BA.5 spreading COVID in Michigan. Five things you should know.

The subvariant BA.5 appears to be fueling a resurgence of COVID cases in Michigan as it ducks vaccines and natural immunity and reinfects some people sick with COVID just weeks earlier.

“We see people who get COVID, then a month later, they have COVID,” said Dr. Catherine Bodnar, medical director at Midland County’s Department of Public Health. “They fully recover, and then, they have symptoms and they test and they're positive again.” 

“There was that old rule that you were good for 90 days,” Bodnar said, referring to the understanding that natural immunity from a COVID infection lasted about three months.

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“That's out the window,” she said.

For some, BA.5 appears to evade vaccine protection.

At Beaumont Health  — among the state’s biggest health systems —  nearly 1-in-3 patients hospitalized Tuesday with COVID had not only been vaccinated, but had at least one booster.

Still, vaccines remain the best defense against getting severely sick or dying from COVID, Bodnar and other health experts told Bridge Michigan Tuesday. 

“The big takeaway is to make sure you're up to date on your vaccine,” she said.

For people 50 and older or those 12 and older who are moderately or severely immunocompromised, that means at least four vaccines now for those who had the initial two-dose regimen.

On Tuesday, White House officials said the CDC and Food and Drug Administration are considering expanding eligibility for the second booster.

What is BA.5?

BA.5 is the latest iteration of the COVID omicron variant first detected in November. Omicron quickly drove the winter surge, replacing delta as the dominant variant and driving COVID hospitalizations to the highest levels ever in Michigan — 5,009 patients with suspected or confirmed COVID on Jan. 10.

Until recently in Michigan, cases, hospitalizations and deaths had all fallen.

But since November, omicron has undergone at least a half-dozen changes and continues to drive the pandemic, accounting for nearly all global COVID infections. All but 0.1 percent of the 34,846 COVID samples sequenced, then reported last month to a global nonprofit that collects and shares genetic information on coronaviruses, were omicron.

About 2-in-3 COVID cases in the Midwest now are believed to be BA.2, according to the CDC.

On Tuesday, Michigan case counts jumped 30.4 percent in a week, to nearly 2,000 cases per day. Case rates are rising in Detroit and in 45 of the state’s 83 counties, although they remain far below the rates seen during the initial omicron wave in January, according to state data.

Overall case numbers are likely far higher than the official number, Bodnar and other experts say, because of the prevalence of home tests — which are far less likely to be reported to health authorities, even when people test positive — and because, for most people, the symptoms have been relatively minor. 

That has some falsely reassured, Bodnar said.

“People want it to be over. They've decided it's over. And it's not,” said Bodnar, who also is president of the Michigan Association of Public Health and Preventive Medicine Physicians.

How much more transmissible is BA.5?

BA.5 appears to be more transmissible than previous subvariants, but by how much is unclear, said Laura Bauman, manager of Washtenaw County Health Department’s epidemiology program.

“Last June, those of us working on the COVID response team were rooting for what we called the ‘triple zero day,’ where we'd have zero new cases, no hospitalizations and no deaths,” she said. This June, we didn’t get close,” said Washtenaw’s Bauman.

In fact, 80 people were hospitalized with COVID in Washtenaw County in June, she said.

In addition to the climb in cases, the number of deaths and hospitalizations also rose Tuesday. The state reported 122 deaths for the week, up from 57 the prior week but lower than the 146 the week before that. Statewide Tuesday, 912 patients were hospitalized with suspected or confirmed COVID, up from 830 patients on Friday and 762 on July 1.

There are complications in the data, Bauman said. In addition to positive cases that go unreported, other circumstances have also changed in Michigan, some for the better. More than 5.7 million Michiganders are now fully vaccinated, according to the state, making it more likely that some people now hospitalized with COVID are likely there for other reasons and just happened to be diagnosed during routine testing, said Dr. Matthew Sims, head of infectious diseases research at Beaumont.  

A hospital’s data doesn’t make clear “if they're there because of COVID or they just happen to have COVID” that may be mild, he said. 

There’s another reason it’s difficult to track transmissibility right now: Some who were vaccinated against COVID may be infected with the latest subvariant without realizing it because they are only mildly ill or not ill at all, he said.

In April, the U.S. Centers for Disease Control and Prevention estimated that nearly 60 percent of Americans had been infected with COVID at some time during the pandemic. In Michigan, the state reported nearly 2.3 million cases, as of Tuesday, but it’s not clear how many of those are reinfections.

Does it cause more serious illness?

Not clear.

Hospitalizations are climbing, yes, but that may be a reflection of a higher case count, Bodnar said.

“If it's more transmissible and there's more cases, then we're going to see more hospitalizations,” she said. “But that doesn't necessarily mean it's more severe than other variants.”

Do vaccines work against it?

The effectiveness fades over time, and many Michiganders haven’t had a COVID jab since they first lined up for one more than a year ago, said Washtenaw’s Bauman.

Even those who lined up for the first boosters are now six months away from that latest shot, she noted.

In June, nearly half of those hospitalized with COVID in Washtenaw County were not only vaccinated, but had received a booster, she said.

Bauman said many of those who are hospitalized with COVID in Washtenaw County are older or have underlying chronic conditions.

“It’s why it’s so important to keep up-to-date on the vaccines,” she said.

Are we poised for another wave?

Also hard to say.

The biggest thing going for Michigan now is its weather and our pull to be outdoors where transmission is less likely, said Bodnar.

She said her bigger concern is in the fall, when people return to the indoors, possibly to be greeted by yet another variant.

“I do think we have our weather in our favor in Michigan for the summer, so I'm keeping my fingers crossed,” she said. “But I do admit I am worried.”