While we already knew indoor gatherings are high-risk environments for spreading COVID, a new study conducted by the Centers for Disease Control and Prevention (CDC) shows just how easily you can catch COVID at home when you live with someone who is infected.
To gain a better understanding of household transmission of the coronavirus, the CDC looked at 101 households in Nashville, Tennessee and Marshfield, Wisconsin from April to September. In each of the households there was one "index patient," who are defined as the first members of a household to show COVID symptoms, test positive for the illness, and live with at least one other household member. The 101 index members and 191 people that lived with them were trained to "complete symptom diaries and obtain self-collected specimens, nasal swabs only or nasal swabs and saliva samples, daily for 14 days," the CDC says.
Read on to see how frequently the virus was passed inside the homes of infected patients and other key findings from the study, and for more on curbing the spread, check out This One Thing Is Better at Protecting You From COVID Than Your Mask.
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Infection occurred more than 50 percent of the time overall.
Among all household members enrolled in the study, 102 submitted nasal swabs or saliva specimens that tested positive, for a secondary infection rate of 53 percent overall. The rate was similar for patients who were asked only to submit nasal swab specimens, the CDC found. And for the latest COVID news from Washington D.C., check out The White House Just Warned of a COVID Surge in These 4 States.
The infection rate was high across all age groups.
Prior to this study, the CDC said estimates about household transmission rates varied widely and that there was little data on the rate children transmitted the virus to other members of their household. As it turns out, age was an insignificant factor in how often infected patients passed the virus on to others they lived with.
Index patients younger than 12 had an infection rate of 53 percent, while patients ages 18–49 and patients over age 50 infected others at a rate of 53 percent and 62 percent, respectively. And for clarity on why you may be feeling extra tired right now, This Is How to Tell If Your Fatigue Could Be COVID, Doctors Say.
Transmission almost always occurred within the first week of illness.
In addition to finding that virus transmission occurred frequently, the study also showed that it occurred early on. "Approximately 75 percent of secondary infections were identified within five days of the index patient's illness onset," the CDC said. This, too, was true for both children and adults.
Self-isolation is crucial to prevent transmission within your home.
Based on the study findings, the CDC gave the following guidance: "Persons should self-isolate immediately at the onset of COVID-like symptoms, at the time of testing as a result of a high-risk exposure, or at time of a positive test result, whichever comes first. All household members, including the index case, should wear masks within shared spaces in the household." And for more up-to-date information delivered to your inbox, sign up for our daily newsletter.