McHenry County’s COVID-19 positivity rate steadily increasing, reaches 9.2%

McHenry County’s COVID-19 positivity rate has steadily increased for more than a week, reaching just more than 9%.

Region 9, the state-assigned health region that incorporates Lake and McHenry counties, had a total test positivity of 4.4% as of Friday. McHenry County in particular was at 9.2%, while Lake had a 3.3% positivity rate. Lake County conducts about two-thirds of the testing in the region.

There have been differences in McHenry and Lake counties’ positivity rates since the two counties were placed into Region 9, McHenry County Department of Health Public Health Administrator Melissa Adamson said.

“We have worked together to educate the public about the shifts in Region 9 and will continue to do so,” she said.

Test positivity is calculated by taking the number of all positive tests and dividing it by the number of total tests, both positive and negative, then multiplying by 100.

Test positivity is highly dependent on the number of people who get tested, said Susan Karras, the public health nursing director for McHenry County’s health department. The positivity rate also depends on whether a person is tested because they are symptomatic, identified as a close contact or purely for screening and surveillance, Karras said.

An “increasing availability of testing” means it’s no longer accurate to compare current test positivity data to that from earlier in the pandemic, Karras said. Still, multiple metrics that health officials have been using to track COVID-19 trends show an increasing spread of COVID-19 in McHenry County.

“No one metric will give the complete picture of COVID-19 spread within McHenry County, which is why we evaluate other metrics as well and observe trends over time,” Karras said.

Currently, all 11 of Illinois’ health regions are in Phase 4 of the state’s plan for reopening.

Mitigations could be imposed if a region’s test positivity is greater than or equal to 8% for three consecutive days or if a region experiences both a sustained increase in test positivity rates and hospital capacity is threatened.

As of Friday, Region 9 as a whole was on its 83rd-consecutive day below the 8% threshold.

Kim Armour, vice president and chief nurse executive at Northwestern Medicine Huntley Hospital, said they have seen numbers trending upward for hospital admissions.

Warmer weather, the Easter holiday and spring break vacations all factored into this increase, Armour said.

Although health officials are “very happy” about more people getting vaccinated, it also created more movement in the public, she said.

The McHenry County health department has been identifying cases related to spring break as well as outbreaks in schools’ extracurricular activities.

“While the 20-to-29 age group still remains the age group with the highest rates of spread, we are beginning to see increasing rates of spread among the 5-to-19 age group as well,” Karras said. “The increasing rate of cases indicates there is increasing spread of COVID-19 in the younger age groups, which can also contribute to the increasing positivity rate.”

Although the hospital’s general COVID-19 admissions have increased, Armour said they’re seeing less of a demand on its intensive care unit for COVID-19 patients than it did a year ago.

Armour attributed the lower ICU need to a combination of the hospital seeing more of the younger population becoming COVID-19 positive at this time, as the elderly and long-term care facility patients were prioritized for vaccinations.

“They’re out in the communities. They’re traveling, that younger population,” Armour said. “They’re a little more healthy, a little more resilient and again, more mobile for the risk of that cross-transmission to happen.”

Still, the community has to account for those who need health care for non-COVID-19-related reasons such as cardiac arrests, motor vehicle accidents, or strokes, meaning the hospital needs adequate capacity in the ICU for both populations, Armour said.

As more of the population becomes vaccinated, the McHenry County health department expects a decrease in the spread of COVID-19, which Karras said will be reflected in the metrics, including incidence rate and test positivity.

“Until higher levels of vaccination are achieved, mask-wearing, social distancing, staying home when sick, staying home when you are a close contact to a case and avoiding large gatherings is important to decrease the spread,” Karras said.

Armour echoed this, saying COVID-19 guidelines still need to be followed.

“We recognize that our communities are ... ready to be over this pandemic,” Armour said. “But the news of the day is that we need to get to 80% for herd immunity when we talk about our vaccinations.”

Although there is a decreased transmission rate, people shouldn’t start letting their guard down, she said.

“Our hope and intention is that once we get to herd immunity, we’ll start to normalize a little bit more and see less transmission of it by those that are already vaccinated,” Armour said.

From a clinical perspective, Northwestern Medicine is keeping a watchful eye on the positivity rate, Armour said.

“I’m very hopeful that our communities are partnering with us,” she said. “We’re very hopeful that the vaccination programs will continue and we are going to get where we need to be.”