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Michigan had 13 confirmed omicron cases in 6 counties, but actual prevalence could be much higher -

A month ago, no one had heard anything about the omicron variant, discovered in South Africa and reported to the World Health Organization on Nov. 24.

In just 30 days, the variant has been identified in all states and six Michigan counties, including Wayne, Washtenaw, Oakland, Macomb, Genesee and Kent. There had been 13 confirmed Michigan cases, as of Wednesday, according to the Michigan Department of Health and Human Services. Macomb County had the most with four.

Believed to be extremely contagious and adept at evading immunity, it is almost certainly more prevalent than now known, doctors said.

Routine testing does not reveal variants and only a small number of samples undergo genomic sequencing in labs to determine strains. This takes time, lagging real-world spread.

“It’s likely that the true burden of omicron is probably much higher than this,” Dr. Christopher Ledtke, infectious disease expert with Munson Healthcare based in Traverse City, said this week during a call with reporters.

Based on new, reported cases per 100,000 people in the two days ending Wednesday, three of the top 10 counties had confirmed omicron cases – Macomb, Oakland and Wayne counties. These counties also ranked among the worst considering new cases without adjusting for population, indicating high levels of transmission.

Henry Ford Health System, based in Detroit, is already working as if omicron is the dominate strand, discontinuing use of one monoclonal antibody treatment considered ineffective against the variant. The total number of tests and the percent positivity, at more than 25%, increased earlier this week in the Henry Ford system, consistent with omicron taking command, said Dr. Bruce Muma, CEO of the Henry Ford Physician Network and director of Henry Ford’s monoclonal antibodies program, the largest in the state.

Time this with inevitable travel and holiday gatherings among people weary of COVID precautions, and healthcare leaders are bracing for another influx in infections and hospitalizations.

Even if the resulting disease is milder than with previous variants, as early data indicates, the high volume could exacerbate a continuing hospital crisis in a state where the number of new, reported cases of COVID-19 have been high for months.

More contagious

The omicron variant has more than 50 significant mutations, and with these, it behaves differently than previous strains. “It’s almost like a new pandemic develops within a pandemic,” Ledtke said.

Compared to the delta variant, which drove the fourth surge in Michigan, leading to record hospitalization, omicron is four times more contagious. “It’s one of the most contagious viruses known to man,” Ledtke said.

In South Africa, it took less than two weeks for omicron to become dominate. It took delta more than six weeks, he said.

It has a doubling time of 1.5 to 3 days, meaning in as few as 1.5 days, the number of new cases in a population doubles. “Which is extremely fast,” Ledtke said.

He noted a Christmas party in November in Norway, where about 70% of more than 100 participants tested positive for SARS-CoV-2. Seventeen were shown to have been infected with the omicron variant, according to the Norwegian Institute of Public Health. Though there were not sequencing results available, it is assumed the others were infected with the same variant

Additionally, more than 60 people who visited the restaurant the same evening tested positive.

Cough, lethargy, headache and sore throat

All put one in the Norway outbreak diagnosed with COVID-19 reported symptoms, usually cough, lethargy, headache and sore throat. There were no reported hospital admissions.

Most reported symptoms within three days, the institute reported, which might indicate a shorter incubation period. With delta, it was closer to four to five days, and with the ancestral strand, symptoms appeared within about six days, Ledtke said.

Based on a report from the University of Hong Kong, the variant is adept at infecting respiratory mucosa, meaning airways and nasal passages. Because a significant amount of virus is shed from these sites, this likely contributes to its high transmissibility, Ledtke said. The researchers determined omicron “infects and multiplies 70 times faster than the delta variant and original SARS-CoV-2 in human bronchus.”

Less severe disease?

Omicron, however, did not appear to invade lung tissue nearly as well, which is consistent with reports the resulting disease is less severe, the Hong Kong research showed. (Ledtke noted, however, this was an in vitro study, meaning done in a controlled environment, such as a test tub or petri dish.)

In early December in South Africa, of 42 mostly unvaccinated patients hospitalized, 29 were breathing ordinary air and only one was in intensive care, according to the New York Times, citing the director of the Office of H.I.V./Aids and Tuberculosis Research at the South African Medical Research Council.

A study released last week by the country’s largest health care administrator, found 29 percent fewer people were being admitted to the hospital than during the first wave of infection in 2020, according to Discovery Health. There was also a lower propensity of admission to high-care and intensive-care units relative to prior surges, the insurer reported Dec. 14.

“Issue some caution that even with a lower incidence of hospitalization and death, it still has the capability to significantly overwhelm the healthcare system based on the transmissibility alone,” Ledtke said.

Doctors are especially concerned about first responders and essential workers at high risk of omicron infection, which might result in lost work days, further stressing an already stretched, understaffed and overwhelmed healthcare system.

In the seven days leading up to Tuesday, Dec. 21, Henry Ford, which mandates vaccines and employs about 33,000, had 113 team members call-in to work because they tested positive for COVID-19. On Tuesday alone, almost 100 employees did not go to work because they contracted COVID-19, said Bob Riney, chief operating officer and president, healthcare operations. “We are already dealing with a very depleted workforce, an exhausted workforce.”

Immune escape

All data points to a drop in vaccine efficacy with the omicron variant.

Discovery Health, in its analysis released last week, found two doses of the Pfizer vaccine provided only 33% protection against COVID-19 infection and reduced the chance of hospitalization by 70% during the current omicron wave. In comparison there was about 80% protection from infection and 93% protection from hospitalization with delta.

The insurer looked at more than 211,000 COVID-19 test results. About 40% of them had received two Pfizer shots.

Further, it found chance of reinfection was significantly higher compared to prior variants. People infected with delta in South Africa face a 40% relative risk of reinfection with Omicron. With its predecessor, beta, they face a 60% risk of reinfection, according to Discovery Health.

Those who are vaccinated are better off with three shots of the Pfizer and Moderna vaccines, now considered better options than the Johnson Johnson vaccine, data indicate.

Almost immediately after news of omicron made headlines around the world, the U.S. Center for Disease Control and Prevention changed recommendations on boosters, saying all adults should receive them.

In a small sample, Pfizer found two doses to be significantly less effective against omicron, but a booster shot increased by 25-fold people’s levels of virus-fighting antibodies.

Just this week, Moderna reported a third dose, authorized and administered in a smaller quantity than the primary doses, can boost neutralizing antibody levels 37-fold higher than pre-boost levels. Double the dosage, and the increase is 83-fold.

Dr. Nick Gilpin, Beaumont Health’s medical director of epidemiology and infection prevention, sees the news on boosters as positive. “It’s certainly not a guarantee that you may not get sick, but it’s a much lower chance of getting severe disease, severe illness, hospitalization and of course, death. Those are the things that we definitely want to prevent,” he told reporters this week from Beaumont Hospital in Royal Oak.

Much remains unknown

There is still a lot to learn about the variant, and much remains unknown.

One compelling question: How do delta and omicron interact? Does omicron confer good protection against delta and vice versa? “We don’t quite know that yet,” Ledtke said.

The data is preliminary.

One thing Americans should expect is significant transmission. The next 2-4 weeks will be “very challenging” for the United States, he said.

Possible game-changer

Some doctors said high transmissibility and less severe illness might be positive for the long pandemic.

“The bright side to the omicron variant is that it may be the game changer for which we had been hoping. That is, if a lot more people get sick with a milder illness, we may then achieve the herd immunity needed to end the pandemic, without all the devastation,” said Dr. Jon Sangeorzan, infectious disease expert at McLaren Northern Michigan in Petoskey.

Read more on MLive:

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