POS0258 SAFETY AND IMMUNOGENICITY OF BNT162b2 Mrna COVID-19 VACCINE AMONG ADOLESCENTS WITH RHEUMATIC DISEASES TREATED WITH IMMUNOMODULATORY MEDICATIONS

Background Adolescents with juvenile-onset autoimmune inflammatory rheumatic diseases (AIIRD) could be at risk for disease flare secondary to SARS-CoV-2 infection or to withholding anti-inflammatory therapy. While vaccination can protect against COVID-19, safety and immunogenicity data regarding anti-SARS-CoV-2 vaccines among adolescents with AIIRD are limited. Objectives This international, prospective, multicentre study evaluated the safety and immunogenicity of the BNT162b2 anti-SARS-CoV-2 vaccine among adolescents and young adults with juvenile-onset AIIRD, 80% of whom are on chronic immunomodulatory therapy. Methods Vaccine side effects, disease activity, and short-term efficacy were evaluated after 3 months in 91 patients. Anti-spike S1/S2 IgG antibody levels were evaluated in 37 patients and 22 controls, 2–9 weeks after the second dose. Results Ninety-one patients and 40 healthy controls were included. Safety profile was good, with 96.7% (n=88) of patients reporting mild or no side-effects, and no change in disease activity. However, 3 patients had transient acute symptoms: 2 following the first vaccination (renal failure and pulmonary haemorrhage) and 1 following the second dose (mild lupus flare vs. viral infection). Seropositivity rate was 97.3% in the AIIRD group compared with 100% among controls. However, anti-S1/S2 antibody titres were significantly lower in the AIIRD group compared with controls (242±136.4 vs. 387.8±57.3 BAU/ml, respectively; p<0.0001). No cases of COVID-19 were documented during the 3-month follow-up. Conclusion Vaccination of juvenile-onset AIIRD patients demonstrated good short-term safety and efficacy, high seropositivity rate, but lower anti-S1/S2 antibody titres compared to healthy controls. These results should encourage vaccination of adolescents with juvenile-onset AIIRD, even while on immunomodulation. References [1]Fact sheet for healthcare providers administrating vaccine emergency use authorization (EUA) of the Pfizer-BioNTech COVID-19 vaccine to prevent coronavirus disease 2019 (COVID-19) for 12 years of age and older dilute before use for 12 years of age and old; Available from: www.cvdvaccine.com . [2]Polack FP, Thomas SJ, Kitchin N, Absalon J, Gurtman A, Lockhart S, et al. Safety and efficacy of the BNT162b2 mRNA Covid-19 vaccine. N Eng J Med 2020;383:2603–15. DOI: 10.1056/NEJMoa2034577 [3]Frenck RW, Klein NP, Kitchin N, Gurtman A, Absalon J, Lockhart S, et al. Safety, immunogenicity, and efficacy of the BNT162b2 Covid-19 vaccine in adolescents. N Eng J Med 2021;385:239–50. [4]First COVID-19 vaccine approved for children aged 12 to 15 in EU | European Medicines Agency [Internet]. [cited 2022 Jan 3]. Available from: https://www.ema.europa.eu/en/news/first-covid-19-vaccine-approved-children-aged-12-15-eu [5]FDA authorizes Pfizer-BioNTech COVID-19 vaccine for emergency use in children 5 through 11 Years of Age | FDA [Internet]. [cited 2022 Jan 1]. Available from: https://www.fda.gov/news-events/press-announcements/fda-authorizes-pfizer-biontech-covid-19-vaccine-emergency-use-children-5-through-11-years-age [6]Woodworth KR, Moulia D, Collins JP, Hadler SC, Jones JM, Reddy SC, et al. The Advisory Committee on Immunization Practices’ Interim Recommendation for Use of Pfizer-BioNTech COVID-19 Vaccine in Children Aged 5–11 Years — United States, November 2021. MMWR Morbidity and Mortality Weekly Report [Internet]. 2021 Nov 12 [cited 2021 Dec 1];70(45):1579–83. Available from: https://www.cdc.gov/mmwr/volumes/70/wr/mm7045e1.htm [7]Liguoro I, Pilotto C, Bonanni M, Ferrari ME, Pusiol A, Nocerino A, et al. SARS-COV-2 infection in children and newborns: a systematic review. Eur J Pediatr 2020;179:1029–46. Acknowledgements We thank the families and adolescents who participated in the study. We thank Mr. Yishai Friedlander, MPH, for performing the statistical analysis. We thank Faye Schreiber, MS, for editing the manuscript. Disclosure of Interests None declared