Ab0420 maternal and neonatal antibody levels upon pertussis vaccination in pregnant women on immune-modulating therapy for rheumatic disease

Background While protection against pertussis following maternal tetanus-diphtheria-and-acellular-pertussis (Tdap) vaccination has been demonstrated in term-born infants from healthy mothers[1], no evidence is available on Tdap vaccination in combination with immune-modulating therapy during pregnancy. Objectives In this pilot-study, we explored whether treatment with Tumor Necrosis Factor alpha inhibitors (TNFis) in pregnant patients with rheumatic disease interferes with Tdap vaccine responses and/or affects maternal IgG antibody concentrations against the relevant antigens in the newborns. Methods Patients included by a rheumatologist during pregnancy received a Tdap vaccination in their late-second or early-third trimester. Blood samples were drawn during the first trimester, three months after delivery and from the umbilical cord. IgG antibody levels against Tdap-included antigens were measured using a bead-based multiplex immunoassay. Findings on patients exposed to TNFis were compared with those from TNFi-unexposed patients and with data from a historical comparator study among healthy Tdap vaccinated mother-infant-pairs (n=53). [2] Results 66 patients (46 exposed and 20 unexposed to TNFIs) were enrolled. No differences in IgG antibody levels against Tdap-included antigens were observed between TNFi-exposed and unexposed patients before and after Tdap vaccination (Figure 1). In cord sera however, antibody levels against pertussis toxin were significantly lower after TNFi-treatment (35.94IU/mL, 95%CI 20.68-62.45) compared with no TNFis (94.61IU/mL, 95%CI 48.89-183.07) and with cord blood from the comparison cohort of healthy women-infant-pairs (125.12IU/mL, 95%CI 90.75-172.50). We observed similar differences for filamentous hemagglutinin, pertactin, tetanus toxoid, and diphtheria toxoid. Conclusion These preliminary data indicate no reduced IgG antibody response upon maternal Tdap vaccination in pregnant women following immune-modulating treatment, although our findings suggest that TNFis during pregnancy induce lower maternal antibody levels against Tdap-included antigens in newborns. References [1] Byrne L, Campbell H, Andrews N, Ribeiro S, Amirthalingam G. Hospitalisation of preterm infants with pertussis in the context of a maternal vaccination programme in England. Arch Dis Child. 2018;103(3):224-9. [2] Barug D, Pronk I, van Houten MA, Versteegh FGA, Knol MJ, van de Kassteele J, et al. Maternal pertussis vaccination and its effects on the immune response of infants aged up to 12 months in the Netherlands: an open-label, parallel, randomised controlled trial. Lancet Infect Dis. 2019;19(4):392-401. Figure 1. Anti-Pertussis toxin (anti-PT IgG) concentrations (IU/mL) before and after vaccination and in cord sera, represented for women exposed or unexposed to TNFis, or healthy pregnant women, including their offspring. X-axis: type and time-point of blood sample draw. Y-axis: IgG antibody concentration against pertussis toxin (IU/mL). Significance *p<0.05, **p<0.01, ***p<0.001. Acknowledgements: NIL. Disclosure of Interests Nafise Ghalandari Grant/research support from: Financial support for printing PhD book from UCB Pharma., Employee of: From June 2022 till February 2023 worked as a medical science liaison (MSL) at UCB Pharma., Maarten Immink: None declared, Esther Röder: None declared, Patricia Bruijning-Verhagen: None declared, Hieronymus TW Smeele: None declared, Hubertina Johanna Maria Josephina Crijns: None declared, Nicoline van der Maas: None declared, Mireille Bekker: None declared, Lieke Sanders: None declared, Radboud Dolhain Speakers bureau: from AbbVie, AstraZeneca, Eli Lily, Galapagos, Novartis, Roche, UCB., Grant/research support from: an unrestricted grant from Galapagos, UCB Pharma B.V.