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Table 5 Association between age at the time of malaria episode and antibody levels and seroprevalence in 18 months old children

From: The impact of early life exposure to Plasmodium falciparum on the development of naturally acquired immunity to malaria in young Malawian 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
  1. Significant p value in italic format
  2. aFor each antigen represented, row 1: median antibody level (interquartile range); row 2: number of seropositive children (%)
  3. bp value calculated by Mann–Whitney test or Chi squared test for antibody level or seropositivity, respectively
  4. cMerozoite surface protein 1
  5. dMerozoite surface protein 2
  6. eErythrocyte binding antigen 175
  7. fReticulocyte binding protein homologue 2A
  8. gVariant surface antigen antibody responses