UMass model sees cases continuing to climb into early January

A person receiving a coronavirus test recently at a site in ChelseaJessica Rinaldi/Globe Staff

The number of coronavirus cases reported in Massachusetts will continue to rise, then stabilize around early January, a model from the University of Massachusetts Amherst suggests.

The model says there were a total of 33,708 confirmed and probable cases in the week ending last Saturday. Case numbers are expected to rise in the following three weeks, reaching a weekly total of 41,954 on Saturday, Jan. 2, and remaining around 41,524 for the week ending Saturday, Jan. 9.

Researchers noted that the numbers could range higher or lower, with the case numbers for the Jan. 9 week coming in as low as 31,365 or as high as 46,358.

The UMass model predicts cases will increase in Mass. for several weeks then flatten.Reich Lab/UMass (Custom credit)

The projection comes from a lab headed by UMass Amherst associate professor Nicholas Reich that collects various models and develops a combined, or ensemble, forecast that is intended to reflect their collective wisdom. Reich’s lab only creates the forecast for a four-week window ahead because researchers believe forecasts aren’t reliable enough after that.

Whether the early January lull in cases foreseen by the model will be the beginning of a downward trend is uncertain, but one of the scenarios projected by the closely watched model from the University of Washington’s Institute for Health Metrics and Evaluation calls for Massaschusetts cases to begin to decline around mid-January.

The state has been undergoing a dismaying second surge. The UMass model this fall has tended to underestimate the strength of the virus’s comeback.

The forecast also predicts the state’s confirmed and probable death toll could rise to 13,120 by Jan. 9, though the numbers could range between 12,772 and 13,705.

And it predicts 542 people will die from confirmed and probable cases in the week ending Jan. 9, an average of about 77 people a day. That weekly number could range from 403 to 688, researchers noted.

Reich’s lab posts its national- and state-level data every week 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 feeds the data it has collected and its ensemble forecast to the agency, which posts the data on its own website.

The model predicts cases nationally will tick downward slightly in the week of Jan. 9, welcome news as the country struggles to make it through the surge.

But the deaths will keep adding up, according to the model, with around 346,000 confirmed and probable coronavirus deaths by Jan. 9.