P351 SARS-CoV-2 infection and seroconversion in pediatric patients on biological therapy for Crohn’s disease: single tertiary center experience

SÅ‚adek, M; Krucka-Kawalec, M; Wojtas, E; Jagielski, P; Stochel-Gaudyn, A

BACKGROUND: It is still unclear how SARS-CoV-2 infection affect Crohn’s disease (CD) patients and how seroconversion against the virus might take place depending upon disease states and treatments. While the clinical guidance recommended to continue the biological maintenance therapy, some suggestions advice postponing the start of biologic agents. MATERIALS AND METHODS: Medical records of all patients undergoing biologic therapy with infliximab, adalimumab, or vedolizumab for mild-to moderate CD followed in our institution were enrolled in the analysis. Demographic parameters, disease characteristics, clinical course, concomitant medications, COVID-19 related symptoms were examined. A naso-pharyngeal swab based RT-PCR testing for SARS-CoV-2 was taken and SARS-CoV-2 serology test was performed using SARS-CoV-2 Immunoassay (Abbott Core Laboratory) in children treated between March 4th 2020 and March 3rd 2021. Every time before hospital admission parents or patients completed a questionnaire exploring the presence of symptoms suggestive of SARS-CoV-2 infection. RESULTS: Of the 62 children (35 boys, 56%) aged 2-19 years, median 15 ±3,51 years, 47 (76%) were treated with infliximab, 12 (19%) with adalimumab, and 3 (5%) with vedolizumab including 23 (37%) patients on the induction regiment. Of the entire cohort 11 (18%) patients were on a concomitant immunemodulator, including 6 (55%) on thiopurines, and 5 (45%) on methotrexate. A total of 19 (30%) CD patients tested positively for SARS-CoV-2. Only 5 (26%) patients reported symptoms including fever (n=3, 16%), sore throat (n=1, 5%), cough (n=2, 11%), loss of smell (n=2, 11%), loss of taste (n=1, 5%), and 14 (74%) were asymptomatic. All symptomatic patients had mild clinical presentation, and no patients required hospitalization. Swab test was positive in 8 (13%) patients, including 3 (5%) patients with nonreactive antibody titers. Of the 19 patients, 5 (23%) had elevated SARS-CoV-2 IgG titers, while 14 (74%) had elevated SARS-CoV-2 IgM. Four had elevated both IgG and IgM titers, and 2 of them had acute, mild and resolved symptoms. Biologic agent administration was postponed for 6±5,4 days in 6 patients due to positive swab test, but no other management alteration was needed. No exacerbation of CD was observed attributed to SARS-CoV-2 infection during either induction or maintenance therapy in the studied cohort CONCLUSION: Many patients with SARS-CoV-2 infection remained asymptomatic or presented mild symptoms, and did not develop COVID-19. Biologic therapy did not worsen CD course. Serological testing might provide an accurate estimate of the cumulative prevalence of SARS-CoV-2 infection by detecting subclinical and asymptomatic infected individuals.