COVID-19 causes a wide range of symptoms that overlap heavily with the common cold and flu. The most frequently reported signs include fever, cough, fatigue, sore throat, runny or stuffy nose, body aches, and headache. Some people also lose their sense of taste or smell, and about one in four experience digestive issues like nausea or diarrhea. Symptoms typically appear 2 to 14 days after exposure.
The Most Common Symptoms
COVID-19 can look different from person to person, but the core symptoms are respiratory. A dry cough, sore throat, congestion, and fatigue show up in the majority of cases. Fever is common but not universal. Headaches and body aches round out the typical picture, making it easy to mistake for other respiratory infections early on.
Loss of taste or smell was once considered a hallmark of COVID-19 and remains one of its more distinctive features. It often appears early in the illness, sometimes without any nasal congestion at all. This sets it apart from a cold, where you might lose smell simply because your nose is blocked.
Shortness of breath can develop in some cases, particularly a few days into the illness. It doesn’t happen to everyone, but when it does, it signals that the infection is affecting the lungs more significantly.
Digestive and Less Obvious Symptoms
Not everyone with COVID-19 has a cough or sore throat. In a large analysis of more than 72,000 cases from China, roughly 10% of patients had gastrointestinal symptoms as a prominent feature. Diarrhea appeared in 2 to 10% of cases, and nausea or vomiting in a similar range. When loss of appetite is included, the overall rate of digestive involvement climbs to about 20 to 25%. Some people experience stomach issues before any respiratory symptoms show up, which can delay recognition.
How It Differs From a Cold or Flu
The biggest challenge with COVID-19 is that its symptoms overlap with several other illnesses. Here’s how to tell them apart based on patterns identified by the Mayo Clinic:
- Timing: Cold symptoms appear 1 to 3 days after exposure. Flu symptoms show up in 1 to 4 days. COVID-19 has a wider window of 2 to 14 days, so if symptoms start a week or more after a known exposure, COVID is more likely than a cold.
- Fever: The flu almost always causes a fever. Colds rarely do. COVID-19 falls in between, with fever appearing in many but not all cases.
- Loss of taste or smell: This is uncommon with a cold (where it only happens from congestion) and rare with the flu. With COVID-19, it can appear early and without a stuffy nose.
- Shortness of breath: Colds don’t cause it. Both COVID-19 and the flu can, but it tends to be more prominent with COVID-19.
- Cough type: COVID-19 typically produces a dry cough rather than a wet, productive one.
None of these differences are reliable enough on their own. The only sure way to distinguish COVID-19 from the flu or a cold is a test.
How Long Symptoms Last
For mild to moderate cases, active illness typically lasts one to two weeks. Most people start to feel better within 7 to 10 days, with fatigue often lingering a few days longer than other symptoms. Severe cases can stretch out for months, sometimes requiring hospitalization and a longer recovery period. Vaccination and prior infection generally shorten the course, largely because your immune system recognizes the virus faster.
Some people continue to experience fatigue, brain fog, or other symptoms weeks or months after the initial infection. This is commonly referred to as long COVID, and it can occur even after a mild case.
Symptoms in Children
Children generally get milder illness than adults, but they’re not immune. The most common symptoms in kids are fever and cough, including a barking cough linked to croup. Sore throat, runny nose, fatigue, headache, and digestive symptoms like vomiting and diarrhea also appear frequently. For many children, COVID-19 looks identical to any other respiratory illness.
A rare but serious complication called Multisystem Inflammatory Syndrome in Children (MIS-C) can develop weeks after infection. It involves a persistent fever along with vomiting, diarrhea, belly pain, skin rash, and bloodshot eyes. Warning signs that require emergency care include difficulty breathing, new confusion, inability to stay awake, severe belly pain, and gray or blue discoloration of the skin, lips, or nail beds.
Do Newer Variants Cause Different Symptoms?
As of recent variants, including the FLiRT subvariants tracked in 2024, the symptom profile has not meaningfully changed. Researchers at Johns Hopkins note that while cases tend to produce milder illness overall, that’s likely not because the virus itself has become gentler. Rather, widespread immunity from vaccination and prior infections means most people’s bodies mount a faster defense, keeping symptoms in check.
The core symptoms remain the same across variants: fever, cough, sore throat, fatigue, congestion, and body aches. There’s no evidence that any current strain causes a unique or unusual set of symptoms compared to earlier versions of omicron.
Emergency Warning Signs
Most people recover at home without complications. But certain symptoms signal that the body is struggling and needs immediate medical attention. The CDC identifies these emergency warning signs:
- Trouble breathing: Not just a stuffy nose, but genuine difficulty getting air.
- Persistent chest pain or pressure: A feeling that doesn’t go away with rest or position changes.
- New confusion: Difficulty thinking clearly that wasn’t present before the illness.
- Inability to wake or stay awake: Extreme drowsiness beyond normal fatigue.
- Color changes in lips, nail beds, or skin: Pale, gray, or bluish tones, which may look different depending on skin tone and can indicate low oxygen levels.
If any of these develop, call 911 or your local emergency number. Let them know that COVID-19 is suspected so the care team can prepare.