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Table 1 Baseline characteristics in intervention and control shehias, May 2016. Numbers in brackets represent the range between shehias

From: A cluster randomised controlled trial of two rounds of mass drug administration in Zanzibar, a malaria pre-elimination setting—high coverage and safety, but no significant impact on transmission

 

Intervention

Control

Survey characteristics

 Date of survey

30 April–7 May, 2016

9 May–17 May, 2016

 Number of households registered

2682 (219–453)

3006 (208–644)

 Household participation rate1 (%)

96.1 (91.4–99.5)

92.8 (87.9–95.4)

 Number people registered (all households)

10,944 (926–1821)

12,307 (935–2542)

 Number people in consenting households (N; %2)

10,683; 97.6%

11,813; 96.0%

 Proportion present at time of survey3 (%)

77.2 (64.9–84.6)

74.6% (61.8–82.8)

Household characteristics

 House type

  Temporary (% palm leaf structure)

7.0 (2.9–11.3)

4.1 (0.0–11.6)

  Semi-permanent (% mud and sticks/stones/coral)

24.3 (12.0–50.7)

26.0 (11.4–40.2)

  Permanent (% brick/stone)

68.7 (43.4–84.1)

69.9 (48.2–88.6)

 Households in proximity to breeding site4 (%)

6.8 (1.7–13.6)

5.8 (0.4–18.4)

 Head of households worried about malaria5 (%)

54.0 (44.5–60.3)

59.2 (49.8–69.4)

Participant characteristics

 Median age [interquartile range]

19 [8–35]

19 [8–35]

 Permanent resident of household (%)

98.1 (96.8–98.7)

98.3 (97.6–99.7)

 Percent female (%)

51.5 (49.5–54.2)

51.7 (49.8–55.3)

 Main occupation6

  Farming (%)

37.7 (10.7–54.5)

42.1 (15.4–60.6)

  Fishing (%)

12.3 (0.5–33.2)

12.7 (0.4–30.8)

  Other (%)

27.7 (20.2–36.7)

25.5 (11.6–44.0)

  Unemployed (%)

24.4 (16.6–30.0)

22.9 (15.0–30.2)

 Overnight travel within Zanzibar in last month (%)

3.4 (2.1–5.0)

2.9 (1.1–4.3)

 Overnight travel outside Zanzibar in last month (%)

0.5 (0.0–1.0)

0.6 (0.1–1.2)

 Overnight travel outside Zanzibar in last 6 months (%)

1.4 (0.4–2.8)

1.5 (0.6–2.3)

Vector control coverage

 Households sprayed in the last 12 months (%)

84.7 (64.3–94.2)

85.1 (77.3–93.8)

 Households with at least one mosquito net (%)

85.6 (72.6–97.4)

82.3 (72.0–93.4)

 Households with at least one mosquito net per sleeping space (%)

67.0 (45.5–81.6)

62.6 (54.0–75.3)

 People with access to a bed net7 (%)

74.5 (56.6–90.6)

71.1 (59.1–80.6)

 People who slept under a mosquito net last night (%)

74.6 (53.9–92.0)

70.2 (55.8–79.6)

 Children under five who slept under a mosquito net last night (%)

79.6 (61.5–96.6)

78.8 (62.7–87.4)

Malaria transmission indicators

 Annual parasite index in 2015 (cases/1000 people)

14.4 (11.1–22.4)

12.7 (8.3–32.8)

 Malaria prevalence at baseline (%)

0.8 (0.0–1.6)

2.5 (0.7–4.5)

  1. 1Households consented/households registered
  2. 2People in consenting households/people registered
  3. 3People present/people registered in consenting households
  4. 4Within 50 m of water assembly
  5. 5Proportion of head of households that are worried that they or a family member will get malaria
  6. 6Occupation only recorded for individuals over the age of 18; other occupations are occupations listed in < 5% of the population
  7. 7This indicator estimates the proportion of the population that could potentially be covered by existing ITNs, assuming that each ITN in a household can be used by two people within that household