This is actually may be the norm, despite what the media says.
"In this meta-analysis of 54 studies with 77 758 participants, the estimated overall household secondary attack rate was 16.6%"
What's even more surprising, is that in households where the person was asymptomatic, the secondary infection rate was 0.7%. If someone iis living in the same household as someone with an asymptomatic infection and only has a 0.7% chance of contracting it, I wonder how much less that rate is when in the general public. This appears to contradict the notion that asymptomatic people are responsible for large amounts of spread.
"Estimated mean household secondary attack rate from symptomatic index cases (18.0%; 95% CI, 14.2%-22.1%) was significantly higher than from asymptomatic or presymptomatic index cases (0.7%; 95% CI, 0%-4.9%; P < .001)"
https://jamanetwork.com/journals/jam...rticle/2774102