Table 4

Reports from The Gambia of infant HBV vaccination efficacy against chronic HBV infection (HBsAg+) at various ages in childhood
Number HBsAg+/number tested (%)
Age (years) Vaccinees Controls % vaccine efficacy (and 95% CI)
Nationwide GHIS cohort, born 1986–90 and surveyed periodically in 1990–2008, vs concurrently born controls
~4 4/720 (0.6) 78/816 ( 9.6) 94% (84–98)
~9 4/675 (0.6) 85/823 (10.3) 95% (84–98)
~15 2/492 (0.4) 51/420 (13.2) 97% (92–99)
~20* 2/255 (0.8) 59/475 (12.4) 94% (76–99)
All ages 12/2142 (0.6) 273/2534 (10.8) 95% (mean)
Keneba village, born 1984–2002 and surveyed in 2003, vs historical controls surveyed in 1984
1-4 0/176 (0.0) 24/236 (10.2)
5–9 2/203 (1.0) 32/205 (15.6)
10–14 0/185 (0.0) 19/135 (14.1)
15+ 3/224 (1.3) 8/47 (17.0)
All ages 5/788 (0.6) 83/623 (13.3) 94% mean**

*Present survey in 2007–08; 3 previous GHIS follow-up surveys took place during 1990–2004 [8,14,15]. Results for Keneba were from a survey in 2003 [13] of vaccinees born 1984–2002 and from a historical survey in 1984 of unvaccinated children.

**Age-specific results are unstable due to small numbers.

Peto et al.

Peto et al. BMC Infectious Diseases 2014 14:7   doi:10.1186/1471-2334-14-7

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