Characteristics of children and their parents before, 3 and 4.5 years after implementation of PCV-7 in the Netherlands.

Note. PCV-7; 7-valent pneumococcal conjugate vaccine. SD; standard deviation. aDefined as more than 4 hours per week with at least 1 child from a different household. bDefined as passive tobacco smoke exposure indoors at least ≥1 cigar or cigarette during ≥5 days/week. cThe presence of symptoms of an upper respiratory tract infection (URTI) and/or acute otitis media (OMA) as defined by evaluation of parents. dDefined as use of oral or intravenous antibiotics within 1 month before sample was taken.