As Delta spreads in Michigan, some counties are more vulnerable than others

State health experts have now identified 54 cases of the Delta variant of the coronavirus in Michigan.

While is may seem a small number, there are likely many more cases. Identifying a variant requires scientists to capture a sample from an infected person and sequence the virus’s genetic code. That’s expensive and time-consuming, and doesn’t happen very often.

But we can still predict where Delta is likely to pop its head up.

The Delta variant is estimated to be 60% more transmissible than the Alpha variant (B.1.1.7) that is currently dominant in the U.S. That Alpha variant is 50% more transmissible than the original versions of the coronavirus.

However, health experts say COVID-19 vaccines are mostly effective against the Delta variant. That means that areas with a higher percentage of vaccinated people are less likely to find cases.

Conversely, less vaccinated areas are more likely to get a visit from Delta or other variants.

Case in point, Kalamazoo County boasts a vaccination rate of 58%. That’s higher than the statewide rate of 53%.

We aren’t sure how many cases of the Delta variant exist in Kalamazoo County because the state doesn’t break out those numbers. But we do know there are 276 confirmed cases of Variants of Concern (VoC), which includes Delta and Alpha.

That calculates out to about 1.2 cases of variants per 1,000 people in Kalamazoo County.

Nearby Branch County has a fully-vaccinated rate of 40%. With 84 cases of a VoC, Branch County’s rate is almost double Kalamazoo’s – 2.3 cases per 1,000 people.

So far, the Delta variant isn’t dominating – in Kalamazoo or Branch County. Only time will tell if and where it leads to outbreaks.

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