Table 1.

Bactericidal titers by vaccination status.

MenW isolate	MenACWY vaccine		4CMenB vaccine
	Adolescents		Adolescents		Infants
	Pre-immune	Post-immune	Pre-immune	Post-2nd dose	Control sera	Post-4th dose
ARG-2991	<16	256	<4	<4	<2	<2
ARG-3006	<16	>512	<4	>128*	<2	>64
ARG-3052	<16	256	<4	>128	2	>64†
ARG-3064	<16	256	<4	>128	<2	>64
ARG-3158	<16	>512	<4	64*	<2	>64
ARG-3200	<16	256	<4	>128	<2	>64
ARG-3216	<16	256	<4	>128	<2	>64*
ARG-3223	<16	256	4	>128	2	>64
ARG-3273	<16	>512	<4	>128*	<2	>64*
ARG-3279	<16	≥512	<4	64	<2	>64
ARG-3320	<16	≥512	<4	>128*	<2	>64

*Prozone effect: bacterial survival was observed at high antibody concentrations due to the prozone effect, which is often detected when there is an excess of antibodies.

^†Bacteriostatic.

4CMenB, 4-component meningococcal serogroup B vaccine; ARG, Argentina; MenACWY, meningococcal serogroups A, C, W, and Y; MenW, meningococcal serogroup W.