In patients with hereditary angioedema (HAE), the administration of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) messenger RNA (mRNA) vaccines is safe and effective, according to the results of a prospective, observational study conducted at the Campania Referral Center for Recurrent Angioedema, University of Naples Federico II in Italy and published in Vaccines.

The researchers sought to gain insight into the benefits and potential risks associated with coronavirus disease 2019 (COVID-19) mRNA vaccination in patients with HAE, with a particular focus on the possibility of triggering attacks.

To assess the possible impact of the vaccine on disease control and attack frequency, they administered the angioedema control test (AECT) 4-week version prior to vaccine administration (T0), 21 days after the first dose was administered (T1), and 21 to 28 days after the second dose was administered (T2).

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The AECT is a self-administered 4-item patient-reported outcome measure for individuals with current angioedema. A score between 0 and 4 is assigned to each AECT response. The AECT total score can range from 0 to 16, with a higher score indicative of a higher level of disease control.

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Thirty-one patients with HAE from the center in Naples, Italy, were enrolled in the study, 22 of whom were female and 9 who were male. All of the participants received 2 doses of the SARS-CoV-2 mRNA Comirnaty-BioNTech/Pfizer vaccine.

Study inclusion criteria were (1) a physician diagnosis of HAE, (2) written informed consent, and (3) available information on sex, patient demographics, age at onset of HAE, and diagnosis. Patients who reported a positive history of COVID-19 infection were excluded from the study. Eighteen healthy age- and sex-matched individuals without a prior COVID-19 infection served as the controls.

During each follow-up visit, the participants were asked about any vaccine-related adverse events they had experienced, using a standardized questionnaire to learn more about the safety and tolerability of vaccination in individuals with HAE.

Results showed that despite 5 of the patients experiencing an attack within 72 hours of the first dose, no statistically significant variation in frequency of attacks was observed prior to or following vaccination (P =.799).

Furthermore, patients reported significantly higher AECT scores at T1 and T2 than at T0 (P <.05; post hoc P <.05), which demonstrated that the disease was more controlled following vaccination. Additionally, all patients showed a positive serologic response to the vaccine without any significant differences from the healthy controls (P =.062). 

“In conclusion, our findings suggest HAE patients can be safely vaccinated against COVID-19 . . . providing the availability of an effective on-demand attack treatment,” the authors wrote.


Mormile I, Gigliotti MC, Petraroli A, et al. Immunogenicity and safety of anti-SARS-CoV-2 mRNA vaccines in a cohort of patients with hereditary angioedema. Vaccines (Basel). Published online January 18, 2023. doi:10.3390/vaccines11020215