Table 2

Risk of post-vaccinial encephalitis (P.V.E.) and death from primary smallpox vaccinations, Stratified by age and study, 1963–1968

Age group and studies

Number vaccinated

P.V.E. No.

Deaths No.

Risk of complication per million (95% C.I.)a

Risk of death per million (95% C.I.)a

Case fatality risk per hundred (95% C.I.)a


Age <1

Neff 1967a

654,000

1

0

1.5

(0.04, 8.5)

0.0

(0.0, 5.6)

0.0

(0.0, 97.5)

Neff 1967b

31,000

1

0

32.3

(0.8, 180)

0.0

(0.0, 119)

0.0

(0.0, 97.5)

Lane 1969

614,000

4

3

6.5

(1.8, 167)

4.9

(1.0, 14.3)

75.0

(19.4, 99.4)

Lane 1970

17,000

3

1

176.5

(36.4, 515)

58.8

(1.5, 328)

33.3

(0.84, 90.6)

Ratner 1970

1

0

0

n/c

n/c

n/c

n/c

n/a

n/a

Neff 1972

32

0

0

n/c

n/c

n/c

n/c

n/a

n/a

Summary

1,316,033

9

4

6.8

(3.1, 13.0)

3.0

(0.8, 7.8)

44.4

(13.7, 78.8)

Age 1 to 4

Neff 1967a

2,973,000

2

1

0.7

(0.08, 2.4)

0.3

(0.008, 1.9)

50.0

(1.3, 98.7)

Neff 1967b

142,000

0

0

0.0

(0.0, 26.0)

0.0

(0.0, 26.0)

n/a

n/a

Lane 1969

2,733,000

6

0

2.2

(0.8, 4.8)

0.0

(0.0, 1.3)

0.0

(0.0, 45.9)

Lane 1970

317,000

3

0

9.5

(2.0, 27.6)

0.0

(0.0, 11.6)

0.0

(0.0, 70.8)

Ratner 1970

68,002

0

0

0.0

(0.0, 54.2)

0.0

(0.0, 54.2)

n/a

n/a

Neff 1972

517

0

0

0.0

(0.0, 7110)

0.0

(0.0, 7110)

n/a

n/a

Summary

6,233,519

11

1

1.8

(0.9, 3.2)

0.2

(0.004, 0.9)

9.1

(0.23, 41.3)

Age 5 to 19

Neff 1967a

2,295,000

8

4

3.5

(1.5, 6.9)

1.7

(0.5, 4.5)

50.0

(15.7, 84.3)

Neff 1967b

110,000

0

0

0.0

(0.0, 33.5)

0.0

(0.0, 33.5)

n/a

n/a

Lane 1969

1,959,000

5

1

2.6

(0.8, 6.0)

0.5

(0.01, 2.8)

20.0

(0.50, 71.6)

Lane 1970

229,000

2

0

8.7

(1.1, 31.5)

0.0

(0.0, 16.1)

0.0

(0.0, 84.2)

Ratner 1970b

193,721

1

1

5.2

(0.1, 28.8)

5.2

(0.1, 28.8)

100.0

(2.5, 100)

Summary

4,786,721

16

6

3.3

(1.9, 5.4)

1.2

(0.5, 2.7)

37.5

(15.2, 64.6)

Age 20 +

Neff 1967a

317,000

1

0

3.2

(0.1, 17.6)

0.0

(0.0, 11.6)

0.0

(0.0, 97.5)

Neff 1967b

15,000

0

0

0.0

(0.0, 246)

0.0

(0.0, 246)

n/a

n/a

Lane 1969

288,000

1

0

3.5

(0.1, 19.3)

0.0

(0.0, 12.8)

0.0

(0.0, 97.5)

Lane 1970

33,000

0

0

0.0

(0.0, 112)

0.0

(0.0, 112)

n/a

n/a

Ratner 1970b

107,822

0

0

0.0

(0.0, 34.2)

0.0

(0.0, 34.2)

n/a

n/a

Summary

760,822

2

0

2.6

(0.3, 9.5)

0.0

(0.0, 4.8)

0.0

(0.0, 84.2)

All agesc

Neff 1967a

6,239,000

12

5

1.9

(0.2, 3.4)

0.8

(0.3, 1.9)

41.7

(15.2, 72.3)

Neff 1967b

298,000

1

0

3.4

(0.1, 18.7)

0.0

(0.0, 12.2)

0.0

(0.0, 97.5)

Lane 1969

5,594,000

16

4

2.9

(1.6, 4.6)

0.7

(0.2, 1.8)

25.0

(7.3, 52.4)

Lane 1970

596,000

8

1

13.4

(5.8, 26.4)

1.7

(0.04, 9.3)

12.5

(0.3, 52.6)

Mellin 1970

109,000

0

0

0.0

(0.0, 33.8)

0.0

(0.0, 33.8)

n/a

n/a

Ratner 1970

369,546

1

1

2.7

(0.07, 15.1)

2.7

(0.1, 15.1)

100.0

(2.5, 100)

Neff 1972

549

0

0

0.0

(0.0, 6697)

0.0

(0.0, 6697)

n/a

n/a

Summary

13,206,095

38

11

2.9

(2.0, 3.9)

0.8

(0.4, 1.5)

28.9

(15.4, 45.9)


n/c = not calculated, n/a = not assessable aRisk and confidence intervals not calculated (n/c) for less that 100 vaccinations. Exact confidence intervals based on the binomial distribution. bThe Ratner study age groups, "Age 5 to 14" and "Age 15+", were counted in the Table age groups "Age 5 to 19" and "Age 20+", respectively. cAll ages group may includes subjects whose age was unknown

Aragón et al. BMC Public Health 2003 3:26   doi:10.1186/1471-2458-3-26

Open Data