Influenza predictions using school-type and grade-specific
absences
We compared the performance of different school-types (elementary,
middle, and high school) and grade-specific absences in seasonal models.
Elementary school models had lower relMAEs compared to middle and high
school models across validations (Supplemental Table 6). Given varied
model performance across school types, we also considered one-week
lagged grade-specific all-cause absences in seasonal models to assess
heterogeneity in predictions by grades.
Univariate analyses found K, 1, 2, 3,4th and
5th grade absence models had lower MAEs than
(individual) middle school and high school grade-specific absence
models, particularly in leave 20% of schools’ out validation (Figure
3A). Multivariate grade-specific absence models also had lower MAEs
relative to seasonal models across three cross-validations (Figure 3B).
We observed consistently lower relMAEs for kindergarten-specific
absences (relMAE: 0.91, 0.98. 0.92 in three validations). Overall,
middle and high school grade-specific absence models did not decrease
MAEs relative to seasonal models, although 8, 9, &
10th grade models in leave 20% of weeks out and
6th grade models in leave 20% schools out had lower
MAEs.
We investigated whether absenteeism can be used to create more accurate
predictions of virologically confirmed influenza only in school aged
children, we built models of virologically confirmed influenza only in
those 5-17 years old, rather than of all ages. We found modest
improvements in two of three validations when including absences
compared to not using absences in models that incorporated week of year,
relative humidity and temperature. Predictions were more accurate when
predicting virologically confirmed influenza in children then when
predicting all ages.