Immunogenicity and reactogenicity in UK infants of a novel meningococcal vesicle vaccine containing multiple class 1 (PorA) outer membrane proteins

The development of effective vaccines against serogroup B meningococci is o f great public health importance. We assessed a novel genetically engineere d vaccine containing six meningococcal class 1 (PorA) outer membrane protei ns representing 80% of prevalent strains in the UK. 103 infants were given the meningococcal vaccine at ages 2, 3 and 4 months with routine infant imm unisations. with a fourth dose at 12-18 months. The vaccine was well tolera ted. Three doses evoked good immune responses to two of six meningococcal s trains expressing PorA proteins contained in the vaccine. Following a fourt h dose, larger bactericidal responses to all six strains were observed, sug gesting that the initial course had primed memory lymphocytes and revaccina tion stimulated a booster response. This hexavalent PorA meningococcal vacc ine was safe and evoked encouraging immune responses in infants. Vaccines o f this type warrant further development and evaluation. (C) 1999 Elsevier S cience Ltd. All rights reserved.