Abstract
1. Alcohol-killed and alcohol-preserved typhoid vaccine retains its power of stimulating Vi- and O-antibody formation unimpaired during storage at 1–2° C. for at least 10 years.2. The Vi antibody induced by immunization with the 10-year-old vaccine possesses full ‘functional efficacy’ in passive-immunity tests in mice.3. The expiry date of this type of vaccine can be extended to a period of 10 years, provided the vaccine is kept in cold storage.4. Alcoholized vaccine can serve as ‘standard vaccine’ in any future attempt at standardization of the potency of typhoid vaccine.