1 in 5 with COVID-19 passes it to others in household, data show

Dec. 14 (UPI) -- Nearly one in five people with COVID-19 spreads the virus to other members of the household, according to an analysis published Monday by JAMA Network Open.

Household transmission was significantly higher for those who had symptoms of infection, at 18%, than those who were asymptomatic or had no symptoms, at less than 1%, the data showed.

Spouses account for 38% of those infected with the virus after household exposure, researchers from the University of Florida and the University of Washington said.

"The findings of this study suggest that households are and will continue to be important venues for transmission, even where community transmission is reduced," they wrote.

The researchers analyzed data from 54 studies of household transmission of COVID-19 in several countries, including the United States, China, Italy, Brazil and Spain, which are among those hardest hit by the pandemic.

The included studies had 77,758 participants, 10,426 of whom were infected with the new coronavirus.

The 17% household spread rate researchers found for the virus was higher than that of SARS, at 8%, and Middle Eastern Respiratory Syndrome, or MERS, at 5%, both of which also are coronaviruses.

For COVID-19, 28% of adult household contacts were infected, compared with just under 17% of child household contacts, the researchers said.

At 42%, the secondary infection rate was higher in households with one close contact than it was in those with three or more close contacts, at 23%, they said.

"Households are favorable environments for transmission," the researchers wrote.

"They are what are known as 3Cs environments, as they are closed spaces, where family members may crowd and be in close contact with conversation," they said.