Comparison of study methods: Thompson et al and Fleming et al
| Thompson et al, USA | Fleming et al, England | |
|---|---|---|
| Study period | Nine complete years (July to June) 1990/91—1998/99 | Eleven winters (October to April) 1989/90—1999/00 |
| Age groups | <12 months, 1–4 years, 5–49 years,50–64 years, 65 years and over | 1–12 months, 1–4 years, 5–9 years, 10–14 years, 15 years and over |
| Methods | Logistic regression using virus positivity rates by week as a marker of disease activity | Comparison of influenza and RSV active and inactive weeks defined by clinical and virological parameters |
| Mortality end | Influenza/pneumonia deaths | Deaths from respiratory causes |
| points | Underlying respiratory and circulatory deaths | All cause mortality |
| All cause mortality |