Connecticut is currently dealing with several circulating illnesses at once. COVID-19 wastewater levels in the state are rated “High” by the CDC, influenza activity is increasing statewide, and a more contagious strain of norovirus has been driving a surge in stomach illness. Depending on the time of year, tick-borne diseases also remain a major concern. Here’s a breakdown of what’s spreading and what symptoms to watch for.
COVID-19 Levels Are Elevated
COVID-19 remains one of the most actively circulating viruses in Connecticut. The CDC’s National Wastewater Surveillance System, which detects viral particles in sewage before many people even show symptoms or get tested, currently rates Connecticut’s viral activity level as “High.” That’s the second-highest category on a five-tier scale ranging from Very Low to Very High.
Wastewater monitoring picks up infections that clinical testing misses, including people who are sick but never take a test and those who are infected without symptoms. A “High” reading means there’s significant community spread happening right now, and your chances of encountering the virus in everyday settings are elevated. Common symptoms still include sore throat, congestion, cough, fatigue, and body aches. Some people also report headaches and gastrointestinal symptoms. Updated vaccines are available for free to everyone six months and older.
Flu Activity Is Rising
The Connecticut Department of Public Health reports that statewide influenza activity is increasing. Flu season typically peaks between December and February, but activity can stretch well into spring. Symptoms overlap heavily with COVID (fever, cough, body aches, fatigue), so it can be difficult to tell them apart without a test. Many urgent care clinics and pharmacies offer combination tests that check for both viruses at once.
If you’re hit with sudden-onset fever, chills, and muscle aches that feel like they came out of nowhere, flu is a strong possibility. It tends to come on faster and harder than a typical cold. Antiviral treatment works best when started within the first 48 hours of symptoms, so getting tested early matters if you’re in a high-risk group.
A More Contagious Norovirus Strain
Norovirus cases are rising across Connecticut and the rest of the country. The current surge is being driven by a newer strain called GII.17, which has become the dominant variant circulating in the U.S. While norovirus typically spikes in early winter, this particular strain is drawing extra attention because of how efficiently it spreads.
Norovirus causes intense vomiting, diarrhea, nausea, and stomach cramps, usually hitting within 12 to 48 hours of exposure. Most people recover in one to three days, but dehydration can become serious, especially in young children and older adults. The virus spreads through contaminated food, surfaces, and close contact with infected people. It’s notoriously hard to kill with regular hand sanitizer, so thorough handwashing with soap and water is the most effective way to protect yourself. Wastewater surveillance data has shown sharp increases in norovirus levels across parts of the state.
RSV and Respiratory Illness in Children
Respiratory syncytial virus, commonly called RSV, is another illness that circulates heavily in Connecticut during the colder months. In adults, RSV typically looks like a mild cold. In very young children, it can cause more serious lower respiratory infections, including pneumonia and inflammation of the small airways in the lungs. Children under five are the most affected group nationally, with roughly 58,000 hospitalizations in that age range each year.
Connecticut Children’s Hospital in Hartford has previously seen its pediatric inpatient beds completely full during RSV surges. Signs that a child’s RSV infection may need medical attention include wheezing, rapid or labored breathing, flaring nostrils, and a bluish tint to the lips or fingernails. For most older children and adults, RSV resolves on its own with rest and fluids.
Tick-Borne Diseases Remain a Major Threat
Connecticut is one of the highest-risk states in the country for tick-borne illness, and the numbers from the state’s 2024 tick surveillance program are striking. Of more than 1,000 adult female deer ticks tested statewide, 80.2% carried at least one disease-causing pathogen. More than 17% carried two or more pathogens simultaneously.
Lyme disease is the most common threat. Over 54% of tested deer ticks carried the bacterium that causes it. But Lyme isn’t the only concern. About 15.6% of adult deer ticks carried the parasite responsible for babesiosis, a blood infection that can cause fever, chills, sweats, and fatigue. Another 7.2% carried the pathogen behind anaplasmosis, which produces similar flu-like symptoms. A small number, about 0.3%, tested positive for Powassan virus, a rare but serious infection that can cause brain inflammation.
Nymphal ticks (the tiny, poppy-seed-sized juveniles that are hardest to spot) also carried significant infection rates: nearly 15% with Lyme, over 16% with babesiosis, and about 2% with anaplasmosis. Tick activity ramps up in spring and stays high through fall, with nymphs being most active from May through July. If you spend time outdoors in wooded or grassy areas, checking your body thoroughly afterward is the single most effective prevention step. Ticks generally need to be attached for 24 to 36 hours before transmitting Lyme disease, so prompt removal matters.
How to Tell What You Might Have
With so many illnesses circulating at once, symptoms can blur together. A few patterns can help you narrow things down:
- Mostly upper respiratory (sore throat, congestion, cough, mild fever): likely a cold, COVID, or flu. A rapid test can distinguish COVID from the others.
- Sudden high fever with severe body aches: more consistent with influenza.
- Vomiting and diarrhea with little or no respiratory symptoms: norovirus is the most probable cause.
- Fever, chills, and fatigue after spending time outdoors: consider tick-borne illness, especially if you notice a rash or recall finding a tick on your body.
- Wheezing or breathing difficulty in a young child: RSV or another lower respiratory infection that may need evaluation.
Combination tests for COVID and flu are widely available at pharmacies and urgent care clinics. Norovirus is typically diagnosed based on symptoms alone. Tick-borne diseases require a blood test, and testing is most reliable after symptoms have been present for a few days.