To the Editor: In the July 19 issue, Ward et al. discuss the national study of secondary spread of Haemophilus influenzae meningitis among household contacts. They state that the risk of H. influenzae disease in household contacts indicates “a need for effective antimicrobial prophylaxis.” I disagree. First of all, the risk of secondary meningitis is small; it occurred in less than 1 per cent of 1147 households that they investigated. Secondly, the secondary cases, as they admit, could not be definitely ascribed to a causal relation but may have occurred coincidentally. Thirdly, antibiotics are not without disadvantages. Antibiotic prophylaxis on. © 1979, Massachusetts Medical Society. All rights reserved.