Table 4. Open in new tab Factors...

	Retained	Univariable	Multivariable
Randomization Arm	Crossover Vaccination	3628 (95.2)	ref	.0039
	Immediate Vaccination	4012 (96.5)	1.4 (1.1–1.7)
Gender	Male	4748 (94.6)	ref	<.0001	ref	.0056
	Female	2892 (98.1)	3.0 (2.3–4.0)		1.6 (1.2–2.3)
Age (tertiled) (years)	18–27	2491 (93.8)	ref	<.0001	ref	<.0001
	>27–35	2539 (96.3)	1.7 (1.3–2.2)		1.5 (1.2–1.9)
	>35	2610 (97.6)	2.6 (2.0–3.5)		2.2 (1.7–3.0)
Occupation	Nurse^a	2312 (99.0)	ref	<.0001	ref	<.0001
	Doctor	18 (90.0)	0.1 (0.02–0.4)		0.1 (0.02–0.5)
	Pharmacist	39 (100)	>99.9 (<0.01 to >99.9)		>99.9 (<0.01 to >99.9)
	Allied health professional^b	124 (95.4)	0.2 (0.1–0.5)		0.2 (0.1–0.5)
	Community health worker	145 (96.0)	0.2 (0.1–0.6)		0.3 (0.1–0.7)
	Laboratory worker	261 (97.0)	0.3 (0.1–0.7)		0.5 (0.2–1.1)
	Frontline worker^c	3176 (94.3)	0.2 (0.1–0.3)		0.2 (0.2–0.4)
	Surveillance worker	393 (95.9)	0.2 (0.1–0.4)		0.4 (0.2–0.8)
	Not currently working^d	836 (93.6)	0.2 (0.1–0.2)		0.2 (0.1–0.4)
	Other/Not reported	336 (95.7)	0.2 (0.1–0.4)		0.3 (0.2–0.6)
Facility Type	Clinic setting	1536 (94.6)	ref	.0002
	Ebola Facility	2037 (96.2)	1.4 (1.1–2.0)
	Hospital	2921 (96.9)	1.8 (1.3–2.4)
	Other/Not reported	1146 (94.6)	1.0 (0.7–1.4)
Enrollment Site	Western Rural	1655 (95.0)	ref	<.0001	ref	<.0001
	Western Urban	2783 (95.7)	1.2 (0.9–1.6)		0.8 (0.6–1.1)
	Bombali	1117 (98.2)	3.0 (1.8–4.9)		2.2 (1.3–3.6)
	Tonkolili	695 (98.9)	4.6 (2.2–9.6)		3.0 (1.5–6.3)
	Port Loko (Port Loko Town)	768 (93.4)	0.8 (0.5–1.1)		0.7 (0.5–1.0)
	Port Loko (Lunsar)	345 (94.4)	1.0 (0.6–1.6)		0.6 (0.3–1.0)
	Port Loko (Kaffu Bullom)	277 (95.5)	1.1 (0.6–2.1)		0.9 (0.5–1.6)

Retained

Univariable

Multivariable

N (%)

Odds Ratio (95% CI)

Factor-Level
P Value

Odds Ratio (95% CI)

Factor-Level
P Value

Randomization Arm

Crossover Vaccination

3628 (95.2)

ref

.0039

Immediate Vaccination

4012 (96.5)

1.4 (1.1–1.7)

Gender

Male

4748 (94.6)

ref

<.0001

ref

.0056

Female

2892 (98.1)

3.0 (2.3–4.0)

1.6 (1.2–2.3)

Age (tertiled) (years)

18–27

2491 (93.8)

ref

<.0001

ref

<.0001

>27–35

2539 (96.3)

1.7 (1.3–2.2)

1.5 (1.2–1.9)

>35

2610 (97.6)

2.6 (2.0–3.5)

2.2 (1.7–3.0)

Occupation

Nurse^a

2312 (99.0)

ref

<.0001

ref

<.0001

Doctor

18 (90.0)

0.1 (0.02–0.4)

0.1 (0.02–0.5)

Pharmacist

39 (100)

>99.9 (<0.01 to >99.9)

Allied health professional^b

124 (95.4)

0.2 (0.1–0.5)

Community health worker

145 (96.0)

0.2 (0.1–0.6)

0.3 (0.1–0.7)

Laboratory worker

261 (97.0)

0.3 (0.1–0.7)

0.5 (0.2–1.1)

Frontline worker^c

3176 (94.3)

0.2 (0.1–0.3)

0.2 (0.2–0.4)

Surveillance worker

393 (95.9)

0.2 (0.1–0.4)

0.4 (0.2–0.8)

Not currently working^d

836 (93.6)

0.2 (0.1–0.2)

0.2 (0.1–0.4)

Other/Not reported

336 (95.7)

0.2 (0.1–0.4)

0.3 (0.2–0.6)

Facility Type

Clinic setting

1536 (94.6)

ref

.0002

Ebola Facility

2037 (96.2)

1.4 (1.1–2.0)

Hospital

2921 (96.9)

1.8 (1.3–2.4)

Other/Not reported

1146 (94.6)

1.0 (0.7–1.4)

Enrollment Site

Western Rural

1655 (95.0)

ref

<.0001

ref

<.0001

Western Urban

2783 (95.7)

1.2 (0.9–1.6)

0.8 (0.6–1.1)

Bombali

1117 (98.2)

3.0 (1.8–4.9)

2.2 (1.3–3.6)

Tonkolili

695 (98.9)

4.6 (2.2–9.6)

3.0 (1.5–6.3)

Port Loko (Port Loko Town)

768 (93.4)

0.8 (0.5–1.1)

0.7 (0.5–1.0)

Port Loko (Lunsar)

345 (94.4)

1.0 (0.6–1.6)

0.6 (0.3–1.0)

Port Loko (Kaffu Bullom)

277 (95.5)

1.1 (0.6–2.1)

0.9 (0.5–1.6)

	Retained	Univariable	Multivariable
Randomization Arm	Crossover Vaccination	3628 (95.2)	ref	.0039
	Immediate Vaccination	4012 (96.5)	1.4 (1.1–1.7)
Gender	Male	4748 (94.6)	ref	<.0001	ref	.0056
	Female	2892 (98.1)	3.0 (2.3–4.0)		1.6 (1.2–2.3)
Age (tertiled) (years)	18–27	2491 (93.8)	ref	<.0001	ref	<.0001
	>27–35	2539 (96.3)	1.7 (1.3–2.2)		1.5 (1.2–1.9)
	>35	2610 (97.6)	2.6 (2.0–3.5)		2.2 (1.7–3.0)
Occupation	Nurse^a	2312 (99.0)	ref	<.0001	ref	<.0001
	Doctor	18 (90.0)	0.1 (0.02–0.4)		0.1 (0.02–0.5)
	Pharmacist	39 (100)	>99.9 (<0.01 to >99.9)		>99.9 (<0.01 to >99.9)
	Allied health professional^b	124 (95.4)	0.2 (0.1–0.5)		0.2 (0.1–0.5)
	Community health worker	145 (96.0)	0.2 (0.1–0.6)		0.3 (0.1–0.7)
	Laboratory worker	261 (97.0)	0.3 (0.1–0.7)		0.5 (0.2–1.1)
	Frontline worker^c	3176 (94.3)	0.2 (0.1–0.3)		0.2 (0.2–0.4)
	Surveillance worker	393 (95.9)	0.2 (0.1–0.4)		0.4 (0.2–0.8)
	Not currently working^d	836 (93.6)	0.2 (0.1–0.2)		0.2 (0.1–0.4)
	Other/Not reported	336 (95.7)	0.2 (0.1–0.4)		0.3 (0.2–0.6)
Facility Type	Clinic setting	1536 (94.6)	ref	.0002
	Ebola Facility	2037 (96.2)	1.4 (1.1–2.0)
	Hospital	2921 (96.9)	1.8 (1.3–2.4)
	Other/Not reported	1146 (94.6)	1.0 (0.7–1.4)
Enrollment Site	Western Rural	1655 (95.0)	ref	<.0001	ref	<.0001
	Western Urban	2783 (95.7)	1.2 (0.9–1.6)		0.8 (0.6–1.1)
	Bombali	1117 (98.2)	3.0 (1.8–4.9)		2.2 (1.3–3.6)
	Tonkolili	695 (98.9)	4.6 (2.2–9.6)		3.0 (1.5–6.3)
	Port Loko (Port Loko Town)	768 (93.4)	0.8 (0.5–1.1)		0.7 (0.5–1.0)
	Port Loko (Lunsar)	345 (94.4)	1.0 (0.6–1.6)		0.6 (0.3–1.0)
	Port Loko (Kaffu Bullom)	277 (95.5)	1.1 (0.6–2.1)		0.9 (0.5–1.6)

Table 4.

Open in new tab

Factors Associated With Postvaccination Retention Among Vaccinated Participants, STRIVE (n = 7979)

		Retained	Univariable		Multivariable
		N (%)	Odds Ratio (95% CI)	Factor-Level P Value	Odds Ratio (95% CI)	Factor-Level P Value
Randomization Arm	Crossover Vaccination	3628 (95.2)	ref	.0039
	Immediate Vaccination	4012 (96.5)	1.4 (1.1–1.7)
Gender	Male	4748 (94.6)	ref	<.0001	ref	.0056
	Female	2892 (98.1)	3.0 (2.3–4.0)		1.6 (1.2–2.3)
Age (tertiled) (years)	18–27	2491 (93.8)	ref	<.0001	ref	<.0001
	>27–35	2539 (96.3)	1.7 (1.3–2.2)		1.5 (1.2–1.9)
	>35	2610 (97.6)	2.6 (2.0–3.5)		2.2 (1.7–3.0)
Occupation	Nurse^a	2312 (99.0)	ref	<.0001	ref	<.0001
	Doctor	18 (90.0)	0.1 (0.02–0.4)		0.1 (0.02–0.5)
	Pharmacist	39 (100)	>99.9 (<0.01 to >99.9)		>99.9 (<0.01 to >99.9)
	Allied health professional^b	124 (95.4)	0.2 (0.1–0.5)		0.2 (0.1–0.5)
	Community health worker	145 (96.0)	0.2 (0.1–0.6)		0.3 (0.1–0.7)
	Laboratory worker	261 (97.0)	0.3 (0.1–0.7)		0.5 (0.2–1.1)
	Frontline worker^c	3176 (94.3)	0.2 (0.1–0.3)		0.2 (0.2–0.4)
	Surveillance worker	393 (95.9)	0.2 (0.1–0.4)		0.4 (0.2–0.8)
	Not currently working^d	836 (93.6)	0.2 (0.1–0.2)		0.2 (0.1–0.4)
	Other/Not reported	336 (95.7)	0.2 (0.1–0.4)		0.3 (0.2–0.6)
Facility Type	Clinic setting	1536 (94.6)	ref	.0002
	Ebola Facility	2037 (96.2)	1.4 (1.1–2.0)
	Hospital	2921 (96.9)	1.8 (1.3–2.4)
	Other/Not reported	1146 (94.6)	1.0 (0.7–1.4)
Enrollment Site	Western Rural	1655 (95.0)	ref	<.0001	ref	<.0001
	Western Urban	2783 (95.7)	1.2 (0.9–1.6)		0.8 (0.6–1.1)
	Bombali	1117 (98.2)	3.0 (1.8–4.9)		2.2 (1.3–3.6)
	Tonkolili	695 (98.9)	4.6 (2.2–9.6)		3.0 (1.5–6.3)
	Port Loko (Port Loko Town)	768 (93.4)	0.8 (0.5–1.1)		0.7 (0.5–1.0)
	Port Loko (Lunsar)	345 (94.4)	1.0 (0.6–1.6)		0.6 (0.3–1.0)
	Port Loko (Kaffu Bullom)	277 (95.5)	1.1 (0.6–2.1)		0.9 (0.5–1.6)

		Retained	Univariable		Multivariable
		N (%)	Odds Ratio (95% CI)	Factor-Level P Value	Odds Ratio (95% CI)	Factor-Level P Value
Randomization Arm	Crossover Vaccination	3628 (95.2)	ref	.0039
	Immediate Vaccination	4012 (96.5)	1.4 (1.1–1.7)
Gender	Male	4748 (94.6)	ref	<.0001	ref	.0056
	Female	2892 (98.1)	3.0 (2.3–4.0)		1.6 (1.2–2.3)
Age (tertiled) (years)	18–27	2491 (93.8)	ref	<.0001	ref	<.0001
	>27–35	2539 (96.3)	1.7 (1.3–2.2)		1.5 (1.2–1.9)
	>35	2610 (97.6)	2.6 (2.0–3.5)		2.2 (1.7–3.0)
Occupation	Nurse^a	2312 (99.0)	ref	<.0001	ref	<.0001
	Doctor	18 (90.0)	0.1 (0.02–0.4)		0.1 (0.02–0.5)
	Pharmacist	39 (100)	>99.9 (<0.01 to >99.9)		>99.9 (<0.01 to >99.9)
	Allied health professional^b	124 (95.4)	0.2 (0.1–0.5)		0.2 (0.1–0.5)
	Community health worker	145 (96.0)	0.2 (0.1–0.6)		0.3 (0.1–0.7)
	Laboratory worker	261 (97.0)	0.3 (0.1–0.7)		0.5 (0.2–1.1)
	Frontline worker^c	3176 (94.3)	0.2 (0.1–0.3)		0.2 (0.2–0.4)
	Surveillance worker	393 (95.9)	0.2 (0.1–0.4)		0.4 (0.2–0.8)
	Not currently working^d	836 (93.6)	0.2 (0.1–0.2)		0.2 (0.1–0.4)
	Other/Not reported	336 (95.7)	0.2 (0.1–0.4)		0.3 (0.2–0.6)
Facility Type	Clinic setting	1536 (94.6)	ref	.0002
	Ebola Facility	2037 (96.2)	1.4 (1.1–2.0)
	Hospital	2921 (96.9)	1.8 (1.3–2.4)
	Other/Not reported	1146 (94.6)	1.0 (0.7–1.4)
Enrollment Site	Western Rural	1655 (95.0)	ref	<.0001	ref	<.0001
	Western Urban	2783 (95.7)	1.2 (0.9–1.6)		0.8 (0.6–1.1)
	Bombali	1117 (98.2)	3.0 (1.8–4.9)		2.2 (1.3–3.6)
	Tonkolili	695 (98.9)	4.6 (2.2–9.6)		3.0 (1.5–6.3)
	Port Loko (Port Loko Town)	768 (93.4)	0.8 (0.5–1.1)		0.7 (0.5–1.0)
	Port Loko (Lunsar)	345 (94.4)	1.0 (0.6–1.6)		0.6 (0.3–1.0)
	Port Loko (Kaffu Bullom)	277 (95.5)	1.1 (0.6–2.1)		0.9 (0.5–1.6)

Abbreviations: CI, confidence interval; ref, reference category; STRIVE, Sierra Leone Trial to Introduce a Vaccine Against Ebola.

^aIncludes nurse, midwife, community health nurse, nursing aide, maternal-child health aide, nursing student, and vaccinator.

^bIncludes pharmacist, dentist, medical counselor, nutritionist, and physiotherapist.

^cIncludes contact tracers, ambulance crew, burial workers, cleaners, and swabbers (persons taking post mortem skin/mucosal swabs for Ebola testing).

^dCurrent occupation information was updated for deferred crossover participants during the crossover period. Many were no longer working as the Ebola outbreak subsided, and Ebola response jobs ended. Crossover participants were offered vaccination regardless of work status.

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