RAPID CITY, S.D. – Monument Health predicts that the number of COVID-19 cases could grow rapidly in our region over the coming weeks.
West River COVID-19 positives reached 266 on Tuesday, May 26, 2020, with 17 new confirmed cases.
Monument Health’s short-term projections, based on actual data over the past two weeks and used to calculate the expected growth over the next two weeks, show that in 14 days the number of West River positive COVID-19 cases could grow to 776.
The growth factor is known as the doubling rate, a metric which has been studied carefully across the country. The current West River doubling rate is 8 days, calculated as follows: yesterday’s positives were 266 – the span of days from when the number of cases was half that number was 8 days ago on 5/19/2020 when there were 137 positive cases. As the doubling rate gets more aggressive (a lower number), the number of cases will multiply very quickly. The doubling rate is based on confirmed cases. The actual rate could be shorter, because there are community members who are most likely positive, asymptomatic and who have not been tested.
The short-term projections, combined with statewide data to factor in the impact of tourism and summer events in the Black Hills region, produce long-range projections which have estimated that Rapid City Hospital would have 15 COVID-19 patients in the hospital as of today; actually, 30 COVID-19 patients are in the hospital today, which means that the region is trending a week ahead of the projected peak in local infections.
Long-term projections previously showed West River peak infections would hit in early July. With the actual numbers, the estimated peak time may hit earlier, in late June. And in that time, COVID-19 hospitalizations in Rapid City could grow from 30 today to nearly 400 in late June, based on the South Dakota Department of Health model.
These projections were developed under the assumption that the community’s adherence to social distancing would be at a rate of 50 percent. However, it’s estimated that the community’s adherence to social distancing is likely lower – closer to 25 percent.
Antibody testing results, which indicate whether a person has had the COVID-19 virus in the past, show that the virus has not been present in significant numbers until recently. Of the 2,221 antibody tests completed by Monument Health since April 20, just 21 tests — less than 1 percent — have been positive.
Monument Health is prepared for this potential surge, but it will certainly stretch capacity from both a space and staffing standpoint.
