Syracuse, N.Y. — Onondaga County Executive Ryan McMahon warned Monday that coronavirus cases could spiral out of control if residents don’t do more social distancing immediately.

For the first time, McMahon revealed projections from Upstate Medical University showing when COVID-19 cases locally might peak. He posted it on Twitter and talked about it during his Monday news conference.

This is a model done by Upstate Medical University on potential Positive Covid 19 cases for @OnondagaCounty. Do we want to be brown curve or the yellow curve? 50% social distancing gets us to yellow. We want to be at yellow. pic.twitter.com/0mUWga9IUI — Ryan McMahon (@CHM_McMahon) April 5, 2020

The projections show that everything depends on how well we change our social habits in the next couple of weeks, he said.

From here, we could follow a grim projection that forecasts more than 5,000 infections at once countywide by mid-June. That’s if we’re only mediocre at social distancing (the brown curve, defined as “38 percent distancing” on the chart).

On the other hand, we could follow a much better trajectory, totaling 2,500 infections at once and a significantly lower peak in mid-August. That’s if we do well with social distancing (the yellow curve, defined as “50 percent distancing” on the chart).

Besides saving lives, the second trajectory would be manageable in the hospitals and provide a good argument to reopening the economy sooner rather than later, McMahon said.

It’s unclear how many total people would need to be hospitalized or die under the projections, though the graphic suggests a 2 percent mortality rate among total infections. (The lines on the chart only represent infections on that date; the total number of infections — including recoveries and deaths — would be much greater.)

Gov. Andrew Cuomo earlier extended social-distancing orders until late April. And McMahon has banned parties, closed golf courses and implemented a voluntary “stay-at-home” program, in which people only run essential errands every other day.

As far as the Upstate graphic goes, the percentages aren’t as important as the fact that we need to do better than we are now, he said.

“Even if they’re wrong a little bit, we know if we do better social distancing, we’re going to do better with the virus,” McMahon said.

The bad news? Cell phone tracking data, cited by McMahon, shows that we’ve actually increased our movements in the past week, even as officials at all levels have urged residents to stay put inside their homes.

“We haven’t been doing better (with social distancing) last week, compared to the week before, so let’s turn it around,” McMahon said. “I’m pleading with you ... and the only way we’re going to do it is, the public’s gotta buy in.”

He cited data from Unacast, an online group that publicly rates how well residents of certain areas are doing at reducing overall movement during the pandemic.

Our county’s grade from Unacast went from a "B" on March 28 — reducing movements by 40 to 55 percent — to a “C-” now, reducing movements by only 25 to 40 percent, McMahon noted.

A screenshot of the social distancing grade that Unacast has given Onondaga County. It was cited by County Executive Ryan McMahon as proof that residents need to do a better job of social distancing.

Unacast says it uses location data — present on almost all mobile devices — to see how much people are moving and whether they’re going to essential locations (like grocery stores) or non-essential locations (like clothing stores). Google and other companies are also studying such data, looking for societal trends, not individual movements.

It’s unclear how the percentages in Unacast’s data correspond to those on the Upstate map. McMahon simply noted that our social distancing has gotten worse in recent days. The worse our social distancing, the higher the number of infections and deaths forecast by the Upstate projection, he noted.

So far, the county has seen five deaths from the coronavirus — including four in the past week. That number is expected to grow as some infected people grow sicker, need critical care and lose their battle with the virus.

“This is bigger than all of us right now,” McMahon said, in urging people to remain home for the next two weeks. “I’m just begging you, this is bigger than all of us.”

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