SALT LAKE COUNTY — The Wasatch Front’s four big counties, Weber, Davis, Salt Lake and Utah, hold 75 percent of Utah’s population.
Salt Lake County alone has 48 percent of the people on the Wasatch Front.
Still, until the last three weeks, Salt Lake County has had the bulk of all infections in Utah — more than half of all cases.
That just changed, and it changed exactly when you would expect it to if a mask order were to be effective.
Salt Lake County Mayor Jenny Wilson ordered mask wearing to start on June 27.
The CDC says infection leads to symptoms in 4-5 days median with 97 percent of all symptomatic people showing symptoms within 11.5 days.
That means any lingering pre-mandate infections would show up until July 8 or so.
Take a look a the charts below and Salt Lake takes a dramatic dip in infection right around there.
Correlation doesn’t prove causation, and the situation is complex, but if the trend continues we have strong evidence the mandate is making a difference.
Another piece of evidence: Weber, Davis and Utah Counties all continued to set records for new infections in the same week Salt Lake saw its decline.