TABLE 4.
Correlation coefficient (r) between seroprevalence measured in summer and the difference of influenza incidence rates between one season and the previous one (ΔILI incidence rate), for each influenza A subtype and influenza B lineage, for overall population and by age group.
| Correlation coefficient (r) between seroprevalence and ILI incidence rate (95% CI) | ||||||
|---|---|---|---|---|---|---|
| AH1 | AH3 | B/Vic | B/Vic a B | B/Yam | B/Yam a B | |
| Overall | −0.5 (−0.9, 0.5) | −0.3 (−0.9, 0.6) | −0.5 (−0.9, 0.5) | −0.3 (−0.9, 0.7) | 0.0 (−0.8, 0.8) | −0.1 (−0.8, 0.8) |
| 0–4 | −0.3 (−0.9, 0.7) | 0.6 (−0.4, 0.9) | −0.1 (−0.8, 0.8) | −0.1 (−0.8, 0.8) | 0 (−0.8, 0.8) | −0.2 (−0.9, 0.7) |
| 5–14 | −0.8 (−1, −0.1)* | −0.1 (−0.8, 0.8) | −0.5 (−0.9, 0.5) | −0.2 (−0.9, 0.7) | 0 (−0.8, 0.8) | −0.1 (−0.8, 0.8) |
| 15–64 | −0.7 (−1, 0.3) | −0.3 (−0.9, 0.7) | −0.6 (−0.9, 0.5) | −0.2 (−0.9, 0.7) | 0 (−0.8, 0.8) | −0.1 (−0.8, 0.8) |
| 65+ | −0.4 (−0.9, 0.6) | −0.2 (−0.9, 0.7) | −0.8 (−1, 0.1) | −0.3 (−0.9, 0.7) | −0.1 (−0.8, 0.8) | −0.1 (−0.8, 0.8) |
Note: Correlation coefficient thresholds were defined as follow: weak (r values from 0 to 0.39 or r from 0 to −0.39), moderate (r from 0.40 to 0.59 or r from −0.40 to −0.59), and strong (r from 0.60 to 1 or r from −0.60 to −1).
a
This was considered the ILI incidence rate for influenza B (both lineages).
*
p = 0.004.