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Does Michigan report the number of breakthrough COVID cases?

Local 4′s Dr. Frank McGeorge answers questions about COVID, the vaccine

DETROIT – Since the coronavirus pandemic began, Dr. Frank McGeorge has been keeping viewers up-to-date and informed on all fronts. He’s been answering your questions about the vaccine, the vaccination process and more.

Read: More answers to questions about coronavirus


When they report the number of COVID cases do they include those that are breakthrough cases or are they just people that haven’t been vaccinated?

The number of COVID cases being reported, now three times a week, include unvaccinated and breakthrough cases.

Between Jan. 15 and Sept. 21 there were just over 500,000 COVID cases identified in Michigan and about 6.2% of them, 30,000 were in fully vaccinated people.

You reported that since January vaccinated individuals make up only 8% of hospitalizations. What about since delta? I’ve heard that number is significantly higher now in Michigan. What are the latest percentages?

Delta has made a difference. Data from the state shows that in the 30 days between Aug. 23 and Sept. 21, 18% of cases, 21% of hospitalizations and 15% of deaths were among fully vaccinated individuals.

Beyond any effect from delta, those numbers require two other pieces of information to put them in context. First, the percentage of fully vaccinated Michigan residents was approximately 57%. If the vaccine no longer had an effect we would have seen roughly the same 57% of cases, hospitalizations and deaths among the fully vaccinated.

The lower percentages among the fully vaccinated demonstrates the vaccine is still having a significant beneficial effect. The other element to be aware of has to do with understanding the math behind these statistics and why there would appear to be more breakthrough cases now compared to a time when there were fewer people vaccinated.

When nobody was vaccinated, nobody could be considered a breakthrough. If 100% of people were vaccinated then any infection would be a breakthrough. Essentially, as we vaccinated more people, a larger proportion of cases will be breakthroughs.

Because we vaccinated the oldest and highest risk people first, it’s also likely that their immunity is decreasing as the months go by -- putting them at higher risk from the delta variant. That’s where booster shots will play a critical role in protecting the most vulnerable moving forward.

Read: Complete Michigan COVID coverage


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About the Authors
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.

Kayla Clarke headshot

Kayla is a Web Producer for ClickOnDetroit. Before she joined the team in 2018 she worked at WILX in Lansing as a digital producer.

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