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Table 2 Gametocyte carriage during follow-up

From: Single low dose primaquine to reduce gametocyte carriage and Plasmodium falciparum transmission after artemether-lumefantrine in children with asymptomatic infection: a randomised, double-blind, placebo-controlled trial

Study Phase A (asymptomatic parasite carriers) AL AL + 0.25 mg/kg PQ AL + 0.40 mg/kg PQ P-values P-values
  % (n/N) % (n/N) % (n/N) (AL vs.AL + 0.25 mg/kg PQ) (AL vs.AL + 0.40 mg/kg PQ)
Gametocyte prevalence by microscopy
 Day 0 17.7 (11/62) 32.0 (24/75) 20.5 (15/73) 0.08 0.83
 Day 2 12.9 (8/62) 16.4 (12/73) 13.7 (10/73) 0.63 1.00
 Day 3 9.8 (6/61) 22.9 (16/70) 14.3 (10/70) 0.06 0.59
 Day 7 6.7 (4/60) 4.2 (3/72) 0.0 (0/71) 0.70 0.04
 Day 10 3.3 (2/60) 1.4 (1/71) 0.0 (0/71) 0.60 0.21
 Day 14 0.0 (0/58) 0.0 (0/73) 0.0 (0/71) - -
Gametocyte prevalence by Pfs25 QT-NASBA
 Day 0 96.4 (54/56) 92.9 (65/70) 85.5 (53/62) 0.46 0.06
 Day 7 46.3 (25/54) 20.3 (14/69) 16.4 (11/67) 0.003 0.001
Study Phase B (patent gametocyte carriers at screening) AL AL + 0.25 mg/kg PQ AL + 0.40 mg/kg PQ P-values P-values
  % (n/N) % (n/N) % (n/N) (AL vs.AL + 0.25 mg/kg PQ) (AL vs.AL + 0.40 mg/kg PQ)
Gametocyte prevalence by microscopy
 Day 0 69.4 (34/49) 55.3 (26/47) 83.3 (40/48) 0.21 0.15
 Day 2 34.7 (17/49) 20.4 (9/44) 28.9 (13/45) 0.17 0.66
 Day 3 28.6 (14/49) 10.9 (5/46) 15.6 (7/45) 0.04 0.15
 Day 7 20.4 (10/49) 6.4 (3/47) 6.7 (3/45) 0.07 0.07
 Day 10 17.4 (8/46) 4.3 (2/47) 0.0 (0/44) 0.05 0.006
 Day 14 13.6 (6/44) 0.0 (0/40) 0.0 (0/38) 0.03 0.03
Gametocyte prevalence by Pfs25 QT-NASBA
 Day 0 95.9 (47/49) 93.7 (45/48) 100.0 (46/46) 0.68 0.50
 Day 7 55.1 (27/49) 20.4 (10/49) 17.0 (8/47) 0.001 <0.001
Only patent gametocyte carriers at enrolment AL AL + 0.25 mg/kg PQ AL + 0.40 mg/kg PQ P-values P-values
  % (n/N) % (n/N) % (n/N) (AL vs.AL + 0.25 mg/kg PQ) (AL vs.AL + 0.40 mg/kg PQ)
Gametocyte prevalence by Pfs25 qRT-PCR
 Day 0 95.6 (43/45) 98.0 (48/49) 98.0 (49/50) 0.60 0.60
 Day 2 93.2 (41/44) 87.5 (42/48) 90.4 (47/52) 0.49 0.72
 Day 3 88.4 (38/43) 75.5 (37/49) 92.2 (48/52) 0.18 0.72
 Day 7 66.7 (28/42) 34.0 (17/50) 27.8 (15/54) 0.003 <0.001
 Day 10 65.8 (27/41) 28.6 (14/49) 20.7 (11/53) 0.001 <0.001
 Day 14 42.5 (17/40) 10.2 (5/49) 16.7 (9/54) 0.001 0.01
  Mean (95 % CI) Mean (95 % CI) Mean (95 % CI)   
AUC gametocyte densities over time (in gametocytes μL-1 days)b 14.7 (5.5 – 24.0) 5.5 (1.1 – 10.0) 5.6 (2.1 – 9.1) - -
Gametocyte clearance time (in days) 19.7 (14.6 – 24.8) 7.7 (6.3 – 9.1) 8.2 (6.7 – 9.6) - -
     P-values P-values
  AL vs. AL + 0.25 mg/kg PQ AL vs. AL + 0.40 mg/kg PQ AL + 0.25 mg/kg PQ vs. AL + 0.40 mg/kg PQ (AL vs.AL + 0.25 mg/kg PQ) (AL vs.AL + 0.40 mg/kg PQ)
Difference in gametocyte clearance time (in days) 12.0 (6.7 – 17.3) 11.5 (6.2 – 16.8) -0.5 (- 2.5 – 1.6) <0.001 <0.001
  1. Gametocyte prevalences, clearance times and area under the curve (AUC) of gametocyte distributions over time are presented. Gametocyte clearance time: the rate with which malaria sexual stage parasites were cleared was estimated for children with patent gametocytes on day 0; qRT-PCR data were used (N = 150; see Additional file 3). Gametocyte prevalences were similar in primaquine study arms throughout the follow-up (all P-values > 0.05), except on day 0 (microscopy-based detection; P = 0.004) during Study Phase B
  2. AL artemether-lumefantrine, PQ primaquine
  3. a50 children from Study Phase A and 100 from Study phase B
  4. bOnly qRT-PCR measurements on days 3, 7, 10 and 14 for children with qRT-PCR data on all these days are included