811 clear that the existence of maternal antibodies does not guarantee protection of the newborn and that the chance of transfer is related neither to maternal titre (see table) nor to the period in the pregnancy when the mother was vaccinated (not shown). Vaccination of children in the first 6 months of life was unsuccessful-only 1 seroconversion in 58 (2x29). Residual antibodies resulting from placental transfer were found frequently until 80 days after birth, but rarely after this time. seems
Requests for reprints should be addressed to A. de A. C., Escola Paulista de Medicina, Rua Botucatu, 720,04023-Sao Paulo, Brazil. REFERENCES 1. Horwitz, A., Peroni, J. Archs intern. Med. 1941, 74, 365. 2. Morbid. Mortal. Rep. (annual supplements 1960-66). U.S. Government
Printing Office. 3. Cook, S. S. Am. J. Hyg. 1936, 23, 172. 4. Maxcy, K. F. Preventive Medicine and Public Health; p. 121. New York, 1956. 5 Sartwell, P. E., Smith, W. M. Am. J. publ. Hlth not Hlth. 1944, 34, 40. 6. Morbid. Mortal. wkly Rep. (annual supplement 1966). U.S. Government Printing Office. 7. Houston, T., Rankin, J. C. Br. med. Bull. 1907, 2, 1414. 8. Kabat, E. A., Miller, C. P., Kaiser, H., Foster, A. Z. J. exp. Med. 1945, 81, 1. 9. Thomas, L., Smith, H. W., Dingle, J. H. J. clin. Invest. 1943, 22, 361. 10. Bradford, W. L. in Textbook of Pediatrics (edited by W. E. Nelson); p. 425. Philadelphia, 1959. 11. Goldschneider, I., Gotschlich, E. C., Artenstein, M. S. J. exp. Med. 1969, 129, 1307. 12. Landy, M., Trapani, R. J., Clark, W. R. Am. J. Hyg. 1955, 62, 54. 13. Takeda, A. K., Taunay, A. E., Scalabrini, L. G. P., Castro, I. O. Revta Inst. Adolfo Lutz, 1974, 34, 127.
The design of a controlled trial to test the hypothesis that the condom protects the user against s.T.D. is easy enough, but practical difficulties diminish the feasibility of such a trial. The prospective investigation described here was designed to test the null hypothesis that invariable and correct use of the condom during sexual intercourse would make no difference to the prevalence of gonorrhoea in a group of such users compared with its prevalence in a group of non-users. The population from which the two groups are drawn is a selected onemales attending a large metropolitan clinic specialising in the diagnosis and treatment of sexually transmitted diseases and any conclusions that may be drawn from the results should take this fact into account. PATIENTS AND METHODS
Male patients attending the department of genito-urinary medicine at St Thomas’ Hospital between lst January and 31st July, 1975, were questioned before examination about their contraceptive practice. In particular, they were asked whether they had used a condom with their recent sexual partners and, whether it had been used correctly. "Correctly" meant that the condom had been used throughout each act of sexual intercourse and that there had been no unprotected genital contact before or after intercourse. There were thus 3 groups of patients-correct users, incorrect users, and nonusers.
For the purposes of the null hypothesis, it was assumed that the groups of condom users formed representative sub-groups of the population attending the clinic. Differences between the various diagnoses in the different groups were assessed by the X2 test. RESULTS
THE CONDOM AND GONORRHŒA DAVID BARLOW
Department of Genito-urinary Medicine, St Thomas’ Hospital, London SE1 7EH
of the condom by male patients attending a clinic specialising in sexually transmitted diseases has been assessed over a period of six months. Condom users were divided into those who used them properly and invariably, and those who did not. In the group studied, correct use of the condom was associated with a significantly lower probability of acquiring gonorrhœa (p
Requests for reprints should be addressed to A. de A. C., Escola Paulista de Medicina, Rua Botucatu, 720,04023-Sao Paulo, Brazil. REFERENCES 1. Horwitz, A., Peroni, J. Archs intern. Med. 1941, 74, 365. 2. Morbid. Mortal. Rep. (annual supplements 1960-66). U.S. Government
Printing Office. 3. Cook, S. S. Am. J. Hyg. 1936, 23, 172. 4. Maxcy, K. F. Preventive Medicine and Public Health; p. 121. New York, 1956. 5 Sartwell, P. E., Smith, W. M. Am. J. publ. Hlth not Hlth. 1944, 34, 40. 6. Morbid. Mortal. wkly Rep. (annual supplement 1966). U.S. Government Printing Office. 7. Houston, T., Rankin, J. C. Br. med. Bull. 1907, 2, 1414. 8. Kabat, E. A., Miller, C. P., Kaiser, H., Foster, A. Z. J. exp. Med. 1945, 81, 1. 9. Thomas, L., Smith, H. W., Dingle, J. H. J. clin. Invest. 1943, 22, 361. 10. Bradford, W. L. in Textbook of Pediatrics (edited by W. E. Nelson); p. 425. Philadelphia, 1959. 11. Goldschneider, I., Gotschlich, E. C., Artenstein, M. S. J. exp. Med. 1969, 129, 1307. 12. Landy, M., Trapani, R. J., Clark, W. R. Am. J. Hyg. 1955, 62, 54. 13. Takeda, A. K., Taunay, A. E., Scalabrini, L. G. P., Castro, I. O. Revta Inst. Adolfo Lutz, 1974, 34, 127.
The design of a controlled trial to test the hypothesis that the condom protects the user against s.T.D. is easy enough, but practical difficulties diminish the feasibility of such a trial. The prospective investigation described here was designed to test the null hypothesis that invariable and correct use of the condom during sexual intercourse would make no difference to the prevalence of gonorrhoea in a group of such users compared with its prevalence in a group of non-users. The population from which the two groups are drawn is a selected onemales attending a large metropolitan clinic specialising in the diagnosis and treatment of sexually transmitted diseases and any conclusions that may be drawn from the results should take this fact into account. PATIENTS AND METHODS
Male patients attending the department of genito-urinary medicine at St Thomas’ Hospital between lst January and 31st July, 1975, were questioned before examination about their contraceptive practice. In particular, they were asked whether they had used a condom with their recent sexual partners and, whether it had been used correctly. "Correctly" meant that the condom had been used throughout each act of sexual intercourse and that there had been no unprotected genital contact before or after intercourse. There were thus 3 groups of patients-correct users, incorrect users, and nonusers.
For the purposes of the null hypothesis, it was assumed that the groups of condom users formed representative sub-groups of the population attending the clinic. Differences between the various diagnoses in the different groups were assessed by the X2 test. RESULTS
THE CONDOM AND GONORRHŒA DAVID BARLOW
Department of Genito-urinary Medicine, St Thomas’ Hospital, London SE1 7EH
of the condom by male patients attending a clinic specialising in sexually transmitted diseases has been assessed over a period of six months. Condom users were divided into those who used them properly and invariably, and those who did not. In the group studied, correct use of the condom was associated with a significantly lower probability of acquiring gonorrhœa (p
