Covid-19 Vaccination and Chronic Urticaria: A Paradigm Study

Background

Multiple vaccines were introduced during 2020-2021 to combat Covid-19 pandemic, being one of the successful vaccine programmes in the present era. Very few studies are available on status of chronic urticaria (CU) post Covid-19 vaccination.

Aim

The aim of this study was to study effect of Covid-19 vaccination on our urticaria cohort.

Materials and Methods

In this retrospective study, case records of CU patients registered in urticaria clinic, who had received any type of Covid-19 vaccine during the interval of March 2021-2022 were retrieved. Patients were classified as 'vaccine induced urticaria' (VIU) when CU developed for first time post-vaccination and 'vaccine exacerbated urticaria' (VEU) when administration of vaccine exacerbated disease activity in previously diagnosed CU.

Results

Overall, 353 CU patients registered with us during this period, 265 had received atleast one dose of a Covid-19 vaccine, of which 12 reported VEU (ten of whom had received adenovirus vector vaccine), and three patients were diagnosed with VIU (all had received inactivated virus vaccine). Mean vitamin D3 levels were significantly higher in patients who had VEU as compared to those CU patients without exacerbation (p = 0.003). Significant correlation was observed between level of concern regarding adverse effects of vaccination, pre-vaccination, and post-vaccination urticaria activity score (UAS-7), (Pearson correlation coefficient = 0.66, P = 0.007) in both VEU and VIU. Urticaria symptoms were controlled in 75% and 66.6% patients, respectively, of VEU and VIU, after one month of initiating standard antihistamine treatment.

Conclusion

Hence, we conclude that though Covid-19 vaccines can trigger CU, standard treatment protocols control disease activity in most patients.

Anti-PF4 testing for vaccine-induced immune thrombocytopenia and thrombosis and heparin induced thrombocytopenia: Results from a UK National External Quality Assessment Scheme exercise April 2021

BACKGROUND

Vaccine-induced immune thrombocytopenia and thrombosis (VITT) following the administration of the AstraZeneca (AZ) ChAdOx1 nCOV-19 vaccine has recently been reported. The associated clinical and laboratory features have included thrombosis at unusual sites, thrombocytopenia, and raised D-dimers with positivity for IgG anti-platelet factor 4 (PF4) antibodies.

OBJECTIVES

A UK National External Quality Control Assessment Scheme external quality control exercise was carried out by distributing liquid and lyophilized samples from a subject with VITT, a pool of samples from subjects with classical heparin-induced thrombocytopenia (HIT), and a non-VITT/non-HIT case to 85 centers performing HIT testing.

METHODS

Participating centers employed their locally validated testing methods for HIT assays.

RESULTS

The lyophilized and liquid samples were found to be commutable for the ELISA assays used in the detection of anti-PF4 antibodies. The Aeskulisa, Stago, Hyphen, and LIFECODES anti-PF4 ELISA assays successfully detected the VITT antibody, whereas the Acustar HIT, Werfen LIA, and the Stago STIC assays did not.

CONCLUSION

It is important that clinical and laboratory teams are aware of the limitations of some anti-PF4 assays when using them to aid diagnosis of VITT syndrome.