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POST 01183E : BCG AND LEPROSY 8 November 2007 ___________________________________ This posting contains two contributions. Devesh Singh from India asks a question about the protective effect of BCG. Thanks to Uli Fruth from WHO/HQ for providing an answer. The Lancet article to which he refers is surprisingly still available on a pay per view basis, even 11 years after publication. We reproduce the summary below, that provides much information, as well as the summary of a meta-analysis of the literature on the topic published in the Lancet Infectious Disease last year. Please send your questions if you have any. ___________________________________ Dear sir I have a book named "Facts for Life", a contribution from Who, Unicef, Unfpa, Undp, Unaids, Wfp, World Bank. In the routine immunization chapter where the immunization shedule is written, under the shedule it says BCG vaccine saves from TB and some of leprosy. My question is how it works on leprosy ? if it works on leprosy also then why it is not writen everywhere. If it is true please give me the reference? regards-- Devesh Singh ---------------------- Protection against leprosy by BCG has been known for a very, very long time. The most convincing recent evidence comes form a large BCG clinical trial in Malawi in the 1980/90ies, the famous Karonga study: (no individual authors named) Randomised controlled trial of single BCG, repeated BCG, or combined BCG and killed Mycobacterium leprae vaccine for prevention of leprosy and tuberculosis in Malawi. Karonga Prevention Trial Group. Lancet 1996 Jul 6; 348(9019):17-24 Truckloads of papers were published on the details of this trial, main authors: Paul Fine, Jorg Ponnighaus, etc Hope this helps Uli Uli Fruth, PhD Initiative for Vaccine Research World Health Organization Geneva, Switzerland ---------------------- The Lancet - Vol. 348, Issue 9019, 6 July 1996, Pages 17-24 Randomised controlled trial of single BCG, repeated BCG, or combined BCG and killed Mycobacterium leprae vaccine for prevention of leprosy and tuberculosis in Malawi Karonga Prevention Trial Group Background Repeat BCG vaccination is standard practice in many countries for prevention of tuberculosis and leprosy, but its effectiveness has not been evaluated. The addition of Mycobacterium leprae antigens to BCG might improve its effectiveness against leprosy. A double-blind, randomised, controlled trial to evaluate both these procedures was carried out in Karonga District, northern Malawi, where a single BCG vaccine administered by routine health services had previously been found to afford greater than 50% protection against leprosy, but no protection against tuberculosis. Methods Between 1986 and 1989, individuals lacking a BCG scar were randomly assigned BCG alone (27904) or BCG plus killed M leprae (38251). Individuals with a BCG scar were randomly allocated placebo (23307), a second BCG (23456), or BCG plus killed M leprae (8102). Incident cases of leprosy and tuberculosis were ascertained over the subsequent 5–9 years. Findings 139 cases of leprosy were identified by May, 1995; 93 of these were diagnostically certain, definitely postvaccination cases. Among scar-positive individuals, a second BCG vaccination gave further protection against leprosy (about 50%) over a first BCG vaccination. The rate ratio for all diagnostically certain, definitely postvaccination cases, all ages, was 0·51 (95% CI 0·25–1·03, p-0·05) for BCG versus placebo. This benefit was apparent in all subgroups, although the greatest effect was among individuals vaccinated below 15 years of age (RR=0 40 [95% CI 0·15–1·01], p=0·05). The addition of killed M leprae did not improve the protection afforded by a primary BCG vaccination. The rate ratio for BCG plus killed M leprae versus BCG alone among scar-negative individuals was 1·06 (0·62–1·82, p=0·82) for all ages, though 0·37 (0·11–1·24, p=0·09) for individuals vaccinated below 15 years of age. 376 cases of postvaccination pulmonary tuberculosis and 31 of glandular tuberculosis were ascertained by May, 1995. The rate of diagnostically certain tuberculosis was higher among scar-positive individuals who had received a second BCG (1·43 [0·88–2·35], p=0·15) than among those who had received placebo and there was no evidence that any of the trial vaccines contributed to protection against pulmonary tuberculosis. Interpretation In a population in which a single BCG vaccination affords 50% or more protection against leprosy, but none against tuberculosis, a second vaccination can add appreciably to the protection against leprosy, without providing any protection against tuberculosis. ----------------------- The Lancet Infectious Diseases 2006; 6:162-170 The role of BCG in prevention of leprosy: a meta-analysis Maninder Singh Setia , Craig Steinmaus , Christine S Ho and Dr George W Rutherford (Salvatore Pablo Lucia Professor and Director) Summary The present meta-analysis investigates the role of BCG—a widely used yet controversial vaccine—in the prevention of leprosy. The electronic databases Medline, Embase, the Cochrane Library, and LILACS were searched to identify studies assessing the protective effect of BCG against leprosy. We included seven experimental studies and 19 observational studies. The experimental studies demonstrated an overall protective effect of 26% (95% CI 14–37%). At 61% (95% CI 51–70%), the observational studies overestimated the protective effect. The age at vaccination did not predict the protective effect of BCG. An additional dose of BCG was more protective in the prevention of leprosy compared with a single dose. An additional dose of BCG may be warranted for contacts of leprosy patients in areas where leprosy continues to be a public-health problem. ______________________________________________________________________________ All members of the TechNet21 e-Forum are invited to send comments on any posting or to use the forum to raise a new discussion or request technical information in relation to immunization services. 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