Go to the emergency room, or call 911, if flu brings trouble breathing, chest pain or pressure, confusion or sudden dizziness, or severe or persistent vomiting. In children, the warning signs are bluish skin color, difficulty waking, or not drinking enough fluids.
These are the signs named in two provider guides: Lynn Community Health Center’s flu guide, as of November 2026, and Garnet Health’s 2019 article on urgent care versus the ER. Use them to decide quickly, and do not wait to see if things get better.
Warning signs in adults
As of November 2026, Lynn Community Health Center (LCHC) says to go to the emergency room or call 911 for:
- Difficulty breathing or shortness of breath
- Persistent chest pain or pressure
- Confusion or sudden dizziness
- Severe or persistent vomiting
- Symptoms that improve and then return with fever and a worsening cough
Garnet Health’s 2019 article lists chest pain, confusion and respiratory distress or difficulty breathing as severe warning signs of flu. The two lists overlap on breathing, chest pain and confusion.
Warning signs in children
LCHC adds three signs for children: bluish skin color, difficulty waking, and not drinking enough fluids. If your child shows any of these, go to the emergency room or call 911. The breathing and chest signs in the adult list also call for emergency care.
Who is in a high-risk group?
Garnet Health’s 2019 article names infants, the elderly, pregnant women, and people with medical conditions that affect their ability to fight infections as a high-risk group. A 2019 review of seasonal influenza in the Nursing Clinics of North America, indexed by PubMed, says flu symptoms can run from mild to severe. It adds that very young children, people with chronic conditions, people with weakened immune systems, pregnant women and frail older adults can see more illness and death from the virus.
The two providers differ on what to do with high-risk status. Garnet Health sends high-risk patients to the ER. LCHC lists being over 65, under 5, pregnant, or having a chronic condition such as asthma or diabetes as a reason to visit its walk-in clinic. If you are in one of these groups, call your clinician now and ask where you should go if flu starts, so you are not deciding in the middle of an emergency.
Is it the flu or a cold?
LCHC describes a cold as building over 1 to 3 days, with a runny or stuffy nose, sneezing, a mild sore throat, and low or no fever. Colds usually improve within 7 to 10 days. Flu comes on suddenly, often with a fever of 100°F to 104°F, chills, body aches, severe fatigue, a headache and a dry, persistent cough. LCHC says flu symptoms can last 1 to 2 weeks, with fatigue lingering even longer.
The type of illness matters less than the warning signs. If you have any sign from the lists above, go to the emergency room or call 911 no matter which one you think you have.
What about vomiting with flu?
LCHC lists severe or persistent vomiting as an emergency sign for flu. If your main symptoms are vomiting and diarrhea and you do not have flu-type symptoms, ask a clinician or pharmacist where to go. For digestive symptoms more generally, see digestive and general health.
What is happening this flu season?
Flu can range from mild to severe. Cleveland Clinic’s page on severe influenza lists sepsis, stroke and pneumonia among its life-threatening complications.
How can you lower your chance of needing the ER?
Medicare says flu vaccines can keep you from getting sick with seasonal flu during the fall and winter. It also says people 65 and older can get a trivalent flu vaccine to lower the risk of hospital visits and death. Medicare’s flu vaccine page lists where to get one, including your doctor’s office and local pharmacies. For more on how the immune system fits into everyday health, see gut health and immunity.
Before you go
- Call 911 for any warning sign listed above, adult or child.
- If you are in a high-risk group, ask your clinician or clinic now where to go if flu starts.
- For work or school rules about staying home with flu, check with your employer or your local health department.
By MeridianMedicalCentre.com Health Research Team