Half of new COVID-19 cases are adults under 40, children

WASHINGTON — According to the Washington State Department of Health data, half of the new COVID-19 cases during the week of May 10 were of patients under 40 years old.

The increase in cases goes along with the analysis done by Dr. Judith Malmgren, an epidemiologist affiliated with the University of Washington.

Malmgren looked at eight weeks of data and found as the cases among patients over age 60 declined, the cases of adults under 40 and children increased. She said that is why the number of cases hit a plateau in our state and is not declining.

“We looked to see what was happening, to explain the plateau,” said Malmgren. “I think that’s kind of the big message here. In eight weeks’ time, which is not long, we switched age distribution from old to young, predominantly young.”

As coronavirus spread through Life Care Center of Kirkland and other nursing homes, health departments issued strong warnings to anyone over 60 or with health concerns to stay home.

It worked. The cases for those over 60, declined. Malmgren’s analysis shows it is an increase in sick patients under 40 that made up the difference and are responsible for coronavirus cases hitting a plateau in our state.

The Washington State Department of Health data shows in the week of May 10, 50% of the new COVID-19 cases were patients under 40.

These are symptomatic patients who were tested with at-home kits, drive-thru testing sites and hospitals. And the concern is those under 40 are no longer being as careful, and the same goes for children.

Malmgren said children are a real concern, especially with the added risk of the multisystem inflammatory syndrome, which presents similar to Kawasaki disease. There are four confirmed cases in the state.

Her analysis of the data is being considered in the state’s reopening plan.

“This is such a fast-moving target that modeling really helped us get to the plateau. But going further, we need a more granular level of analysis so we don’t miss something like this,” said Malmgren.

She said the increase in cases for children really needs to be looked at as plans are developed for the children’s return to school. She said the way the data is collected, it’s hard to tell if children are getting sick from their parents or from playing with each other.