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What you need to understand about Michigan’s COVID breakthrough rate

Health experts say we are in 4th surge

Michigan is nearing its original goal of getting 70% of residents 16 and older vaccinated against COVID -- but case counts are still climbing across the state.

Does that mean the vaccines aren’t living up to their expectation? Dr. Frank McGeorge has a look at Michigan’s current breakthrough rate.

Vaccines aren’t perfect and even vaccinated people do become infected. But that does not mean the vaccines aren’t still having an important effect.

  • Watch the video above for the full report.

View: The latest COVID-19 data

Read: 7 takeaways from expert’s Metro Detroit COVID update: ‘I consider this our 4th surge’

Between Jan. 1, roughly when vaccines became available and Oct. 26 there have been 621,564 new COVID cases. Out of those cases, 552,935 were in unvaccinated people and 68,629 cases occurred in fully vaccinated people. So about 11% of the COVID cases since the start of the year are breakthrough cases. But that 11% is actually an average for the past 10 months.

When you look at the percent of cases that were breakthrough cases since January, you can see at the start of the year they were very uncommon. After June, the percentage of cases occurring in fully vaccinated people -- the breakthroughs have been running in the mid 20% range.

And when you similarly look at breakthrough hospitalizations and deaths, you see exactly the same trend. There has been an increase in the percentage of cases, hospitalizations and deaths since the summer. But the breakthrough data does show the vaccines are working.

For example, in October, when 27% of the new cases were breakthroughs -- 73% of cases were in the unvaccinated. When you do the math and account for the fact that there are more vaccinated people in the state than unvaccinated -- in the time from Jan. 1 to Oct. 26, an unvaccinated person was 13 times more likely to become infected or die from COVID-19.

Another critical piece of information is that people over 65 are far more likely to die from a breakthrough infection -- of the 795 breakthrough deaths since Jan. 1 -- 699, that’s 88% of them were in people 65 years or older.

So does that data say anything about the efficacy of the vaccine?

That’s something the data can’t sort out. Waning efficacy is possible, and there’s also the more contagious delta variant to factor in. That’s why there is the push for boosters and continued mask use when appropriate.

The main reason for the increase in the number of vaccinated people being infected is because a larger portion of the population is now vaccinated.

Read: Complete Michigan COVID coverage


About the Author
Frank McGeorge, MD headshot

Dr. McGeorge can be seen on Local 4 News helping Metro Detroiters with health concerns when he isn't helping save lives in the emergency room at Henry Ford Hospital.

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