Poster Presentations

Session Title: VACCINE AND PREVENTION

BACTERICIDAL ACTIVITY AGAINST AN EXTENDED PANEL OF MENINGOCOCCAL STRAINS FOLLOWING IMMUNISATION WITH NOVEL SEROGROUP B MENINGOCOCAL VACCINES IN INFANCY

E.L. Su¹, M.D. Snape¹, T. Dawson¹, A. Morant¹, T. John¹, B. Ohene-Kena¹, R. Borrow², J. Findlow², P. Oster³, E. Miller⁴, A.J. Pollard^1
1Oxford Vaccine Group, University of Oxford, Oxford, ²Vaccine Evaluation Unit, Health Protection Agency, Manchester, UK, ³Global Medical Affairs, Novartis Vaccines, Siena, Italy, ⁴Centre for Infections, Health Protection Agency, London, UK

Background: We previously reported that ≥93% of infants completing an early infant (2, 4, 6 and 12 month) or a late infant (6, 8 and 12 month) course of a serogroup B meningococcal (MenB) vaccine (rMenB+OMV) had human complement serum bactericidal antibody (hSBA) titres ≥1:4 against 3 meningococcal strains (44/76-SL, NZ98/254 and 5/99) expressing the vaccine antigens.
Methods: Sera obtained after completion of early or late infant courses of rMenB (containing factor H binding protein (fHBP) sub-variant 1.1, NadA and GNA2132) or rMenB+OMV (rMenB plus outer membrane vesicles from strain NZ98/254, expressing PorA P1.7-2,4) were tested for hSBA using 4 additional MenB strains: M00-242922 (ST:41, fHBP1.4, NadA-ve, PorA:P1.7-2,4); M01-240101 (ST:1049, fHBP1.11, NadA-ve, PorA:1.19-1,15-11); M01-240355 (ST:213, fHBP3.4, NadA low expression, PorA:P1.22,14) and M01-240364 (ST:11, fHBP 3.4, NadA+ve, PorA:P1.5,2).
Results: After an early infant course of rMenB+OMV, 80% of participants had hSBA titres ≥1:4 against M00-242922 (PorA homologous), 57% against M01-240101 (contains related fHBP), 11% against M01-240355 (fHBP, PorA and NadA heterologous) and 78% against M01-240364 (NadA homologous). After a late infant rMenB+OMV course, 100% of participants had hSBA titres ≥1:4 against M00-242922, 70% against M01-240101, 17% against M01-240355 and 90% against M01-240364.
For these four strains, rMenB alone was only immunogenic for M01-240364 (hSBA ≥1:4 in 70% (early infant) and 88 % (late infant) participants).
Conclusion: These data confirm that a course of rMenB+OMV in early or late infancy induces bactericidal antibody against strains expressing the vaccine antigens, further demonstrating the potential for improved vaccine prevention of MenB disease.