Table 2.

Summary of Studies Undertaken for the Ty21a Vaccine in Developing Countries

Study (Year)	Formulation	No. Study Subjects	Ages, Years	Follow-up Period	Protective Efficacy for Blood Culture Confirmed Typhoid (95% CIs)	Incidence Rate in Control Group, per 100 000
Alexandria, Egypt (1978–1980)	Liquid given with tablet of NaHCO3	32 388	6–7	36 months	96% (77–99%)	50
Area Occidente, Santiago, Chile (1983–1986)	3 doses of enteric-coated capsules given (1–2 days between doses)	140 000	6–19	36 months 7 years	67% (47–79%) 62%	110
Area Sur Oriente, Santiago, Chile (1986)	3 doses of enteric-coated capsules (1–2 days between doses)	81 321	6–19	3 years	33% (0–57%)	100
	3 doses liquid suspension (1–2 days between doses)			3 years 5 years	77% 78%
Sumatra, Indonesia (1986–1989)	3 doses of enteric-coated capsules (7 days between doses)	20 543	3–44	30 months	42% (23–57%)	810
	3 doses liquid suspension (7 days between doses)				53% (36–66%)

Abbreviation: CI, confidence interval.