105 - SAFETY AND TOLERABILITY OF COVID-19 VACCINATION IN INFANTS WITH A HISTORY OF KAWASAKI DISEASE

Background: There is a high likelihood that patients diagnosed with Kawasaki Disease (KD), a common childhood vasculitis, will be exposed to SARS-CoV-2. COVID-19 vaccine uptake in children < 5 years is generally low, and parents of children with KD and providers may have additional concerns about COVID-19 vaccine safety. Therefore, vaccine safety and tolerability in these patients must be defined to reassure providers and families. We evaluated the safety and tolerability of COVID-19 vaccination in infants with a history of KD.   

Methods: Five children < 5 years of age with a history of KD were primarily vaccinated with BNT162b2 mRNA vaccine (3-dose series) and followed for at least 6 months. Prospective reactogenicity data with accompanying impact on daily life were collected by daily survey for 7 days following each vaccine dose. Immunologic response, including quantitative SARS-CoV-2 anti-spike IgG titers, were determined at baseline and serial timepoints after vaccinations.   

Results: All patients met the American Heart Association diagnostic criteria for complete or incomplete KD and were diagnosed with KD at a median age of 6.5 months (range 3.8-27 months). Coronary abnormalities were present in all 5 patients. All patients were treated with IVIG; 3 of 5 also received corticosteroids and/or biologic therapy.  

Patients received their first COVID-19 vaccine 3-35 months after diagnosis (age range 9-53 months at first vaccination) and completed 3 doses by 15-56 months of age. All 5 patients had minimal reactogenicity to the vaccinations. The most frequently reported symptom after vaccination was subjective fever in 2 patients described as no real burden. No serious adverse event was reported. There have been no inflammatory flares during follow-up to date, including no flare in one patient who developed acute COVID-19 with consistent clinical symptoms and a known sick contact, during the study period. Four of 5 patients had a 4-fold or greater increase in anti-spike IgG titers after their first vaccine (the fifth had no initial response), but maintenance of vaccine titers over time was highly variable. 

Conclusions: This prospectively followed cohort of infants with a history of KD tolerated COVID-19 mRNA vaccination with minimal reactogenicity as soon as 3 months after their KD diagnosis and had no inflammatory flares during follow-up. This evaluation, although limited by small sample size, suggests that patients with a history of KD can be safely offered COVID-19 vaccination.