Table 3 Disease characteristics of children presenting with acute “influenza A(H3N2) primary infections” or acute “influenza A(H3N2) re-infections”, with primary infections/re-infections determined on the subtype level, by serological influenza virus A(H3N2) IgG status (hemagglutination inhibition assay)
Characteristics of disease | Acute influenza A(H3N2) primary infections N = 78 | Acute influenza A(H3N2) re-infections N = 14 | p-value* |
|---|---|---|---|
Socio-demographic/viral characteristics | |||
Age, in years (median, IQR) | 3.8 (2.2–4.8) | 3.4 (2.8–4.6) | 0.832 |
Underlying chronic condition; n (%) | 13 (16.7) | 0 (0) | 0.206 |
High influenza virus viral load (ct < 25); n (%) | 39 (50.0) | 3 (21.4) | 0.078 |
Viral co-infection; n (%) | 23 (29.5) | 1 (7.1) | 0.104 |
Duration of disease, maximum body temperature | |||
Days with fever + cough/rhinitis (MOM); median (IQR) | 3 (2–5) | 4 (3–5) | 0.626 |
Days with fever; median (IQR) | 3 (4–5) | 4 (3–5) | 0.899 |
Days with cough; median (IQR) | 10 (6–13) | 11 (7–14) | 0.185 |
Days with rhinitis; median (IQR) | 12 (9–14) | 10 (7–13) | 0.896 |
Maximum temperature; median (IQR) | 39.7 (39.0–40.0) | 39.8 (39.0–40.0) | 0.959 |
Duration of disease; median (IQR) | 9 (6–12) | 9 (5–13) | 0.736 |
Complications | |||
Occurrence of complications (AOM or lower respiratory tract complication or febrile seizures); n (%) | 18 (23.1) | 4 (28.6) | 0.736 |
CRP in mg/dl; median (IQR) | 0.7 (0.3–1.7) | 0.7 (0.3–1.8) | 0.707 |
Severity assessment | |||
Physician assessment at practice visit as moderately/severely ill; n (%) | 56 (73.7) | 7 (50.0) | 0.111 |
CARIFS Sum Score at day of practice visit (median, IQR) | 28 (19–38) | 27 (23–32) | 0.744 |
CARIFS Sum Score at day 3 after practice visit (median, IQR) | 18 (10–30) | 16 (4–22) | 0.156 |
CARIFS Sum Score at day 6 after practice visit (median, IQR) | 8 (3–12) | 6 (0–14) | 0.609 |
Healthcare-system related outcomes | |||
Days in bed after practice visit (median, IQR) | 0 (0–1) | 0 (0–2) | 0.928 |
Absenteeism from child care after practice visit, in days (median, IQR) | 5 (3–6) | 4 (3–6) | 0.684 |
Parent workdays lost after practice visit (median, IQR) | 4 (2–5) | 3 (3–4) | 0.155 |
Additional pediatric practice visit(s); n (%) | 23 (29.5) | 3 (21.4) | 0.750 |
Additional specialist/emergency care/hospital visit; n (%) | 3 (3.8) | 1 (7.1) | 0.480 |