The status of vaccines to meningococcal and gonococcal disease.

Human beings are subject to infection by two species of Neisseria the meningococcus and the gonococcus. Vaccines effective against meningococcal infection are available and have been widely employed. Their effectiveness rests on the ability to induce antibodies which prevent invasion of the blood stream, but they have only minor effect on the mucosal infection in the nasopharynx, namely the carrier state. With the gonococcus it is the mucosal infection of the genitourinary tract which is, in fact, the disease, and hence a successful gonococcal vaccine must be able to prevent this infection as well as its local extension to the adnexa. The surface antigens of the meningococcus and gonococcus have been found to be remarkably homologous, and their biological properties are becoming clearer. The prospects for a gonorrhoea vaccine will be discussed.