definition of secondary attack rate.
MUTGR's link:
https://alachuachronicle.com/university-of-florida-researchers-find-no-asymptomatic-spread/
JAMA link:
Household Transmission of SARS-CoV-2
A Systematic Review and Meta-analysis
https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2774102
CDC link:
Lesson 3: Measures of Risk
Section 2: Morbidity Frequency Measures
https://www.cdc.gov/csels/dsepd/ss1978/lesson3/section2.html
Number of cases among contacts of primary cases divided byTotal number of contacts × 100