Table 5.3.4.

The protective effect of bacillus Calmette–Guérin (BCG) found in nine major studies⁵⁸

Group studied	Date of commencement	Duration (years)	Age range	Protection (%)
Native North American	1935–38	9–11	0–20 years	80
Chicago, USA	1937–48	12–23	3 months	75
Georgia, USA	1947	20	6–17 years	0
Illinois, USA	1947–48	19–20	Young adults	0
Puerto Rico	1949–51	5–7.5	1–18 years	31
Georgia/Alabama, USA	1950	14	Over 5 years	14
Great Britain	1950–52	15	14–15 years	78
South India (Bangalore)	1950–55	9–14	All ages	30
South India (Madras)	1969–71	7.5a	All ages	0

^a15-year follow-up has revealed some protection amongst those administered BCG as neonates.