NY Update. I am a bit more convinced today that the surge in cases we are seeing in Westchester is not entirely — maybe even not primarily — caused by the micro cluster in Port Chester.

There were 242 new cases in Westchester yesterday, on 5538 tests, yielding a testing-positivity number of 4.38%, which is an increase over yesterday. Even on a rolling seven-day average, we are now over 3%.

As I mentioned in my post yesterday, Gov. Cuomo said Westchester is relatively flat without the Port Chester hot spot. That seems overly optimistic to me. I think there is wider spread generally in the county.

I’ve looked back at the maps that Westchester County publishes showing COVID cases in each municipality, and back on October 21, Port Chester had around 50 active cases, and by comparison Pelham had 10 active cases. (Port Chester has a population about three times that of Pelham, but has more multi-family dwellings, so that may account for the difference to some extent.)

Over the next week or so, Port Chester’s number of active cases grew by a handful each day, such that by October 29, it stood at 79 active cases. But in the first week of November, it reported 83 new cases. Frustratingly, the county only publishes its maps on week days, and didn’t publish one on Election Day, so there are some gaps in terms of how many cases have shown up each day. But that’s a pretty clear spike.

Yesterday, the county reported 20 new cases in Port Chester, which I assume covers results over the weekend. Today, the map shows 17 new cases in Port Chester, with 140 active cases:

While Port Chester’s outbreak is meaningful, there were still 225 new cases in Westchester yesterday, excluding Port Chester. As we’re now averaging 217 cases per day countywide over the past week, 17 new cases in Westchester are just not enough to skew the numbers drastically. If you remove the Port Chester cases from the totals yesterday, the Westchester testing positive number would still be around 4%.

Note that we have reached 26 active cases in the Pelhams. I’ve looked back at the old maps for Westchester, and it looks like the county only started tracking active cases in early May — before that they just showed total cases to date. But as of May 6, for instance, the county was reporting a total of 15 active cases in Pelham and Pelham Manor. While we clearly had more active cases in the Pelhams prior to that (during March and April), we do seem to be moving into a more active period now than we’ve been in since April.

One of the issues with this virus, as we learned in the spring, is that whatever new case numbers we’re seeing, the likely actual number of infections is some multiple of that number. At nearly 1500 cases per week now that we know about, there could be many thousands of non-symptomatic infections in the county. To some extent, it appears this groundswell of hidden cases may contribute to the rapid acceleration of infections. There are just more chances — even if still low at present — of encountering someone who is shedding virus.

My hope is that the multiple of actual to identified cases is not as high right now, and that the wearing of masks and social distancing will continue to limit the rapid spread. But given that we’ve quadrupled the number of daily cases over the past month in Westchester, and doubled the number of people hospitalized during the same time frame, we need to be vigilant.