Our local (COVID) weather

Navigating life at this point in 2021 is like checking the weather forecast: What you feel safe doing should depend on where you are, how vulnerable you and the people you live with are, and what's happening or predicted to happen in your area. The same applies to anyplace you might plan to travel to.

This concept is the basis for the new CDC recommendation that fully vaccinated people should always wear masks in public indoor spaces in counties where COVID activity is substantial or high. (See county-level activity here; orange is substantial and red is high.)

That guidance is based on new knowledge about vaccinated people's ability to catch and spread the Delta variant, even as the vaccine protects people from severe disease if they do catch it.

In moderate or low transmission areas, a vaccinated person could choose to wear a mask too, of course. That's especially true if they, or someone they live with, is more vulnerable to the virus because of age (kids under 12 can't be vaccinated yet) or medical conditions or treatments that might reduce the vaccine's ability to protect them, such as a transplant, cancer or autoimmune disease.

But vaccinated people fortunate enough to live in areas of moderate transmission (most of Michigan and the Northeast, as of today) might be feeling pretty good right now.

However, even our forecast has some clouds.

How many clouds depends on exactly where you live. In this post I'm sharing the latest snapshots of COVID case rates for Plymouth-Canton-Northville, and for all communities in Wayne County, from the site built by U-M epidemiologist and Plymouth resident Emily Somers, Ph.D. and her students. You can explore case rates over time for individual communities, and combinations of communities, on her site here.

Our little corner of Wayne County is doing fine, but maybe ticking upward toward the Substantial level of transmission (the orange horizontal line at 50 cases per 100,000 people in the past 7 days).

Many communities in Wayne County are already in the Substantial category and a few (Melvindale, Grosse Pointe Shores and Flat Rock) just crossed into High (above the red line) transmission, which is where most of the country is right now.

So it remains to be seen how long Wayne County remains yellow on CDC's map -- or whether we will join much of the rest of the country in being a place where all vaccinated people should wear masks in indoor public spaces.

The third image in this post hints at why there's so much variation in rates within our county.

It shows vaccination rates among people over 18 as of late May in western Wayne County. Each community is broken up into several Census tracts, which are different from ZIP codes.

In this case red is good - it means a higher percentage of adults were vaccinated. Here's where you can see the whole Michigan map of vaccination data by Census tract. You can drill down to individual areas. (And while you're doing it, please consider donating to Bridge Michigan, the nonprofit news organization that obtained this detailed data from the state health department and made this map.)

On a national level, we know that the higher the vaccination rate in an area, the lower the case rate in that place. The CDC has an interactive color-coded map that lets you see how counties are doing on that.

So - just like you keep an eye on the weather forecast before going out, and you don't plan a vacation to a place when you know it's about to get hit by a hurricane or blizzard that could ruin your trip, this is a good time to get used to checking the "COVID weather" for your area or destination.

If the map shows yellow or blue, and you're vaccinated and not immunocompromised or living with someone who is, the odds are in your favor. Just like you might decide to leave the umbrella at home when the chance of rain is 20%, but bring it if the chance is over 50%, you could decide to do the same with your mask (unless the place you're going to requires it, like an airport or a doctor's office).

It could still rain even if the forecast says the chance is only 20%. And you can still get mildly sick even if you're vaccinated and healthy, or spread the Delta variant even if you don't know you've caught it and your immune system fought it off.

Weather forecasts change. COVID "weather" will change too. It's up to us to keep an eye on the map and act accordingly.