A stuffy nose, cough and fever cannot establish a diagnosis on their own. In September, you may have an ordinary cold, flu or COVID-19, and the three overlap enough that “how I feel” is not a reliable way to tell them apart. A runny or blocked nose more often points towards a cold, while a very sudden onset with chills, muscle aches and exhaustion points towards flu. COVID-19 can resemble either; testing remains the only way to confirm it when the result would change what you do next.
September is not a medical test. Colds can occur in any month, and flu circulates throughout the year, even though its activity is generally more intense during the colder season. Therefore, it is not wise to rule out flu or COVID-19 simply because symptoms appeared in early autumn.
The important difference: symptoms can guide, but not confirm
The common cold is caused by many respiratory viruses, not a single agent. It is usually a milder upper respiratory tract infection: a blocked or runny nose, sneezing, throat discomfort and a moderate cough. Fever is less common in adults and, when present, tends to be lower. However, severity alone is not a sufficient criterion.
Flu more often has an onset people describe as “sudden”: they are functioning relatively normally during one part of the day, then fever or a feverish feeling, chills, muscle aches, headache and pronounced fatigue appear. The cough can be troublesome, and a stuffy nose does not rule out flu at all. Nor does the absence of fever completely rule it out.
COVID-19 can cause fever, chills, cough, sore throat, fatigue, headache, muscle aches and a stuffy or runny nose. A new change in or loss of smell or taste is more suggestive of COVID-19 than flu, but it does not occur in everyone who is infected. For this reason, health authorities emphasise that symptoms, taken separately or together, cannot reliably distinguish flu from COVID-19.
| Observed feature | More consistent with a cold | More consistent with flu | What to keep in mind about COVID-19 |
|---|---|---|---|
| Onset | Often gradual | Often sudden | May be gradual or sudden; it is not a confirming criterion |
| Stuffy nose, nasal discharge, sneezing | Very common | Possible, but sometimes less prominent | Can occur commonly and do not rule out infection |
| Fever and chills | Less common in adults | Common | Common, but variable |
| Muscle aches, exhaustion | Usually mild | Often pronounced | May be significant |
| New loss of smell or taste | Uncommon | Uncommon | May point towards COVID-19, but does not occur in all cases |
| Can it be confirmed from symptoms alone? | Not always | No | No; a test is needed |
The table is a guide, not a self-diagnosis tool. For example, a cold can cause fever, and flu can begin with an irritated throat and a stuffy nose. In children, older adults and people with chronic illnesses, the presentation may be even less “typical”.
Cough and fever are signs of a respiratory infection, not diagnostic labels
Cough occurs in all three situations. A dry cough does not confirm COVID-19, and a productive cough does not automatically confirm a bacterial infection. Likewise, fever shows that the body is responding to an infection or inflammation, but it does not reveal which virus caused it.
The most useful thing is to monitor the course of illness: when symptoms began, whether they worsen after an apparent improvement, whether breathing becomes difficult, and whether you can drink fluids and urinate normally. A fever or cough that improves and then returns or becomes more intense warrants a discussion with a doctor, especially if you also have lung, heart or metabolic disease.
When it is worth getting tested
Testing is more useful when the answer could change a decision: protecting a vulnerable person at home, obtaining a medical consultation in time, choosing treatment or limiting transmission at work, school or within the family. A doctor may recommend testing for COVID-19, flu or a test that can detect both.
Do not delay contacting your family doctor if you are in a category at higher risk of severe illness: you are over 65, pregnant, immunocompromised, or have asthma, chronic lung disease, diabetes, heart or kidney disease, or other significant conditions. Prescription antivirals are available for flu, and their benefit is greatest when treatment begins early, usually within the first one to two days after onset. The choice of treatment and the timing of testing are medical decisions, not reasons for self-medication.
If you have respiratory symptoms and care for, or are about to visit, an infant, a very elderly person or someone who is immunocompromised, handle the situation cautiously even before confirmation: avoid close contact, wear a well-fitting mask if you need to go out, and ventilate rooms.
What you can do at home in the first few days
- Stay home while you have a fever or feel noticeably unwell, and limit close contact with others.
- Resume activities only after your overall condition has improved and at least 24 hours have passed without fever, without fever-reducing medication. In the following days, reducing others’ exposure remains useful: ventilation, hand hygiene and a mask in crowded spaces or around vulnerable people.
- Drink fluids and rest. For fever or pain, ask a pharmacist or doctor for advice and follow the leaflet for the product you choose, including doses and contraindications.
- Do not take antibiotics “preventively”. Colds, flu and COVID-19 are viral infections; antibiotics do not treat them and may cause side effects or contribute to bacterial resistance. The risks of this practice are also explained in detail in the InfoBuz article on misuse of antibiotics and bacterial resistance.
Romania’s Ministry of Health advises people with respiratory symptoms to contact their family doctor to determine the appropriate course of action, wear a mask if travel in the community cannot be avoided, follow cough and sneeze hygiene, and ventilate enclosed spaces. These measures are useful regardless of whether the eventual diagnosis is a cold, flu or COVID-19.
Warning signs that should not wait
Seek medical help promptly if you develop difficulty breathing, persistent chest pain or pressure, confusion, unusual drowsiness, persistent dizziness, bluish-grey lips or face, significant signs of dehydration or rapid worsening. In adults, extreme weakness, inability to urinate, and fever or cough returning after a period of improvement are also signs that should be assessed.
In children, fast or difficult breathing, ribs pulling in when breathing, no tears, dry mouth, no urine for eight hours, seizures or a lack of their usual response to interaction are reasons for urgent assessment. For an infant younger than 12 weeks, any fever should be discussed promptly with a doctor.
For more information about fever, you can also read Mosquitoes and West Nile virus: how to protect yourself in summer and when to see a doctor, which provides complementary details on this topic.
To distinguish situations that require an emergency call from those that can begin with a family doctor, see the explanations in the InfoBuz guide to medical warning symptoms and calling 112.
The idea that prevents two common mistakes
The first mistake is to assume that a stuffy nose automatically means “just a cold”. The second is to focus solely on the name of the illness and ignore the person’s condition. For a young adult with no risk factors and mild symptoms that are improving, home care and measures to avoid passing the virus on may be enough. For someone vulnerable, with recent onset and fever, cough or feeling generally unwell, the same combination of symptoms may require testing and more prompt medical contact.
In short: flu tends to hit more abruptly, colds tend to involve the nose more and be milder, and COVID-19 can mimic both. Symptoms are clues; testing and medical assessment, when there is a risk of complications or an unfavourable course, are what provide clarity.
Frequently asked questions
Can you have flu without a fever?
Yes. Fever is common with flu, but it does not occur in everyone. The absence of fever does not rule out flu, especially if the onset was sudden and chills, muscle aches, cough and marked fatigue are present.
Does a stuffy nose rule out COVID-19?
No. A stuffy or runny nose can occur with COVID-19, flu and colds. It cannot be used alone to rule out or confirm any of these infections.
Why does quickly identifying flu matter for someone at risk?
Because a doctor can decide whether flu antivirals are indicated, and they usually work best when started early after symptoms begin. Do not start such treatments without medical advice.
Is it advisable to go to work if fever is gone after fever-reducing medication?
That is not a sufficient criterion. It is more prudent to return after symptoms have improved overall and at least 24 hours have passed without fever, without fever-reducing medication.
