Cold, Flu, or COVID? How to Tell the Difference This Autumn

As temperatures drop and terraces fill with scarves instead of sunglasses, a familiar question starts to circulate in Barcelona: “Do I have a cold, the flu… or COVID?”

Every autumn, my clinic sees a surge in patients , both tourists and expats , who arrive worried about fever, cough, and fatigue. The symptoms can look deceptively similar, yet the causes (and the level of concern) are very different.

For travelers and international residents, the confusion is even greater. Long flights, jet lag, and climate changes can all weaken the immune system, making it harder to distinguish one infection from another.

In this article, I’ll explain how to tell the difference between a common cold, influenza, and COVID-19, what symptoms to watch for, and when it’s best to see a doctor during your stay in Barcelona.

Why it’s easy to mix them up

Viruses thrive in autumn. As humidity rises and people spend more time indoors, respiratory infections spread rapidly. Schools reopen, offices fill up, and the air-conditioning systems that once kept summer heat at bay now circulate germs.

To make things more complicated, cold viruses (rhinoviruses), flu viruses (influenza), and SARS-CoV-2 (COVID-19) all target the same system , your respiratory tract. They cause overlapping symptoms: fever, cough, sore throat, fatigue, and nasal congestion.

But there are important differences in how these illnesses begin, progress, and respond to treatment.

Cold, flu, or COVID: key symptom differences

Symptom	Common Cold	Flu (Influenza)	COVID-19
Onset	Gradual	Sudden	Gradual or sudden
Fever	Rare or mild	High (38–40°C)	Common, moderate
Body aches	Mild	Severe	Common, can persist
Cough	Mild, productive	Dry, strong	Dry or variable
Fatigue	Mild	Strong	Strong, long-lasting
Loss of smell/taste	Rare	Rare	Common early symptom
Headache	Occasional	Frequent	Frequent
Sore throat	Common	Common	Possible
Shortness of breath	No	Rare	Possible, especially in older adults
Duration	5–7 days	1–2 weeks	Variable (can last >2 weeks)

How to identify what you have

1) If your symptoms develop slowly and stay mild:

You likely have a common cold. Rest, hydration, and paracetamol/ibuprofen for discomfort are usually enough. Antibiotics don’t help, since the cause is viral.

2) If your symptoms hit suddenly with fever and muscle pain:

It’s probably influenza. Flu tends to make you feel “knocked out” quickly. Appetite disappears, the body aches, and fatigue is intense. In these cases, vaccination is the best prevention , but if you didn’t get one, treatment focuses on rest, fluids, and fever control.

3) If you have fatigue, cough, fever, or loss of smell/taste:

You should consider COVID-19 and take a test. Rapid antigen tests are widely available in Barcelona pharmacies for a few euros. If you test positive, isolate and contact a healthcare provider for guidance, especially if you have risk factors or travel plans.

When to see a doctor

Regardless of the cause, certain symptoms warrant medical evaluation , especially when you’re abroad:

• Fever above 38.5°C for more than 48 hours

• Difficulty breathing or chest tightness

• Persistent vomiting or dehydration

• Dizziness or confusion

• Severe sore throat with swollen glands

• Wheezing (particularly if you have asthma or allergies)

In these cases, a private consultation provides quick relief and proper medical documentation for insurance or travel needs.

COVID-19 in Barcelona: what you should know (2025 update)

While COVID-19 is no longer a global emergency, the virus still circulates seasonally. Spain’s healthcare system now treats it as an endemic infection, similar to influenza. However, testing and travel policies may still vary depending on airlines or countries of destination.

Testing options in Barcelona:

• Pharmacies: sell self-test kits (rapid antigen) for 2–5€.

• Private clinics: offer certified antigen or PCR tests with official reports in English for flights, schools, or workplaces.

If you test positive:

• Rest, hydrate, and monitor your symptoms.

• Seek medical help if you experience shortness of breath, confusion, or worsening fever.

• Most mild cases recover within 5–10 days.

How to manage mild symptoms at home or your hotel

• Hydrate well: water, herbal teas, and soups help loosen mucus.

• Rest: your immune system needs energy to fight infection.

• Use a humidifier: Barcelona’s autumn air can be dry indoors.

• Take paracetamol or ibuprofen for fever and discomfort.

• Avoid alcohol and smoking, which irritate airways.

• Ventilate rooms daily.

If you’re staying in a hotel or Airbnb, many pharmacies can deliver basic medications directly to you.

Why early medical assessment helps

For tourists, expats, or international students, getting an early diagnosis can prevent complications and save valuable time.

A doctor can:

• Confirm the cause (flu, COVID, or another respiratory infection).

• Issue medical certificates for work, school, or insurance.

• Prescribe antivirals or antibiotics when indicated.

• Provide documentation for flight changes or travel claims.

Public health centers (CAPs) may take days to provide an appointment. Private clinics, like mine, offer same-day consultations in multiple languages, minimizing disruption to your trip or work schedule.

FAQs

Can I get both the flu and COVID vaccines? Yes, safely , even on the same day. Many clinics offer both in autumn.

Do I need to isolate if I test positive for COVID in Spain? Isolation is no longer mandatory, but recommended for at least 5 days if you have fever or cough.

How long should I rest before flying? Avoid traveling with fever or fatigue. Airlines can deny boarding to visibly ill passengers.

What about antibiotics? They only work for bacterial infections. Using them unnecessarily can cause resistance and side effects.

Should I worry if my cough lasts after recovery? A mild cough can persist for 2–3 weeks after viral infections. If it worsens or is accompanied by fever, see a doctor.

Final thoughts

Autumn in Barcelona is beautiful , but it’s also virus season. Whether you’re here for business, study, or leisure, understanding the difference between a cold, flu, and COVID helps you stay calm and make smart decisions.

If you feel unwell, don’t wait in long public queues or struggle with language barriers. Private medical care offers immediate diagnosis, treatment, and the reassurance you need to recover quickly and enjoy your time in Barcelona.

About the author

Dr. Stefan Botnar, MD – English Speaking Doctor in Barcelona for Tourists

Dr. Stefan Botnar is a board-certified English-speaking doctor in Barcelona with over 15 years of experience in internal medicine and public health. He provides fast, out-of-pocket consultations for international patients, specializing in preventive care, substance metabolism, travel-related issues, and especially STD/ETS testing and treatment.

His clinic, located at Carrer de la Marina, 16–18, Torre Mapfre, Barcelona, offers in-person and telemedicine appointments, immunizations, nutritional advice, and minor emergency care (fever, gastroenteritis, allergic reactions). Patients pay directly, no insurers required.

Dr. Botnar speaks English, Spanish, Russian, Romanian, and German, ensuring clear communication with a diverse tourist clientele. He delivers evidence-based diagnoses and tailored treatment plans, helping visitors prevent common ailments (heatstroke, food poisoning) and offering comprehensive follow-up until they return home.

As a specialist in internal medicine, Dr. Botnar also focuses on the mind-body connection, supporting patients in navigating seasonal transitions and maintaining balance while traveling.

Disclaimer

 This article is for informational purposes only and is not a substitute for professional medical advice. Always consult a healthcare provider if you experience persistent or worsening symptoms.