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Table 1 Participant characteristics by season of vaccination

From: Seasonal modulation of antibody response to diphtheria-tetanus-pertussis vaccination in infants: a cohort study in rural Gambia

  Season of vaccination (N = 710)a
Dry/Harvest season
(Nov − May) (n = 486)
Rainy/Hungry season
(Jun − Oct) (n = 224)
p-value
Maternal variables
Enrolment visit
  Visit season, n (%): Dry 198 (40.7) 171 (76.3) < 0.001
  Gestational age (weeks) 13.8 ± 3.2 13.8 ± 3.7 0.971
  Age (years) 30.1 ± 6.8 30.5 ± 6.7 0.433
  Parity (n) 4.1 ± 2.7 4.3 ± 2.7 0.358
  Formal education, n (%) 128 (26.3) 33 (14.7) 0.001
  Hb (g/dL) 11.3 ± 1.4 11.6 ± 1.4 0.012
  Anaemia, n (%)b 190 (39.1) 68 (30.4) 0.024
  BMI (kg/m2) 21.1 ± 3.4 21.2 ± 3.7 0.674
  Underweight (BMI < 18.5), n (%) 57 (11.8) 27 (12.2) 0.898
  Supplement groups, n (%)
   FeFol (control) 25.7 (125) 23.7 (53) 0.949
   MMN 25.1 (122) 25.5 (57)
   PE 23.7 (115) 24.6 (55)
   PE + MMN 25.5 (124) 26.4 (59)
20 weeks gestation visit
  Visit season, n (%): Dry/harvest 111 (22.8) 224 (100.0) < 0.001
  Hb (g/dL) 10.8 ± 1.1 11.2 ± 1.3 < 0.001
  Anaemia, n (%)b 260 (55.9) 83 (42.1) 0.001
  BMI (kg/m2) 22.0 ± 3.3 22.3 ± 3.4 0.254
  Underweight (BMI < 18.5), n (%) 46 (9.5) 9 (4.1) 0.014
  Weight gain (enrolment─20 weeks) (kg/wk) 0.35 ± 0.35 0.42 ± 0.34 0.009
30 weeks gestation visit
  Visit season, n (%): Dry/harvest 199 (41.0) 179 (79.9) < 0.001
  Hb (g/dL) 10.6 ± 1.3 10.9 ± 1.3 0.002
  Anaemia, n (%)b 264 (59.1) 107 (50.7) 0.044
  BMI (kg/m2) 23.0 ± 3.2 23.5 ± 3.4 0.048
  Underweight (BMI < 18.5), n (%) 11 (2.3) 1 (0.45) 0.080
  Weight gain (20─30 weeks) (kg/wk) 0.30 ± 0.17 0.37 ± 0.16 0.001
Across pregnancy
  Weight gain (enrolment─30 weeks) (kg/wk) 0.31 ± 0.18 0.35 ± 0.15 < 0.001
  GA at delivery (weeks) 40.2 ± 1.4 40.2 ± 1.5 0.639
  Compliance to supplementation (%)c 87.4 ± 14.6 87.4 ± 12.9 0.981
  Morbidity episodes (n)d 5.6 ± 7.2 4.5 ± 5.1 0.057
Infant variables
Birth visit
  Birth season, n (%): Dry 359 (73.9) 84 (37.5) < 0.001
  Sex, n (%): male 255 (52.5) 111 (49.6) 0.470
  Birth weight (kg) 2.99 ± 0.41 3.05 ± 0.38 0.137
  Birth length (cm) 49.54 ± 1.96 49.79 ± 1.90 0.140
  LBWe 41 (9.7) 12 (6.9) 0.276
  SGA, n (%)f 159 (37.8) 51 (29.5) 0.055
8 weeks visit
  WLZ score −0.26 ± 1.2 −0.38 ± 1.1 0.154
12 weeks visit
  Hb (g/dL) 10.9 ± 1.4 10.3 ± 1.3 < 0.001
  Anaemia, n (%)b 31 (7.5) 40 (21.2) < 0.001
  WLZ score −0.27 ± 1.1 − 0.51 ± 1.2 0.011
  Morbidity episodes (n)h 9.9 ± 12.4 8.9 ± 11.6 0.292
  Exclusively breastfed, n (%) 456 (93.8) 207 (92.4) 0.481
24 weeks visit
  Hb (g/dL) 10.5 ± 1.4 10.5 ± 1.1 0.631
  Anaemia, n (%)b 53 (13.4) 25 (14.8) 0.657
  WLZ score −0.47 ± 1.2 −0.52 ± 1.1 0.580
  Morbidity episodes (n)h 23.42 ± 24.5 21.76 ± 21.59 0.384
  Exclusively breastfed, n (%) 257 (52.9) 112 (50.0) 0.475
  1. Abbreviations: BMI Body Mass Index, DTP Diphtheria-tetanus-pertussis, GA Gestational age, Hb Haemoglobin, LBW Low birth weight, SGA Small-for-gestational-age
  2. aValues are means (SD) unless stated otherwise
  3. bAnaemia was defined as a Hb level between 7.0 and 10.9 g/dL (WHO)
  4. cCompliance to supplementation percentage was generated by dividing the number of LNS jars or tablets the women consumed by the number she received and multiplying by 100
  5. dNumber of morbidity episodes between enrolment and delivery
  6. eLBW (low birth weight) was defined using the WHO definition of a birth weight < 2500 g
  7. fSGA (small-for-gestational-age) was defined as a birth weight-for-gestational-age below the 10th percentile INTERGROWTH-21ST for birth weight
  8. gPreterm birth was defined using the WHO definition of birth before 37 weeks of completed gestation
  9. hNumber of days of reported sickness between birth and 12 weeks or 24 weeks