[The development of mucosal vaccines].

The live oral polio vaccine was the first mucosal vaccine accepted for general use. Since then, similar vaccines have been developed against typhoid fever, cholera and rotavirus infection, and a nasal vaccine against influenza has recently been registered in the USA. The only non-living mucosal vaccine on the market today is an oral cholera vaccine consisting of inactivated Vibrio cholerae and the B subunit of cholera toxin. Several groups of scientists are at present working on the development of other mucosal vaccines based on inactivated microbes or parts of them. Results from animal trials at the Norwegian Institute of Public Health, suggest that non-living nasal vaccines can provide protective immunity and may be combined with the same types of vaccines for injection. Clinical trials with nasal vaccines consisting of beta-propiolactone inactivated influenza particles, showed that it was possible to achieve serum concentrations of antibodies at levels providing protection against influenza. IgA antibodies, which were formed in nasal secretions, were specifically aimed at influenza and ought to hinder the spread of the disease. By optimizing the immunization regimes so that the immunological memory is better exploited, and by adding adjuvants to the formulations, it is probable that non-living mucosal vaccines can be realistic alternatives to several of the vaccines now given by injection.