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Familial secondary attack rate (fSAR) and data volumes for the 2012 and 2013 seasons
| Season | Number of users reporting influenza-like illnesses symptoms | Familial secondary attack rate |
|---|---|---|
| 2012 | 65 422 | 30·5% (SE 1·3%) |
| 2013 | 93 459 | 25·7% (SE 0·8%) |
Standard errors of fSAR estimate were computed using bootstrap sampling with replacement.
