An individual who is infected with the novel coronavirus has the potential to transmit the disease quickly to about half of all household members, according to a new study by the U.S. Centers for Disease Control and Prevention.

The agency added that the person suspected of having coronavirus should be isolated immediately before getting tested and that all members of the household should wear face masks or coverings at all times in common spaces.

“Because prompt isolation of persons with COVID-19 can reduce household transmission, persons who suspect that they might have COVID-19 should isolate, stay at home, and use a separate bedroom and bathroom if feasible,” the researchers wrote.

For the study, the researchers followed 101 people initially infected with coronavirus in Nashville, Tennessee, and Marshfield, Wisconsin, between April and September. What the team found was that 53 percent of those who lived with someone who carried the virus eventually became infected within a week.

Moreover, roughly 75 percent of these secondary infections occurred within five days of the initial patient exhibiting his or her first symptoms.

“Substantial transmission occurred whether the index patient was an adult or a child,” the researchers noted, adding that previous related studies had reported only 20- to 40-percent infection rates.

“Many reported no symptoms throughout seven days of follow-up, underscoring the potential for transmission from asymptomatic secondary contacts and the importance of quarantine.”

Dr. Beth Thielen, assistant professor at the University of Minnesota Medical School and pediatric infectious-disease physician with M Health Fairview, told The National Interest that “these are some of the highest quality data I have seen on this topic because this was conducted as a prospective study with intensive sampling, which increases the chances that all secondary cases were identified. Earlier studies may have yielded lower rates because they focused testing on symptomatic individuals.”

As for the fast-approaching holiday season in which large family gatherings may play a sizeable role in further spreading the virus, Thielen added: “People need to assess their individual circumstances and carefully weigh the risks and benefits of gathering and assume that they are incurring some risk of infection by gathering with people outside their household. Individuals with higher risk of severe disease, such as older individuals and those with underlying health conditions, may weigh these risks and benefits differently from younger otherwise healthy people, who are at lower risk of severe disease.”

Dr. Jorge Salinas, a hospital epidemiologist at the University of Iowa Hospitals and Clinics, is recommending that individuals should avoid gathering in groups larger than ten people.

However, “even that can be pushing the boundaries—while wearing a mask. For this reason, spending the holidays with extended family members may not be a safe option for many this year,” he told TNI.

“The thing we need to ask ourselves, even if we feel healthy and protected: Are we okay passing this to grandma and grandpa? Would we be okay if we gave it to mom and dad? Is it worth that level of risk?”

Salinas added that if people feel that they must attend the holiday gatherings, they can still take proactive measures that could help keep everyone safe.

“Wear a mask except when you’re eating, and practice social distancing,” he said. “Don’t gather around the same table unless you can really put some distance between you, which can be difficult. Don’t serve foods buffet-style with everyone touching the same utensils or reaching into the same breadbasket.”

But “the best and safest thing to do to protect yourself and your family is to stay home,” he added.

Ethen Kim Lieser is a Minneapolis-based Science and Tech Editor who has held posts at Google, The Korea Herald, Lincoln Journal Star, AsianWeek, and Arirang TV. Follow or contact him on LinkedIn.

Image: An ambulance worker wearing safety equipment and mask against the coronavirus disease (COVID-19) goes through a disinfection routine.