| Vaccine | Ty21a control | Ty21a(pUreA/B) | |||||||||||
| Volunteer | 2 | 6 | 7 | 12 | 4 | 8* | 10 | 13* | 15 | 5* | 16 | 18 | 20 |
| Test† | |||||||||||||
| H pylori culture | – | – | + | + | + | – | + | – | + | – | – | – | – |
| RUT | + | – | + | + | + | – | + | – | + | – | – | – | + |
| UBT | + | – | + | + | + | + | + | + | + | – | – | – | – |
| H pylori histology | + | + | – | + | + | + | + | + | + | – | – | – | – |
| Score‡ | 3 | 1 | 3 | 4 | 4 | 2 | 4 | 2 | 4 | 0 | 0 | 0 | 1 |
*Volunteers receiving the Ty21a(pureA/B) vaccine containing plasmid pDB3.
†H pylori colonisation was determined by culture of biopsies, RUT on biopsies and Warthin Starry staining of biopsy sections in addition to UBT.
‡Sum of positive tests at 6 weeks and/or 3 months postchallenge; clearing volunteers with a score ⩽2 are marked in bold.
RUT, rapid urease test; UBT, [13C]urea breath test.