Table 1 Socio-demographic comparison between scrub typhus cases and controls, Khanh Hoa, August 2018–March 2020

Age group, years

  ≤ 30

12 (27.3%)

45 (29.6%)

–

–

 31–40

11 (25.0%)

27 (17.8%)

0.29

1.9 (0.6–6.4)

 41–50

13 (29.6%)

47 (30.9%)

0.78

1.2 (0.3–5.3)

  ≥ 51

8 (18.2%)

33 (21.7%)

0.98

1.0 (0.2–6.5)

Sex

 Male

27 (61.4%)

65 (42.8%)

0.05

2.0 (1.0–4.1)

 Female

17 (38.6%)

87 (57.2%)

–

–

Ethical group

 Kinh

38 (86.4%)

125 (82.8%)

0.35

1.8 (0.6–5.9)

 Others

6 (13.6%)

26 (17.2%)

–

–

Education

 Illiteracy

2 (4.7%)

10 (6.6%)

–

–

 Primary school

16 (37.2%)

35 (23.0%)

0.34

2.3 (0.4–12.4)

 Secondary school

11 (25.6%)

60 (39.5%)

0.87

0.9 (0.2–4.7)

 High school

11 (25.6%)

30 (19.7%)

0.56

1.6 (0.3–8.7)

 University and higher

3 (7.0%)

17 (11.2%)

0.69

0.7 (0.1–5.0)

Occupation

 Not related field/sea/sand

16 (36.4%)

78 (51.3%)

–

–

 Farmer

4 (9.1%)

32 (21.1%)

0.17

0.6 (0.4–2.1)

 Gardening, growing vegetables

4 (9.1%)

6 (4.0%)

0.11

3.5 (0.8–16.0)

 Working in forests/ mountain fields

12 (27.3%)

17 (11.2%)

0.006

4.5 (1.5–12.9)

 Others

8 (18.8%)

19 (12.5%)

0.24

1.9 (0.7–5.4)

Number of people living in same household

 1–3 people/household

9 (20.5%)

40 (26.5%)

–

–

 4–5 people/household

22 (50.0%)

75 (49.7%)

0.43

1.4 (0.6–3.5)

  ≥ 6 people/household

13 (29.6%)

36 (23.8%)

0.30

1.7 (0.6–4.8)

History of scrub typhus

 Participants 2 years prior to study

  Yes

4 (9.1%)

2 (1.3%)

0.02

7.3 (1.3–39.9)

  No

40 (90.9%)

150 (98.7%)

–

–

 Family members 2 years prior to study

  Yes

2 (4.7%)

5 (3.3%)

0.64

1.5 (0.3–8.5)

  No

41 (95.4%)

147 (96.7%)

–

–

 Number of years living in same house

   ≤ 1 year

2 (4.6%)

2 (1.3%)

–

–

  2–3 years

2 (4.6%)

6 (4.0%)

0.48

0.4 (0.04–4.6)

   ≥ 4 years

40 (90.9%)

144 (94.7%)

0.22

0.3 (0.04–2.1)