total (12.5 vs 28.7, P < .001) and first/last author (8.0 vs 21.5, P < .001) average publications, were less likely to have NIH funding (13.0% vs 23.5%, P = .004), were less frequently a clinical trial investigator (10.3% vs 16.1%, P = .07), and generated less average annual Medicare revenue ($44,000 vs $23,000, P = .10). Of 152 (30.0%) full professors, 126 (82.9%) were male, and 26 (17.0%) were female. After multivariable adjustment, rates of full professorship among female and male allergists were not significantly different (absolute adjusted difference for female vs male allergists, 6.0%; 95% CI, -8.3% to 20.2%). CONCLUSIONS: Among allergists with US medical school faculty appointments, men and women were similarly likely to be full professors after accounting for factors influencing promotion. Underlying differences in research productivity and NIH funding not explained by age differences alone warrant additional investigation.