Illinois is seeing a ‘quademic’ of viruses, and this year’s peak may last longer

Illinois is seeing more transmission of respiratory infections and norovirus this season, even compared to a typical winter, and medical professionals recommend residents take precautions.

Between COVID, respiratory syncytial virus (RSV), influenza and norovirus, some health care professionals say we are experiencing a “quademic,” Dr. Vidya Sundareshan, infectious diseases specialist at Southern Illinois University Medicine and medical advisor to Sangamon County Health Department, said in a Jan. 9 interview with the News-Democrat.

The Illinois Department of Public Health reported Jan. 7 the state is at a “high” level for respiratory illness activity, and emergency department visit rates have recently more than doubled for flu and increased for COVID, as well.

The state health department also issued a health alert to hospitals and health care facilities recommending they take note of local conditions and “consider targeted steps to mitigate the circulation of seasonal illnesses,” which could include visitor restrictions and masking requirements, the press release said.

“The New Year has arrived, and Illinois is experiencing the expected winter surge in seasonal respiratory illnesses,” IDPH Director Dr. Sameer Vohra said in the release. “It is now more important than ever to use the many tools at our disposal to keep ourselves and our loved ones safe. The most effective tool remains vaccinations for flu, COVID-19, and RSV. It is not too late to get your vaccines, as the seasonal respiratory season can extend late into the spring.”

Norovirus in Illinois

While a seasonal uptick in respiratory viruses is expected in winter each year, we’re still seeing higher overall numbers than in previous seasons, Sundareshan said. Along with respiratory viruses, a “very contagious” stomach bug is also causing illnesses.

Norovirus numbers are up nationally this year compared to what we typically see, Sundareshan said, and the illness often causes nausea, vomiting, abdominal pain and diarrhea.

“Thankfully, it’s very short-lived,” Sundareshan said.

Someone who is exposed to norovirus may start experiencing symptoms within 12 hours, and they usually resolve within 48 hours. No antivirals are available for norovirus, Sundareshan said, but it’s important for people with the illness to stay hydrated and avoid sharing food with others.

While there is a PCR test that can detect norovirus, Sundareshan said it’s not used very frequently because by the time test results come back, a patient’s symptoms have typically resolved. Clinical suspicions are generally pretty accurate in diagnosing norovirus, she added.

Illinois peak respiratory virus season might last longer

As for respiratory viruses, influenza A transmission has been particularly high this year, even though December and January usually bring an increase in flu B. When the season peaks, we still usually see flu activity for a month or two afterwards, Sundareshan continued. Flu season is generally considered to span from late September to May.

“It is anticipated that the peaks might last a little bit longer,” Sundareshan said about this year’s flu season.

Some epidemiologists expect we will experience longer peaks or longer post-peak transmission periods for all respiratory viruses this year, Sundareshan added.

To date, this respiratory season has led to the deaths of six Illinois children, IDPH reports, including one pediatric fatality from COVID-19, four from influenza and one from RSV.

Transmission has increased for RSV, Sundareshan said, and young children and adults older than 75 years are at the greatest risk of severe complications.

“Right after the holiday season, we have a lot of people gathering, traveling, and then COVID numbers are relatively higher, as well,” Sundareshan said.

The metro-east has seen five reported COVID outbreaks in congregate settings recently, according to IDPH. Across the U.S., more than 103 million cases and 1.2 million deaths from COVID have been reported since the beginning of the pandemic, according to KFF, a nonprofit organization that reports public health information.

Another contributing factor to this year’s respiratory season are adenoviruses, which are common and usually cause mild cold- or flu-like symptoms, the U.S. Centers for Disease Control and Prevention reports. An adenovirus infection can also cause fever, sore throat, acute bronchitis, pneumonia, pink eye and acute gastroenteritis.

Here are the latest available statewide test positivity numbers, from IDPH:

• Adenovirus: 0.8%
• COVID: 6.6%
• Flu: 11.7%
• RSV: 12.5%

How to mitigate virus transmission

Some of the most important factors to reducing transmission of respiratory viruses are to improve air circulation, such as by opening a window when it’s not too cold out, hand washing and avoiding others when you are sick, Sundareshan said.

Another important tool is vaccination. Vaccines are available for COVID, influenza and RSV, though the recommendations for the RSV vaccine are narrower.

People who are 6 months of age or older are eligible to receive a COVID vaccine, but Sundareshan said in her experience as a practitioner, many people are not willing to get an updated shot.

“Those conversations have been relatively a little harder, because people feel like they’ve taken so many booster doses for COVID,” Sundareshan said.

While some people may simply be fatigued after repeated vaccinations, others may have concerns that they could contract the flu or COVID from being vaccinated. This is not possible.

“Flu vaccines, COVID vaccines, they don’t have the actual virus. They’re just parts of viruses and it’s an attenuated vaccine or a killed vaccine,” Sundareshan said.

Vaccines work by imitating a natural infection to evoke an immune response so a person’s body can learn how to fight a disease without experiencing the full infection. Flu and COVID vaccines are not 100% effective in preventing someone from contracting the illness, but are effective in protecting against hospitalization and death.

Receiving a COVID vaccine may also help reduce the chances of contracting long COVID.

In St. Clair County, you can schedule an appointment for a flu vaccine or COVID vaccine at CVS, Walgreens and the public health department.

Editor's note: This story was originally published by the Belleville News-Democrat. Meredith Howard is a reporter for the Belleville News-Democrat, a news partner of St. Louis Public Radio.