Regarding antileprosy vaccine-an apprehension by Dr. Parkash
This department is for the publication of informal communications that are of interest because they are informative and stimulating, and for the discussion of controversial matters. The mandate of this JOURNAL is to disseminate information relating to leprosy in particular and also other mycobacterial diseases. Dissident comment or interpretation on published research is of course valid, but personality attacks on individuals would seem unnecessary. Political comments, valid or not, also are unwelcome. They might result in interference with the distribution of the JOURNAL and thus interfere with its prime purpose.
To the Editor:
Dr. Parkash should be relieved to learn that his apprehensions ("Antileprosy vaccine-an apprehension"; IJL 1995; 63:572- 573) are largely unfounded. Although he states that "no approved vaccine is available to date for immunoprophylactic use in the population," in fact BCG vaccines are licensed in all nations, are very widely employed (approximately 100 million individuals vaccinated in 1995 alone), and have repeatedly been shown to provide protection against leprosy (1,5,7-14). The fact that BCG vaccines are often considered to be directed against tuberculosis (TB) is irrelevant since studies to date indicate that BCG vaccines are more effective against leprosy than against TB(9,11,15). Dr. Parkash is also concerned that, because lepromatous cases may be selectively anergic to antigens of the leprosy bacillus, and because cell-mediated immune responses are influenced by HLA, "it is worth arguing that probably for (lepromatous leprosy-prone individuals) .. . an antileprosy vaccine may not be successful in providing protective immunity." However, several studies have indicated that BCG protects against multibacillary disease, and studies in Brazil (12), Venezuela (5), Malawi (10), and Indonesia (3) have even indicated greater protection against multibacillary than paucibacillary disease. Such evidence suggests that the anergy expressed by lepromatous cases is determined by nurture as well as by nature, and can be influenced by appropriate antigen exposure. Because of these actions the ongoing worldwide antileprosy (BCG) vaccination program is undoubtedly playing a major role in the global decline of leprosy. That said, it is also very true that BCG's effectiveness appears to vary between populations, and that there are still plenty of problems for those with interests in the immunology of antileprosy vaccines (6). But immunologists would do well to observe the available human data before becoming too pessimistic on the basis of theory alone.
- P.E.M. Fine, V.M.D., Ph.D.
Head, Communicable Disease Epidemiology Unit
London School of Hygiene and Tropical Medicine
Keppel Street
London WC1E 7HT, U.K.
REFERENCES
1. BAGSHAWE, A., SCOTT, G. C., RUSSELL, D. A., WIGLEY, S. C., MERIANOS, A. and BERRY, G. BCG vaccination in leprosy: final results of the trial in Karimui, Papua New Guinea Bull. WHO 67(1989)389-399.
2. BAKER, D. M, NGUYEN-VAN-THAM, J. S. and SMITH, S. J. Protective efficacy of BCG vaccine against leprosy in southern Malawi. Epidemiol. Infect. 111(1993)21-25.
3. BOELENS, J. J., KROSE, R., VAN BEERS, S. and LEVER, P. Protective effect of BCG against leprosy in South Sulawesi, Indonesia. Int. J. Lepr. 63(1995)456-457.
4. CONVIT, J., SAMPSON, C, ZUNIGA, M., SMITH, P. G., PLATA, J., SILVA, J., MOLINA, J., PINARDI, M. E., BLOOM, B. R. and SALGADO, A. Immunoprophylactic trial with combined Mycobacterium leprae/ BCG vaccine against leprosy: preliminary results. Lancet 339(1992)446-450.
5. CONVIT, J., SMITH, P. G., ZUNIGA, M., SAMPSON, C, ULRICH, M., PLATA, J. A., SILVA, J., MOLINA, J. and SALGADO, A. Venezuela: a case-control study. Int. J. Lepr. 61(1993)185-191.
6. FINE, P. E. M. Variation in protection by BCG: implications of and for heterologous immunity. Lancet 346(1995)1339-1345.
7. LWIN, K., SUNDARESAN, T., GYI, M. M., BECHELLI, L. H., TAMONDONG, C, GARBAJOSA, P. G., SANSARRICQ, H. and NOORDEEN, S.K. BCG vaccination of children against leprosy: fourteen-year findings of the trial in Burma. Bull. WHO 63(1985)1069-1078.
8. MULIYIL, J., NELSON, K. E. and DIAMOND, E. L. Effect of BCG on the risk of leprosy in an endemic area: a case-control study. Int. J. Lepr. 59(1991)229-236.
9. OREGE, P. A., FINE, P. E. M., LUCAS, S. B., OBURA, M., OKELO, C. and OKUKU, P. Case-control study of BCG vaccination as a risk factor lor leprosy and tuberculosis in western Kenya. Int. J. Lepr. 61(1994)542-549.
10. PONNIGHAUS, J. M., FINE, P. E. M., STERNE, J. A. C, BLISS, L., WILSON, R. J., MALEMA, S. S. and KILETA, S. Incidence rates of leprosy in Karonga District, northern Malawi: patterns by age, sex BCG status and classification. Int. J. Lepr. 61 10-23.
11. PONNIGHAUS, J. M., FINE, P. E. M., STERNE, J. A. C, WILSON, R. J., MSOSA, E., GRUER, P. J. K., JENKINS, P. A., LUCAS, S. B., LlOMBA, N. G. and BLISS, L. Efficacy of BCG against leprosy and tuberculosis in northern Malawi. Lancet 339(1992)636-639.
12. RODRIGUES, M. L. O., SILVA, S. A., NETO, J. C. A., DE ANDRADE, A.L.S.S., MARTELLI, C.M.T. and ZlCKER, F. Protective effect of intradermal BCG against leprosy: a case-control study in central Brazil. Int. J. Lepr. 60(1992)335-339.
13. STANLEY, S. J., HOWLAND, C, STONE, M. M. and SUTHERLAND, I. BCG vaccination of children against leprsoy in Uganda: final results. J. Hyg. (Camb.) 87(1981) 235-248.
14. THUC, N. V, ABEL, L., LAP, V. D., OBERTI, J. and LAGRANGE, P. Protective effect of BCG against leprosy and its subtypes: a case-control study in southern Vietnam. Int. J. Lepr. 62(1994)532-538.
15. TRIPATHY, S. P. The case for BCG. Ann. Natl. Acad. Med. Sci. 19(1983)11-21.