Table 1.

Effect of previous clinical malaria episodes and present infections on antibody levels to whole parasite (IFAT), MSP-1₁₉, AMA-1, and EBA-175^a

Antigen	Antibody	Result by exposure to malaria
		Previous malaria episodeb			Present infectionc
		Proportional difference	95% CI	P value	Proportional difference	95% CI	P value
Whole P	IgG	2.85	2.10–3.86	<0.0001	1.84	1.37–2.47	<0.0001
MSP-119	IgG	2.05	1.76–2.39	<0.0001	1.31	1.14–1.51	0.0001
	IgG1	2.56	2.05–3.19	<0.0001	1.94	1.59–2.37	<0.0001
	IgG2	1.14	1.06–1.23	0.0003	1.13	1.06–1.21	0.0003
	IgG3	2.31	1.89–2.83	<0.0001	1.74	1.42–2.14	<0.0001
	IgG4	1.16	1.10–1.23	<0.0001	1.09	1.03–1.16	<0.004
	IgM	NS	NS	NS	1.28	1.11–1.48	0.0005
AMA-1	IgG	1.78	1.54–2.05	<0.0001	1.26	1.10–1.43	0.0007
	IgG1	1.49	1.24–1.81	<0.0001	1.44	1.22–1.71	<0.0001
	IgG2	1.06	1.00–1.12	0.0444	1.10	1.04–1.15	0.0006
	IgG3	1.86	1.57–2.20	<0.0001	1.52	1.28–1.82	<0.0001
	IgG4	1.06	1.01–1.12	<0.0111	1.09	1.04–1.15	0.0004
	IgM	NS	NS	NS	1.25	1.12–1.39	0.0001
EBA-175	IgG	1.18	1.06–1.31	0.0025	1.12	1.01–1.24	0.026
	IgG1	1.22	1.00–1.49	0.0448	NS	NS	NS
	IgG2	NS	NS	NS	NS	NS	NS
	IgG3	NS	NS	NS	1.32	1.08–1.62	0.007
	IgG4	NS	NS	NS	NS	NS	NS
	IgM	NS	NS	NS	1.15	1.02–1.29	0.023

^aMultivariate random-effect models estimated by stepwise procedure and adjusted by age and neighborhood of residence. NS, not significant in the forward stepwise procedure (P-enter = 0.05, from likelihood ratio test).

^bNumber of children who had previous clinical episodes: 18 at 5 months, 54 at 9 months, 60 at 12 months, and 82 at 24 months.

^cNumber of children with current parasitemia (detected by microscopy or PCR): 36 children at 5 months, 62 at 9 months, 37 at 12 months, and 78 at 24 months.