Table 5.

Association between age at the time of malaria episode and antibody levels and seroprevalence in 18 months old children

Antigen tested/parasite isolate	No episodea (n = 457)	≥ 1 episode before 6 months of agea (n = 31)	p valueb	≥ 1 episode between 6 and 18 months of agea (n = 113)	p valueb
MSP1 19 kDc	2.36 (0.51, 5.73)	6.16 (1.92, 11.16)	0.0071	4.71 (1.43, 21.25)	< 0.0001
	224 (49.0)	24 (77.5)	0.002	79 (69.9)	< 0.0001
MSP2d	2.76 (0.79, 8.23)	5.76 (1.01, 10.55)	0.1043	3.06 (1.06, 13.97)	0.3165
	113 (24.7)	12 (38.8)	0.084	37 (32.7)	0.083
EBA175e	3.49 (1.96, 17.05)	3.25 (1.89, 8.79)	0.5785	3.19 (1.93, 9.91)	0.3753
	50 (10.9)	3 (9.7)	0.827	16 (14.2)	0.338
Rh2A9f	7.03 (3.97, 13.13)	8.24 (4.41, 17.32)	0.3790	7.92 (4.12, 15.87)	0.2223
	108 (23.6)	10 (32.3)	0.278	33 (29.2)	0.219
Schizont	2.95 (1.02, 7.24)	7.40 (2.24, 13.97)	0.0211	4.70 (1.77, 14.87)	0.0018
	222 (48.6)	23 (74.2)	0.006	80 (70.8)	< 0.0001
E8Bg	0 (0, 0.15)	0.03 (0, 1.11)	0.0177	0 (0, 0.26)	0.0967
	24 (5.3)	10 (32.3)	< 0.0001	9 (7.9)	0.269
R29g	0 (0, 0.002)	0 (0, 0.43)	0.0424	0 (0, 0.24)	0.2341
	13 (2.8)	5 (16.2)	< 0.0001	3 (2.6)	0.913
3D7g	0 (0, 0.33)	0.01 (0, 0.37)	0.4718	0 (0, 0.42)	0.8673
	36 (7.9)	4 (12.9)	0.324	10 (8.9)	0.734

Significant p value in italic format

^aFor each antigen represented, row 1: median antibody level (interquartile range); row 2: number of seropositive children (%)

^bp value calculated by Mann–Whitney test or Chi squared test for antibody level or seropositivity, respectively

^cMerozoite surface protein 1

^dMerozoite surface protein 2

^eErythrocyte binding antigen 175

^fReticulocyte binding protein homologue 2A

^gVariant surface antigen antibody responses