Preparation of a dry oral vaccine stabilizes, consists of a live attenuated virus

The subject of the present invention is a method for preparing a dry oral vaccine, composed of a live attenuated virus, the stability of which has been improved compared with what has previously been obtained. Essentially, an aqueous composition containing not only the virus, but also a ballast agent, a thickener and a stabilizer, which are advantageously present at a concentration such that the dry weight of the composition is high, is dried. The drying can advantageously be continued so as to reach a residual moisture content of about 5% to 10%. Thus, the product which is obtained is a vaccine that can be administered orally without prior rehydration.