What is the flu?
The flu, or influenza, is a contagious respiratory illness caused by influenza viruses that infect the nose, throat, and sometimes the lungs. It's usually seasonal, with flu season in Mexico and much of the Northern Hemisphere running roughly from October to May, and typically peaking between December and February.
Visiting Puerto Vallarta and feeling flu symptoms?
Our bilingual medical team offers testing, treatment, and flu shots — 24/7 urgent care available.
What are the symptoms of the flu?
Flu symptoms usually come on suddenly and can include:
- Fever or feeling feverish (not everyone with the flu runs a fever)
- Cough, often dry and persistent
- Sore throat
- Runny or stuffy nose
- Body aches and headache
- Chills and sweats
- Fatigue
Unlike a cold, which usually comes on gradually, the flu tends to hit hard and fast — it's common to feel fine one day and quite unwell the next.
Flu vs. cold vs. COVID-19: what's the difference?
| Symptom | Flu | Common cold | COVID-19 |
| Onset | Sudden | Gradual | 2-14 days after exposure |
| Fever | Common, can be high | Rare | Common |
| Body aches | Common, often severe | Mild | Common |
| Loss of taste/smell | Rare | Rare | Common |
| Severity | Can be severe | Usually mild | Can be severe |
Because these illnesses share so many symptoms, testing is the only reliable way to know which one you have — especially important if you're in a higher-risk group.
How long does the flu last?
Most people recover within one to two weeks. Fatigue and a lingering cough can sometimes last a bit longer. Antiviral medication, if started within 48 hours of symptom onset, can shorten how long you're sick and reduce the risk of complications.
How is the flu treated?
- Rest and plenty of fluids — water, broths, and electrolyte drinks; avoid sugary or caffeinated drinks
- Over-the-counter medication for fever and body aches
- Antiviral medication, prescribed by a doctor, most effective when started within 48 hours of symptoms starting
- A humidifier and warm fluids can help ease a stuffy nose and sore throat
When should I see a doctor?
Seek medical care right away if you experience:
- Difficulty breathing or shortness of breath
- Chest pain
- Persistent dizziness
- A fever above 104°F (40°C)
- Symptoms that improve and then come back or get worse
- Worsening of an existing chronic condition
You're also at higher risk of flu complications if you're pregnant, over 65, under 5 years old, or have a chronic condition such as asthma, diabetes, or heart disease — contact your doctor as soon as symptoms begin.
Can the flu be prevented?
- Get a yearly flu shot — it takes about two weeks to provide full protection, so getting it before flu season starts is ideal
- Wash your hands often with soap and water for at least 20 seconds
- Cover coughs and sneezes with a tissue or your elbow
- Avoid close contact with people who are sick, and stay home if you're sick yourself
Flu care and vaccination at Hospital CMQ
Whether you are a resident or visiting Puerto Vallarta, our bilingual team can test for the flu, prescribe treatment, and administer flu shots.
Book via WhatsApp at +52 322 147 0044 or visit our Urgent Care, open 24/7.
Medically reviewed by Itzel Aguayo, MD
Last reviewed on 12/07/2026
The information provided in this article is for educational purposes only and should not be used as a substitute for professional medical advice.
Reading time: 4 minutes
References
- Centers for Disease Control and Prevention (CDC) — Flu Signs and Symptoms.
- Mayo Clinic. Influenza (flu): symptoms and causes.