TABLE 4.
ASC responses to CFA/I measured following ingestion of fresh or frozen ETEC vaccine strain ACAM2010 or placeboa
| Isotype of response | Vaccine administered | No. of respondersb | Mean ASC/106 PBMCc | Pd |
|---|---|---|---|---|
| IgA | Fresh | 8/18 (44) | 2.6 | 0.33 |
| Frozen | 13/19 (68) | 11.8 | 0.03 | |
| Placebo | 5/16 (31) | 1.0 | NA | |
| IgG | Fresh | 10/18 (56) | 9.0 | 0.24 |
| Frozen | 13/19 (68) | 9.2 | 0.07 | |
| Placebo | 6/16 (38) | 0.8 | NA | |
| IgA or IgG | Fresh | 12/18 (67) | 11.6 | 0.16 |
| Frozen | 15/19 (79) | 21.1 | 0.04 | |
| Placebo | 7/16 (44) | 1.8 | NA |
A positive response in the ASC assay is a ≥2-fold increase over baseline and ≥2 spots/106 PBMC, measured at day 7 following ingestion of a first dose of vaccine or placebo.
Responders/total number of subjects in group (percent); vaccine groups include recipients of highest dose in phase A; the placebo group comprises recipients of placebo before or after a single dose of either vaccine formulation in phase B. (Two additional ACAM2010 recipients in phase B who received a second dose, one fresh and one frozen, responded positively to the second but not the first dose.)
Peak response at day 7 or 10 following either dose of vaccine, calculated as frequency of ASC at peak − frequency of ASC on day of vaccination.
Fisher's exact test comparing the number of responders to each formulation of vaccine with the number of responders to placebo. NA, not applicable.