Editor's Note
This study by researchers at the University of North Carolina School of Medicine, Chapel Hill, finds that household crowding amplifies the spread of COVID-19, potentially contributing to the disproportionate impact on communities of color.
Researchers followed 100 COVID-19-positive patients and 208 additional household members from April to October, 2020. A total of 44% identified as Hispanic or non-white.
The secondary attack rate among household contacts was 32%, and the majority of cases occurred by day 7.
Infected persons in the same household had similar nasopharyngeal viral loads. Households with secondary transmission had index cases with a median viral load that was 1.4 log10 higher than households without transmission and a higher living density (more than 3 persons living in less than 6 rooms).
Minority households were more likely to have a higher living density and risk of infection than white households (51% vs 19%).
The researchers concluded that COVID-19 transmits early and often among household members. Though masking, physical distancing, and quarantining a household may reduce or prevent transmission beyond the household, these strategies are less effective within a household, especially in a setting of high viral load infections and crowded living conditions, the researchers note.
