TABLE 1

Demographic Characteristics of the Study Population

Cases (N = 156)Controls (N = 595)
Gender, n (%)
    Female73 (47)274 (46)
    Male83 (53)321 (54)
Vaccine refusers, n (%)18 (12)3 (.5)
Age, mean ± SD, y9.4 ± 5.99.3 ± 5.9
Age groups, n (%)
    ≤3 y35 (22)137 (23)
    4–6 y19 (12)74 (12)
    7–9 y14 (9)56 (10)
    10–12 y17 (11)66 (11)
    13–15 y40 (26)147 (25)
    ≥16 y31 (20)115 (19)