Scientist whose coronavirus model is used by CDC warns states may have to close again

A scientist whose coronavirus model is cited by the Centers for Disease Control and Prevention (CDC), warned Tuesday that states may have to close again if cases jump following the easing of guidelines meant to prevent the spread.

Youyang Gu told CNN that states should not rush their reopenings because “by the time you realize what’s happened, it’ll be too late to reverse the decision.”

“It will be at least two to three weeks before we see an increase in the number of infections because it takes time for individuals to infect others and for them to display symptoms,” he said, adding there is a “lag time” between symptoms worsening, getting tested and receiving the results.

The lag time is longer for deaths, which occur on average “around three weeks” after the infection, Gu said, adding that the data shows a “wide range” across the U.S.

Gu, citing recent studies, said if states mandate that all residents wear masks, “the likelihood of a steep increase in infections will decrease.”

“It depends on how states handle it. Some are doing it more carefully than others,” he told CNN. 

Gu pointed to Japan’s second-largest island Hokkaido, which had to shut down again after three weeks of being reopened because of the boost in cases, which he said wasn’t noticeable until after three weeks.

The data researcher said states need to keep the basic reproduction number, or R value, which represents how many people each person with COVID-19 will likely infect on average, below one. An R value below one means the infection rate of the coronavirus will decrease, while a value more than one would mean cases would exponentially increase. 

The coronavirus has infected a confirmed 1.2 million people in the U.S., leading to more than 71,400 deaths, according to data from Johns Hopkins University.  

The Associated Press reported Tuesday that outside of the New York metro area, the coronavirus infection rate is continuing to grow in the U.S., as several states make moves to reopen their economies.