Table 3.

Household Secondary Attack Rates by Index Case Age Group

		Household Secondary Attack Rate, % (95% Confidence Interval)
		By index case age group
Study	Sample Size	Children	Adults	Older adults
Park et al [16] (South Korea)	10 592	16.0 (11.9–20.7)a	10.5 (9.9–11.2)	16.8 (15.1–18.6)b
Xin et al [13] (Qingdao, China)	106	12.5 (5.9–22.4)		29.4 (15.1–47.5)c

Exact binomial confidence intervals were computed for estimates reported without uncertainty.

^a0–19 years.

^b≥60 years.

^c≥55 years.