Table 2. Participants` experience of working in clinical trials.

		Kenya	Ghana	Burkina Faso	Senegal
Clinical research experience	0 to 2 years	1	4	2	1
	3 to 5 years	2	3	4	2
	6 to 8 years	6	0	5	3
	9 or more years	8	6	5	8
Study phase	Phase I (a or b)	10	3	10	3
	Phase II	12	3	13	4
	Phase III	13	10	13	8
	Phase IV	4	7	9	3
Type of trial	Drug trial	15	8	16	11
	Vaccine trial	14	10	13	9