Analysis of the Serologic Response to Covid-19 Vaccination in Paediatric Inflammatory Bowel Disease

ABSTRACT

Introduction: Paediatric Inflammatory Bowel Disease (pIBD) is a chronic disease that often requires immunosuppressive drugs such as glucocorticoids, thiopurines or biologic therapy, which may attenuate the response to certain vaccines. The SARS-CoV2 pandemic in 2020 prompted the rapid development of multiple vaccines and, although there are not many studies regarding their response in patients with IBD, it seems that there are differences in adults patients in relation to the treatment they receive. To the best of our knowledge, there is no literature on paediatric patients with IBD. In July 2021, vaccination against COVID 19 was authorised for adolescent patients from 12 years old. Aims & Methods: The aim of the present study is to assess the response to COVID-19 vaccination in pIBD patients. A prospective study was conducted in a tertiary hospital from July to December 2021 including pIBD patients from 12 to 18 years of age who agreed to be vaccinated. We determined baseline COVID-19 serostatus and analysed the serologic response after the complete vaccination regimen 1 dose (patients with previous COVID- 19 infection) or 2 doses (those with no previous infection) of mRNA vaccine. During this period, three different immunoassay tests have been used for the semi-quantitative and qualitative determination of IgG antibodies against SARS-CoV2, which use different units of measurement and are not comparable with each other. We recorded clinical and epidemiological data. Statistical analysis was performed using SPSS software. Result(s) We included a total of 33 patients, 19 (56%) were male. The median age was 14.85 years (age range from 12 to 17.7). A total of 26 (79%) were diagnosed with Crohn's Disease, five (15%) with Ulcerative Colitis and two (6%) with unclassified IBD. Up to 23 patients (70%) were receiving biologic treatment and 20 (61%) had immunosuppressive treatment. Eight participants (24%) have undergone a COVID-19 infection, and in all cases reported mild or non-existent symptoms seven of them (88%) were infected before the vaccination and only one (12%) after it. A total of 32 patients (97%) received the BioNTech/Pfizer vaccine (COMIRNATY) and one received MODERNA. Only five participants (15%) reported side effects after the vaccination, and these were in all cases mild (myalgia, headache, and low-grade fever, lasting less than 24 hours). Both the baseline and the post-vaccination serologic status were determined in 22 patients, and in seven patients only the post-vaccination status was carried out. All of them showed an adequate serologic response after the complete vaccination regimen. The development of adverse effects was independent of having suffered COVID-19 (p=0.17) and independent of treatment (p= 0.12). We found no statistical differences between patients receiving thiopurines or biologic treatment versus those without this kind of treatment (p=0.253 and p=0.521 respectively). Conclusion(s) The present preliminary study suggests that the pIBD population show an adequate response to the recommended vaccination regimen and the approved vaccines seem to be safe in this group of patients. Receiving thiopurines or biologictreatment did not seem to influence the serologic response. However, the small number of patients and the impossibility to compare antibody levels with different tests, limits the drawing of conclusions. Further studies are needed to stablish the duration and efficacy of the protective effect against COVID-19, and the potential need of a booster dose of the vaccine for pIBD patients.