Local COVID-19 updates

As of 4PM today, the Commonwealth of Massachusetts is reporting 10 newly reported confirmed deaths (5 less than yesterday - down 33.3%) for a total of 8,917 deaths, 370 newly reported confirmed cases (46 less than yesterday - down 11.1%) for a total of 120,824 cases, and 17,731 new patients tested by molecular tests (3,058 less than yesterday - down 14.7%) for a total of 1,857,664 individuals tested, with a total of 2,704,512 molecular tests administered to date. The ratio of newly confirmed cases to individuals tested by molecular test is 2.1%, compared to 2.0% yesterday. The state also reported zero newly reported probable deaths (1 less than yesterday) for a total of 208 deaths, and zero newly reported probable cases (22 less than yesterday) for a total of 1,738 cases. The state also reported 306 patients tested by antibody tests (52 less than yesterday - down 14.5%) for a total of 114,941 patients, and 340 patients tested by antigen tests (1,157 less than yesterday - down 77.3%) for a total of 92,907 patients. Combining the confirmed and probable numbers gives 10 new deaths for a total of 9,125 and 370 new cases for a total of 122,562.

The seven day average number of newly confirmed cases per day is 334.4 compared to 376.1 last week (down 11.1%) and 242.0 two weeks ago (up 38.2%). The seven day average number of newly confirmed deaths per day is 14.4 compared to 18.0 last week (down 19.8%) and 13.8 two weeks ago (up 4.3%). The seven day average number of molecular tests per day is 20,519.4 compared to 24,266.4 last week (down 15.4%) and 17,166.2 two weeks ago (up 19.5%). The seven day average percentage of tests coming back positive per day is 1.7% compared to 1.5% last week and 1.4% two weeks ago. (The above averages are calculated from today's raw data download.)

Of the Commonwealth's four "key metrics" listed on page 2 of the report, the seven-day weighted average positive test rate is 0.9%, 0% above the lowest observed value of 0.9% on September 5. The three-day average number of COVID-19 patients in hospital is 323, 7% above the lowest observed value of 302 on August 29. The number of hospitals using surge capacity is 0, 0 above the lowest observed value of 0 on September 5. The three-day average number of COVID-19 deaths is 14, 34% above the lowest observed value of 11 on August 4.

Given it's not just the weekend but a long weekend, I'm not at all surprised that the day-to-day deaths, cases and test counts are all down; less reporting is only to be expected. Not expected, and not pleasing, is the continued uptick in the ratio of newly reported cases to newly reported tests. The seven-day averages show mostly mixed results; deaths, tests and cases are all down from the previous week, but up from two weeks ago. That percent-positive ratio, on the other hand, keeps creeping up.

Oddly, though, the "key metric" percent-positive is hitting new lows every day. I think that's because that ratio is defined in the "Data dictionary for Key Metrics Excel sheet.docx" file (in the raw data download) as:

The number of positive tests on that date divided by the number of new tests on that date

In other words, the state is doing two things differently from I. First, they're using the date when the patient was tested, rather than the date that test is reported to the Department of Public Health; given that there's a lag between when the test is performed and when it's reported to DPH, anything that took more than a week to process ends up rolling off the state's seven-day average. Secondly, they're counting all tests on a given day, even if there are multiple tests for a particular individual; that could certainly be boosting the denominator of the ratio.

The town of Acton has yet to post an update today. As of the most recent report at 3PM on August 31, the town of Acton reported 198 cumulative cases of COVID-19 in town with 4 individuals in isolation, 173 recovered and 21 fatalities.