That's almost three times higher than 50 years ago. Finances and caregiving are the driving factors behind multigenerational households, according to the Pew Research Center.
A general increase in mask-wearing has been encouraging, U.S. public health experts say. But too few young people, especially, are social distancing and taking other steps to slow coronavirus' spread.
As college campuses grapple with outbreaks of coronavirus infections, research from the CDC suggests young adults are driving infection rates, putting older, more vulnerable people at risk.