Table 5. Pandemic (H1N1) 2009 virus infection SAR, by age of patient with virologically confirmed primary case, United Kingdom, 2009*.

Transmission†	No. contacts	No. secondary case-patients	SAR, % (95% CI)
Child to child	148	29	19.6 (13.5–26.9)
Child to adult	318	9	2.8 (1.3–5.3)
Adult to adult	231	13	5.6 (3.0–9.4)
Adult to child	64	11	17.2 (8.9–­28.7)

*SAR, secondary attack rate; CI, confidence interval.
†Primary case-patient to contact.