Understanding COVID-19 spread and secondhand exposure risk

Jana Mathia, Gazette Editor | Jun 11, 20200

WHITMAN COUNTY – Thursday: Al has been sick with a stomach bug for the past week. His buddy Bill comes over to bring soup and visit. Then Bill goes to his sister Cindy’s to talk about taking his son to a family campout.

Friday morning: Bill drops off son Devon with Cindy who takes him and her two kids to Grandpa Ethan’s for a “campout” in the back yard. Al lives with his mother Felicity. Al’s niece Gabby stops by for a quick visit and gives Grandma Felicity a hug, then goes to play at her friend Heidi’s house.

Friday afternoon: Al returns a COVID-19 positive test.

What should each person do now? Who should test or isolate? Al’s household is tested Saturday and Grandma Felicity also tests positive but is asymptomatic; what and how does that change for those involved?

“You have to have a few days for Bill to get sick,” answered Public Health Director Troy Henderson, which puts Cindy, Devon, Ethan and Heidi all in the clear.

“It doesn’t work second level.”

Henderson explained that after someone is exposed to COVID-19, the virus goes through an incubation period before that person can infect others. The incubation period is thought to be two to five days, so “Bill” in the example would need at least two days before he could infect others.

“In all cases you have to have an incubation period,” Henderson said.

Grandma Felicity’s asymptomatic infection lowers the risk of spread to granddaughter Gabby. As the virus is spread through droplets, a person who coughs spews more virus than a person who does not. Henderson noted there is a lower risk of asymptomatic spread, but viral shedding varies from person to person. “Shedding” is the term for how much virus a person gives off.

For both Bill and Felicity, they would need to wait at least two days before being tested. Even an infected person won’t test positive if the virus has not had time to reproduce inside them—the incubation period.

Once Al’s test returns positive, it is up to the health department’s contact tracing team to contact his close contacts at risk of infection, including Bill.

“Other people don’t determine who’s a close contact,” Henderson said. In the example, Al’s boss should not tell people who might have been around him to tell the health department they are close contacts. The incoming calls while the contact tracer is working off the information provided by Al only adds delay. As there is only one contact tracer assigned to each case, it only bogs things down.

“We need to be left alone to do our work. We will be reaching out to those who are close contacts,” said Henderson. “Close contact” is defined as a person within six feet for 15 minutes. Another issue with people calling the health department is the department can not confirm to anyone that Al has COVID-19.

For those concerned they might be a close contact, but are not contacted by the contact tracer, Henderson recommends that person reach out to their medical provider about being tested. They would still need to wait two or three days before being tested for that incubation period to pass.

According to Henderson, the window for the most shedding of virus is believed to be 12 hours before symptoms begin to three days after symptoms have passed. There are a “wide smattering” of symptoms related to COVID-19, he said.