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RESEARCH:
Anthony Hawkridge, Mark Hatherill, Francesca Little, Margaret Ann Goetz, Lew Barker, Hassan Mahomed, Jerald Sadoff, Willem Hanekom, Larry Geiter, Greg Hussey the South African BCG trial team
Efficacy of percutaneous versus intradermal BCG in the prevention of tuberculosis in South African infants: randomised trial
BMJ 2008; 337: a2052 [Abstract] [Full text]
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[Read Rapid Response] Lack of placebo group not a problem
Peter M English   (21 January 2009)

Lack of placebo group not a problem 21 January 2009
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Peter M English,
CCDC
Surrey KT19 9XF

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Re: Lack of placebo group not a problem

 von Reyn and Zumla in their editorial commenting on a paper by Hawkridge et al1 state (referring to a that 'The authors comment that neither route of administration worked "particularly well," but this conclusion cannot be drawn in a study that had no placebo group.'2

This is unduly dismissive. Hawkridge et al quite correctly point out that the fact that placebo controlled trials are not possible means that overall vaccine efficacy cannot be determined. They found that, however, that 3% of vaccine recipients developed "definite or probable" tuberculosis within 2 years of birth, and a further 3% had "possible" tuberculosis. With "over 6% of properly vaccinated infants developing definite, probable, or possible tuberculosis over the two years after birth", it is quite reasonable to state that this demonstrates that the vaccine is "not particularly effective", with or without a control group.

1. von Reyn CF, Zumla AI. BCG vaccination in children. BMJ 2008;337(nov13_1):a2086- (http://www.bmj.com/cgi/content/full/337/nov13_1/a2086).

2. Hawkridge A, Hatherill M, Little F, Goetz MA, Barker L, Mahomed H, et al. Efficacy of percutaneous versus intradermal BCG in the prevention of tuberculosis in South African infants: randomised trial. BMJ 2008;337(nov13_1):a2052- (http://www.bmj.com/cgi/content/abstract/337/nov13_1/a2052).

Competing interests: None declared