Case Prevalence Per 10,000, By Town
For the week ending March 24, 2021

Connecticut has broken out of the stasis of the past six weeks, and not in a good way. Both raw case numbers and case prevalence, or the number of cases per 10,000 people, rose significantly. New, more contagious COVID-19 variants are the likely culprits.
Ever since the end of February, the number of cases had held fairly steady in the 5,000-6,000 per week range. That changed this week as cases jumped to 7,694, an increase of 36% over last week. Case prevalence rose from 15.87 new cases per 10,000 people to 21.53, and test positivity also increased from 2.9% to 3.5%.
State officials now believe that the more contagious variant first found in Britain, which was responsible for a dramatic rise in cases in the United Kingdom a few months ago, comprises anywhere from 30% to 40% of new infections.
Ever since it became clear that the variants would be spreading here, the state has been in a race to vaccinate as many people as possible before the variants became a majority of cases. We seem to be coming to that point right now. About 36% of residents have had at least one dose of a vaccine, while about half of that group have been fully vaccinated.
What does this mean for a possible third wave? Hopefully, because the state has prioritized vaccinating the more at-risk age groups, both hospitalizations and deaths will not spike sharply even if case numbers do. Hopefully, as more and more of us are vaccinated, another wave of infections driven by these variants will be much milder than the ones we saw last April and this past winter.
Let’s take a look at the map.
The most obvious feature here is the sudden sharpening of a pattern that has been building for the past few weeks: a much greater share of cases in the southwestern third of the state. Fairfield, New Haven, and southern Litchfield counties all have much higher prevalence numbers than the rest of Connecticut. It’s impossible to tell right now whether this means that the B.1.1.7 variant has become more dominant there, but it would be one explanation for why this pattern has emerged. New York, and New York City in particular, have been struggling with variants causing more cases; if the variant was spreading here from New York, this is what it would look like.
Towns in this region mostly have a case prevalence of 20-30 new cases per 10,000 people, while communities in the rest of the state generally are in the 10-20 range. Six towns — Waterbury, Ansonia, Derby, New Milford, New Fairfield, and Union — all had a case prevalence of over 40. All but Union are in the southwestern third of the state.
Six towns — Sharon, Barkhamsted, Ashford, Eastford, Scotland, and Franklin — reported no new cases this week.
We should be prepared for these new variants to spread quickly across the rest of the state. Practical precautions like mask wearing and social distancing are still very effective ways to stay safe, even after receiving vaccine shots.
Still, expect there to be calls for the governor to reverse some of his decisions to reopen much of the state’s economy as the situation worsens.
Here is last week’s map for comparison.
Case Prevalence Per 10,000, By Town
For the week ending March 17, 2021
Susan Bigelow is an award-winning columnist and the founder of CTLocalPolitics. She lives in Enfield with her wife and their cats.
The views, opinions, positions, or strategies expressed by the author are theirs alone, and do not necessarily reflect the views, opinions, or positions of CTNewsJunkie.com.