P460 Impact of anti-TNFα exposure during pregnancy for maternal inflammatory bowel disease on serologic response to vaccination of exposed children

Abstract

Anti-TNFα therapy is increasingly used during pregnancy for women with inflammatory bowel disease (IBD). Thus, the knowledge on long-term evolution of exposed children, including response to vaccinations is crucial. A recent study demonstrated an adequate response to two non-live vaccines in 71% and 80% of exposed infants.1 Our aim was to assess the impact of anti-TNFa exposure in utero for maternal IBD on serologic response to vaccinations in exposed children. We prospectively included consecutive children (≥12 months of age) born to mothers with IBD (2007–2016) treated with anti-TNFa during pregnancy in three medical centres in Czech Republic. Data on birth, perinatal period, psychomotor development, vaccination, infections, antibiotic use and atopy were collected by treating paediatricians from children’s medical files using a predefined questionnaire. Furthermore, a subset of children had a blood sample taken for assessment of immunologic parameters including serologic response to vaccination: (A) non-live vaccines (given within the first year of live): Haemophilus influenza B-HiB, tetanus-TET, diphtheria-DIF, Streptococcus pneumoniae-PNE; (B) live vaccines (given since 15th month of life): parotitis-PAR, rubeola-RUB, morbilli-MOR. Sixty-nine exposed children were included (47.8% girls, median age 35.4 months at last follow-up). Of them, 45 (65.2%) children had a blood sample taken at a median age of 34.8 months. After completion of vaccination protocol, protective antibodies to all non-live vaccines were detected in 63.6% of children while 36.4% of them had inadequate response to at least one non-live vaccine: 23.2% to HiB, 4.5% to TET and 2.4% to PNE. Regarding live-vaccines, protective titres of antibodies were found in 71.4% of vaccinated children and 28.6% had insufficient titres: 25.7% to PAR and 2.9% to each of MOR and RUB. Anti-TNFα levels in cord blood were available for 25 children with blood samples. No significant difference in proportion of protective antibodies to non-live or live vaccines was observed comparing children with a therapeutic (≥3 μg/ml) vs. non-therapeutic cord levels of anti-TNFα (p > 0.05). Two-thirds of children exposed to anti-TNFα in utero had adequate serologic response to non-live and/or live vaccines which is in agreement with findings of a previous study.1 The highest rate of inadequate response to vaccination was observed in case of haemophilus and parotitis vaccines. A control group of unexposed children is needed to assess the vaccination response in general paediatric population. 1. Beaulieu et al. Use of biologic therapy by pregnant women with inflammatory bowel disease does not affect infant response to vaccines. CGH 2017.