Evidence-based|Sources: NIH, WHO, AHA, AGS clinical guidelines|Updated 2026

What is seasonal influenza?

In short A contagious viral infection that attacks the nose, throat, and lungs. In older adults it can progress quickly to pneumonia, worsen heart failure or COPD, and increase stroke or heart attack risk in the weeks after infection.

Key window: Antiviral medicines work best if started within the first 48 hours of symptoms—earlier is better.

Typical symptoms in older adults

  • Sudden fever or feeling feverish/chills (fever may be mild/absent in seniors)
  • Dry cough, sore throat, runny/stuffy nose
  • Headache, muscle or body aches, extreme tiredness
  • Shortness of breath, chest tightness, wheeze (especially with COPD/asthma)
  • Confusion, dizziness, poor appetite, or falls (common atypical signs)

When to seek urgent care

  • Blue/gray lips, severe shortness of breath, chest pain, or new confusion
  • High fever that won’t settle, repeated vomiting, inability to drink/pee
  • Symptoms improving then suddenly worse (secondary pneumonia)
  • Worsening COPD/asthma or heart failure signs (swelling, breathlessness)

Call your local emergency number if these occur.

Who is at higher risk

  • Age ≥65, frailty, nursing-home residence
  • Heart or lung disease (CHF, CAD, COPD, asthma)
  • Diabetes, kidney disease, neurological conditions, obesity
  • Weakened immunity or cancer treatment
If you’re high risk and develop flu-like illness, contact your clinician as soon as possible—don’t wait for severe symptoms.

Testing: when and how

When to test

  • Within the first 1–2 days of symptoms (or anytime for those very ill/hospitalized)
  • During local outbreaks or flu season with typical symptoms

How testing is done

  • Rapid antigen or PCR swab from nose/throat
  • Some clinics test for both flu & COVID at once

Treatment (antivirals)

Start early

  • Antivirals work best if started within 48 hours of symptoms—may still help later in severe or high-risk cases
  • Common options: oseltamivir (pill), baloxavir (single dose), or inhaled zanamivir (not for severe lung disease)

Safety & adjustments

  • Kidney disease often requires dose changes—review with your clinician
  • Watch for nausea or neuropsychiatric effects; report unusual symptoms
  • Continue usual heart, lung, and diabetes medicines unless told otherwise
Antibiotics don’t treat flu, but may be needed if bacterial pneumonia is suspected.

Home care & hydration

Fluids & fever

  • Small frequent sips; oral rehydration or broths if appetite is low
  • Acetaminophen for fever/aches if approved for you; avoid duplicate products

Breathing & rest

  • Head-of-bed elevation, paced breathing; use prescribed inhalers correctly
  • Light activity between rests to reduce deconditioning and clots risk

Reduce spread

  • Stay home until fever-free for 24 hours without fever-reducers
  • Mask around others, open windows, clean high-touch surfaces

Vaccines & prevention

Best timing

  • Get vaccinated each season—ideally before local circulation increases
  • Protection builds over ~2 weeks after the shot

Vaccine types for 65+

TypeWhat’s differentNotes
High-dose inactivated More antigen Designed to produce a stronger immune response in seniors
Adjuvanted inactivated Immune booster (adjuvant) Another good option for ≥65
Standard-dose Regular antigen amount Use if high-dose/adjuvanted not available—don’t delay vaccination

Around the home

  • Caregivers and family members should be vaccinated
  • Wash hands, cover coughs, and ventilate rooms

Flu vs. cold vs. COVID

FeatureFluCommon coldCOVID-19
OnsetSuddenGradualVaries
Fever/achesCommon, prominentMildCommon
CoughDry, bothersomeMild–moderateCommon
Taste/smell lossUncommonUncommonMore common
TestingFlu swabUsually noneCOVID test

Because symptoms overlap, combined testing may be recommended.

Quick answers

Do I still need the shot if I had flu last year?

Yes—viruses change and immunity fades. Get vaccinated every season.

Can I take antivirals if I also have COVID?

Yes—your clinician may treat both, depending on timing and risk. Bring a full medication list to check interactions.

How long am I contagious?

From about a day before symptoms until at least 5–7 days after they start—longer if very ill or immunocompromised.

Egg allergy and the vaccine?

Most people with egg allergy can get any age-appropriate flu vaccine; ensure vaccination is in a setting that can manage rare reactions.

Medical DisclaimerThis article is for educational purposes only and is not a substitute for professional medical advice. Always consult your doctor before starting supplements or changing medications. Learn about our editorial process.
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