Mass. reports 873 new coronavirus cases, 76 new fatalities; UMass model predicts death toll will rise over 8,100

A new sign was set up at the gated entrance on One Post Office Square site for construction workers to inform them about health rules during the COVID-19 coronavirus pandemic.David L. Ryan/Globe Staff

Even as the state eases into reopening its economy, public health officials reported Tuesday that the death toll from the coronavirus outbreak had risen by 76 cases to 5,938, and a new forecast from the University of Massachusetts Amherst predicted the toll would rise to more than 8,100 in the next four weeks.

The number of confirmed coronavirus cases climbed by 873 to 87,925. The Department of Public Health also reported 7,741 new tests had been conducted, marking a total of 476,940 in the state.

The state’s percentage of positive tests by date of testing stayed stable at 10 percent for the fourth day in a row.

The seven-day weighted average of positive test rates, a number the state announced Monday was a key metric it is scrutinizing during the reopening process, showed a slight decrease to 9.9 percent on Monday, down from 10.2 percent a day earlier, and has dropped 65 percent since April 15.

Meanwhile, the three-day average of the number of coronavirus patients in the hospital dipped to 2,534 on Monday, down from 2,607 a day earlier. It has dropped 29 percent since April 15.

The number of hospitals using surge capacity also decreased slightly from 14 on Sunday to 13 on Monday, down 38 percent since April 15. The three-day average of COVID-19 deaths also dropped from 98 on Friday to 82 on Saturday, down 46 percent since April 15.

While the announcement of the state’s reopening plan on Monday has given some hope to a cooped-up population, the UMass forecast served as a grim reminder that the pandemic is not over.

Last week, the UMass model predicted 7,700 would be killed by the virus by June 6. The new forecast advances the four-week forecast by one week, raising the number of deaths to 8,106 by June 13.

The numbers come from a lab headed by UMass Amherst associate professor Nicholas Reich that collects various coronavirus pandemic models and develops a combined, or ensemble, forecast that is intended to reflect their collective wisdom. Nine models were used in the ensemble forecast.

Reich’s lab only creates the ensemble forecast for a four-week window because it believes forecasts aren’t reliable enough after that.

The closely-watched University of Washington Institute for Health Metrics and Evaluation model predicts the state will see 8,949 deaths by Aug. 4.

Even those tragic numbers may be low. Experts are concerned that the pandemic may see a possible resurgence as states gradually reopen. They’ve also raised the possibility the official death tally may be an undercount since virus deaths may have gone unnoticed by officials early on.

The latest UMass ensemble update also predicts the United States as a whole will see 113,364 deaths in four weeks, with a 10 percent chance of seeing fewer than about 107,000 and a 10 percent chance of seeing more than 121,000.

“As we move forward into a very uncertain phase of the COVID-19 outbreak, it is vital that we be critical consumers of models. By looking at models from different research groups, we can improve our understanding of the range of possible future outcomes,” Reich said in a statement.

Reich’s lab posts its data at the Reich Lab COVID-19 Forecast Hub. The lab, already an Influenza Forecasting Center of Excellence, collaborates with the US Centers for Disease Control and Prevention on coronavirus predictions.

The lab also feeds the data it’s collected and its ensemble forecast to the agency, which posts the data on its own website. The data is also used to feed the fivethirtyeight.com website. Reich’s lab posts its data at the Reich Lab COVID-19 Forecast Hub.