Respiratory infections with fever greater than 38ºC among mothers and infants combined,* by influenza period and vaccine group
| Outcome | No influenza virus circulating (Sept. 2004–Jan. 2005) | Influenza virus circulating (Feb. 2005–Oct. 2005) | ||||
|---|---|---|---|---|---|---|
| Control n = 216 | Influenza n = 206 | p value | Control n = 116 | Influenza n = 116 | p value | |
| Episodes of respiratory illness with fever, no. | 37 | 36 | 73 | 39 | ||
| Person-months | 932 | 914 | 1014 | 1053 | ||
| Incidence/100 person-months (95% CI) | 4.0 (2.8 to 5.5) | 3.9 (2.8 to 5.5) | 7.2 (5.6 to 9.1) | 3.7(2.6 to 5.1) | ||
| Incidence difference (95% CI) | −0.03 (−1.9 to 1.8) | −3.5 (−5.5 to −1.5) | ||||
| Incidence rate ratio (95% CI) | 0.99 (0.63 to 1.57) | > 0.9 | 0.51 (0.4 to 0.8) | 0.0003 | ||
Note: CI = confidence interval.
↵* All mothers and infants with morbidity data included.