When you’re feeling sick, it can be frustrating to figure out if you have a cold, the flu, or COVID-19. These illnesses share overlapping signs, but there are differences in how they show up, how long they last, and how serious they can become. Knowing the distinctions helps you understand what you might be facing and when to consider testing or medical care.
What Causes Each Illness?
- Common Cold: Caused by many viruses, most often rhinoviruses, colds are typically mild and short-lived.
- Flu (Influenza): The flu is caused by influenza viruses, which tend to strike suddenly and can bring more severe symptoms than a cold.
- COVID-19: Caused by the SARS-CoV-2 virus, COVID-19 can mimic flu or cold symptoms but may also involve unique signs like loss of taste or smell and has a higher chance of serious complications.
Symptom Breakdown
Cold Symptoms
The common cold tends to build gradually and often feels like an annoyance more than a serious illness. Typical symptoms of the common cold include:¹
- Runny or stuffy nose
- Sneezing
- Headache
- Sore throat
- Cough
Symptoms usually improve within 10-14 days.
Flu Symptoms
The flu usually develops suddenly and can leave you feeling drained. Compared to a cold, the flu tends to hit harder and keep you in bed for several days. Most people who have the flu experience:²
- Fever
- Body aches and chills
- Runny nose or congestion
- Headache
- Moderate to severe fatigue
- Cough and sore throat
- Nausea
Symptoms often last 5–7 days, though tiredness may stick around a bit longer.
COVID-19 Symptoms
COVID-19 shares many similar symptoms with colds and the flu, but it can also include distinctive signs. Some cases are mild, while others become serious enough to require hospitalization. Common symptoms include:³
- Fever
- Chills
- Dry cough
- Loss of taste or smell
- Shortness of breath
- Sore throat
- Headache
- Congestion
- Sometimes nausea, diarrhea, or vomiting
Symptoms may last up to 14 days or longer, depending on severity.
Severity and Higher Risk
Colds are almost always mild and rarely cause complications. The flu, however, can lead to pneumonia or worsening of chronic conditions, especially in children 6 months and older, older adults, and those with weaker immune systems.
COVID carries the greatest uncertainty, with potential for long-term effects and more severe illness in people at higher risk, such as those with underlying medical conditions or compromised immunity.
Testing and Diagnosis
Because of overlapping similar symptoms, it can be hard to know which illness you have without testing.
- Cold: No specific test; diagnosed by symptoms
- Flu: Confirmed through rapid flu testing²
- COVID-19: Confirmed with rapid antigen or PCR testing⁴
Treatment Options
Each illness is managed differently, but most cases improve with rest and supportive care.
- Common cold: Rest, hydration, and over-the-counter medications for congestion or cough.¹
- Flu: Prescription antivirals may shorten recovery if started early.²
- COVID-19: Antiviral medications may be recommended for those at higher risk, along with rest and monitoring symptoms.⁵
Prevention
Because these illnesses spread in similar ways, the steps to reduce risk overlap. Frequent handwashing, covering your mouth when coughing or sneezing, and staying home when sick can reduce transmission.
Vaccines also play a key role. The yearly flu shot helps lower the chances of catching or spreading influenza, and updated COVID-19 vaccines help protect against severe outcomes. A strong immune system, supported by good nutrition, regular exercise, and enough sleep, further reduces your vulnerability.
Frequently Asked Questions
How do I know if it's COVID-19, a cold, or the flu?
The only way to know for sure is through testing, since the symptoms overlap. Colds are usually mild with congestion and sneezing, the flu tends to come on suddenly with fever and body aches, and COVID can include loss of taste or smell or symptoms that last longer.¹,²,³
Does COVID feel worse than the flu?
COVID can sometimes feel worse than the flu because it may last longer and cause shortness of breath or fatigue that lingers. However, severity varies widely, and some cases are mild.
Does COVID start with sneezing?
Sneezing is not a typical first sign of COVID. Early symptoms are more likely to include fever, cough, or loss of taste and smell.³
When to Seek Medical Help
Most people recover from these illnesses at home, but sometimes symptoms become more serious. You should seek medical attention if you experience difficulty breathing, persistent chest pain, confusion, or dehydration. A high fever that doesn’t improve or extreme fatigue are also warning signs.
This is especially important for people at higher risk, such as older adults, young children, or those with chronic medical conditions. When in doubt, getting checked by a healthcare professional is the safest option.
Get Care Without Leaving Home
Sorting out the differences between a cold, the flu, and COVID-19 can be confusing, but relief doesn’t have to wait.
At 24hrdoc, our online doctors are available to evaluate your symptoms and provide treatment for common issues like sore throat, cough, and congestion, as well as conditions such as cold and flu. With fast virtual visits and prescriptions sent directly to your pharmacy, you can focus on feeling better without the hassle of an in-person appointment. Start feeling better today.
Sources:
- MedlinePlus. Common Cold.
- MedlinePlus. Flu.
- WebMD. Symptoms of Coronavirus.
- MedlinePlus. COVID-19 Testing.
- CDC. Types of COVID-19 Treatment.
Share to
