Heading into the New Year, flu, COVID-19 and RSV activity are at high levels in McHenry County.

According to the McHenry County Department of Health’s respiratory illness surveillance report, which covers the week of Dec. 21-27 and is the latest available, respiratory illness as a whole and flu, COVID and RSV are all at peak levels.

Flu has been at high levels in the county for the past several weeks, including the lead up to into the holiday season.

In McHenry County, emergency department visits for flu were up “61.6% last week in comparison to the previous week, with most visits among those aged 0-24 years.” Inpatient admissions for flu were up 89.5% in the same time frame, according to the report.

The rapid influenza diagnostic test positivity percentage from “sentinel hospitals” in the report was 34.27% for influenza A and 9.94% for influenza B.

“The flu test positivity rate in the report includes results from hospitals that regularly share data with the McHenry County Department of Health. In most cases, this reflects tests performed at hospital locations. One hospital system also includes flu tests from its outpatient sites within McHenry County. While testing locations can vary, the week-to-week changes in the positivity rate help us understand overall flu trends in the community,” health department spokesperson Nick Kubiak said.

Nationally, flu has been on the rise, which has been driven by a new variant, “subclade K,” the Associated Press reported. The Centers for Disease Control and Prevention estimates high or very high levels of illness activity in more than half the states.

The CDC estimates “at least 7.5 million illnesses, 81,000 hospitalizations and 3,100 deaths from flu so far this season. That includes at least eight child deaths — and is based on data as of Dec. 20, before major holiday gatherings," the AP reported.

The new variant has caused early outbreaks in the United Kingdom, Japan and Canada, the AP reported.

“The flu virus is a shape-shifter, constantly mutating, and it comes in multiple forms. There are two subtypes of Type A flu, and subclade K is a mutated version of one of them, named H3N2. That H3N2 strain is always harsh, especially for older adults,” the AP reported.

This year’s flu vaccine doesn’t perfectly match the new variant, but "a preliminary analysis from the Unted Kingdom.found it offered at least partial protection, lowering people’s risk of hospitalization," according to the AP.

In Illinois, respiratory illness activity is “high” with flu activity “very high”, COVID-19 “moderate” and RSV “low” as of Jan. 2, according to the state’s dashboard.

In McHenry County, emergency department visits for COVID-19 were up “233.3% last week in comparison to the previous week, with most visits among those aged 65 years and older,” according to the health department report. Inpatient admissions were up 275%.

For RSV, emergency department visits were up 42.9%, with most visits among those age 4 or younger. Inpatient admissions for RSV were down 50%, but there was one RSV-related ICU admission, according to the report.

The full report is available on the health department website.