Table 3. VE using different case and control definitions in a study of the use of diagnostic assays for rotavirus in children >8 months of age with acute gastroenteritis, 3 New Vaccine Surveillance Network sites (USA), October 2008–October 2009*.
| Definition, no. doses |
No. (%) cases |
No. (%) controls |
% VE (95% CI)† |
|---|---|---|---|
| EIA+ cases and EIA− controls | 128 | 302 | |
| 0 | 98 (77) | 115 (38) | NA |
| 1 | 6 (5) | 15 (5) | 51 (−38 to 83) |
| 2 | 4 (3) | 43 (14) | 90 (70–97) |
| 3 |
20 (16) |
129 (43) |
84 (71–91) |
| EIA+ case and qRT-PCR− controls | 128 | 266 | |
| 0 | 98 (77) | 99 (37) | NA |
| 1 | 6 (5) | 13 (5) | 47 (−53 to 82) |
| 2 | 4 (3) | 40 (15) | 89 (66–96) |
| 3 |
20 (16) |
114 (43) |
83 (68–91) |
| qRT-PCR+ cases and qRT-PCR− controls | 164 | 266 | |
| 0 | 114 (70) | 99 (37) | NA |
| 1 | 8 (5) | 13 (5) | 47 (−38 to 80) |
| 2 | 7 (4) | 40 (15) | 85 (64–94) |
| 3 |
35 (21) |
114 (43) |
75 (58–86) |
| EIA- and qRT-PCR+ cases vs. EIA- and qRT-PCR- controls | 36 | 266 | |
| 0 | 16 (44) | 99 (37) | NA |
| 1 | 2 (6) | 13 (5) | 21 (−309 to 80) |
| 2 | 3 (8) | 40 (15) | 47 (−108 to 87) |
| 3 | 15 (42) | 114 (43) | 14 (−105 to 64) |
*VE, vaccine effectiveness; EIA, enzyme immunoassay; +, positive; −, negative; NA, not applicable; qRT-PCR, semiquantitative reverse transcription PCR. †Controlling for age (in months), month and year of birth, and month of illness onset in the analysis.