FALLS CHURCH, Va. – The good news from University of Virginia experts is that efforts to combat the coronavirus thus far indicate that the growth rate for new cases is not just slowing but leveling off almost entirely.
The bad news, though, is that even if those efforts continue successfully for the length of Gov. Ralph Northam's stay-at-home order, which currently expires June 10, the state will see a summer spike in cases that does not peak until August.
Estimation of COVID-19 Impact in Virginia by Jeff Williamson on Scribd
The models released Monday by state officials and the University of Virginia's Biocomplexity Institute provide one more data set for state officials to use as they evaluate measures to combat the virus and how long they should stay in effect.
"We wanted something that could take more of our Virginia-specific actions into account," Gov. Ralph Northam said Monday.
The model produced by the university projects coronavirus cases under five different scenarios - the worst projecting how the virus spreads unmitigated, and the best projecting how the virus spreads if current social distancing efforts stop the growth rate of the virus through June 10.
A middle-ground scenario projects what happens if mitigation efforts slow the growth rate but don't stop it.
Bryan Lewis, a research professor with the University of Virginia, said data so far indicate that social distancing and other mitigation efforts underway in Virginia are essentially stopping the growth rate. That's not to say that new cases aren't occurring, but that new cases are essentially holding steady.
Under the U.Va. model, new cases would increase only slightly from the current average of about 500 new confirmed cases a day through mid-June under the best-case scenario. Unfortunately, cases would then spike significantly, to a peak of about 12,000 new confirmed cases every day in mid-August.
If the virus were to spread unmitigated, on the other hand, new cases would spike to about 30,000 a day in early May and then drop precipitously to nominal levels by the end of June.
The model also looked at hospital capacity. Projections show COVID-19 patients will take up about 80 percent to 120 percent of total beds and every single region in Virginia will exceed capacity at some point. Best-case scenario, that would not happen until mid-July or late August. Worst case, if the coronavirus spreads unmitigated, hospitals would reach capacity in late April to mid-May.
State officials said delaying the spike until August will give hospitals time to increase capacity and officials time to figure out how to avoid that late summer spike.
"People always adapt to ground reality," said Madhav Marathe, a division director at the institute.
The University of Virginia numbers are significantly different from some other models.
A model from the Univeristy of Washington, for instance, measures different outcomes but on the whole paints a much more optimistic scenario than even the best-case scenario in the University of Virginia model. It essentially projects that cases will peak later this month, and that hospitalizations and deaths from the virus will fall to nominal levels by early June. That model assumes social distancing efforts remain in place through the end of May.
Virginia health secretary Daniel Carey said the various models all have different methodologies and strengths and weaknesses.
"This is not a crystal ball," Carey said of the models. "These models change every single day, sometimes subtly and sometimes dramatically."
Lewis also acknowledged the models' limitations. He said they struggle, for example, with how to account for the fact that other coronaviruses, like influenza, have large been seasonal phenomenons that fade away as spring transitions to summer.
Northam said his primary conclusion from the data is that Virginia must stay the course on social distancing for the foreseeable future.
"If we lift the stay-at-home order or social distancing too soon, if we try to rush to get our lives back to normal, the number of cases will spike higher and earlier," Northam said.
For most people, the virus causes mild or moderate symptoms, such as fever and cough that clear up in two to three weeks. For some it can cause more severe illness and be life-threatening.
