Ineffectiveness of an oral killed typhoid vaccine in a field trial

A field trial was carried out with a vaccine containing 300x10(9) killed S. typhi (strain Ty58) per tablet. A total of 12 564 children aged 1-15 years were given 3 tablets of the vaccine or a placebo at the rate of one tablet on each of 3 consecutive days. The results indicated that the vaccine, in its present form and at this dosage, gives no protection.