COVID-19 most commonly causes headache, sore throat, fatigue, runny or stuffy nose, and cough. Symptoms typically appear 2 to 14 days after exposure and often start mild before potentially worsening. Most people recover within a week or two, but the illness can affect nearly every system in the body, and symptoms vary widely from person to person.
The Most Common Symptoms
Current variants of COVID-19 produce symptoms that overlap heavily with cold and flu. The most frequently reported signs include:
- Sore throat
- Headache
- Fatigue and body aches
- Runny or stuffy nose
- Cough (often dry)
- Fever or chills
- Sneezing
- Shortness of breath
Not everyone gets every symptom. Some people develop only a scratchy throat and mild fatigue, while others spike a high fever with body aches and a persistent cough. A small number of infected people never develop symptoms at all.
Loss of Taste and Smell
Early in the pandemic, losing your sense of taste or smell was a hallmark of COVID-19, affecting 44 to 72% of people infected with the original and earlier variants. That has changed significantly. With Omicron and its subvariants, only about 13 to 18% of people experience smell or taste changes. It still happens, and it remains more distinctive to COVID than to the flu or a cold, but it’s no longer the red flag it once was.
For most people, these senses return within a few weeks. A small percentage, however, experience lingering problems. A four-year follow-up study found that some people with smell loss from their initial infection still had measurable deficits years later, even when they felt their sense of smell had mostly returned.
Gut Symptoms Are More Common Than You Think
COVID-19 isn’t just a respiratory illness. Digestive symptoms show up in a substantial number of cases. Diarrhea affects roughly 10 to 34% of patients depending on the study, with U.S. data consistently showing higher rates than global averages. Nausea or vomiting occurs in about 10 to 26% of cases. Some people experience stomach pain or loss of appetite as their first or only noticeable symptom, which can delay testing because they don’t associate gut trouble with a respiratory virus.
These symptoms can appear alongside the typical cough and fever, or they can show up on their own. If you have unexplained digestive problems during a local surge, testing is worth considering.
How COVID Differs From the Flu and a Cold
The overlap between COVID, flu, and the common cold makes it nearly impossible to tell them apart based on symptoms alone. Testing is the only reliable way to know. That said, there are patterns that lean one direction or the other.
Headache, sore throat, fatigue, and a stuffy nose are common across all three illnesses. Fever is more reliable in flu, where it shows up in most cases, while COVID produces fever only sometimes. Muscle aches are a hallmark of the flu but only occasional with COVID. The most useful distinguishing feature is still loss of taste or smell: it’s common in COVID, rare with the flu, and essentially absent in a standard cold. Shortness of breath can occur with both COVID and the flu but is unusual with a cold.
Colds also tend to come on gradually, while both COVID and the flu can hit more suddenly. Flu symptoms often peak faster and include more intense body aches and chills in the first day or two.
Symptom Timeline
After exposure, symptoms can appear anywhere from 2 to 14 days later, though most people notice something within 3 to 5 days with current variants. The illness often follows a rough pattern: mild throat irritation and fatigue in the first day or two, followed by congestion, cough, and possible fever peaking around days 3 through 5. Most mild to moderate cases start improving by the end of the first week.
Some people feel better around day 5 or 6, then experience a secondary dip where symptoms temporarily worsen before resolving. This is more common in older adults and people with underlying health conditions. Cough and fatigue often linger the longest, sometimes persisting for two to three weeks after other symptoms have cleared.
Symptoms in Children
Children generally have milder COVID infections than adults. They commonly develop fever, cough, runny nose, and fatigue, and many recover quickly. Gut symptoms like diarrhea and vomiting tend to be more prominent in kids than in adults.
The main concern in children is a rare but serious condition called Multisystem Inflammatory Syndrome in Children (MIS-C), which can develop two to six weeks after a COVID infection. Warning signs include a persistent fever along with one or more of the following: stomach pain, vomiting, diarrhea, skin rash, or bloodshot eyes. Severe cases can cause trouble breathing, chest pain, confusion, or pale or blue-tinged skin. MIS-C is uncommon, but it requires emergency care.
Severe Symptoms That Need Immediate Attention
Most COVID infections resolve on their own, but a small percentage of cases progress to serious illness. Symptoms that signal a dangerous turn include difficulty breathing or shortness of breath at rest, persistent pain or pressure in the chest, new confusion or inability to stay awake, and pale, gray, or blue-colored lips or skin. These can indicate that the lungs, heart, or other organs are under significant stress.
The risk of severe disease is highest for adults over 65, people with chronic conditions like diabetes, heart disease, or lung disease, and those with weakened immune systems.
When Symptoms Don’t Go Away: Long COVID
Long COVID is defined as symptoms that persist for at least three months after infection. It can develop after even a mild initial illness, and it affects multiple body systems. The most commonly reported long-term symptoms include crushing fatigue that doesn’t improve with rest, brain fog and difficulty concentrating, shortness of breath, heart palpitations, joint or muscle pain, sleep disturbances, and ongoing digestive issues.
These symptoms can fluctuate over time, improving for weeks and then flaring again. Some people recover fully within six months to a year, while others deal with symptoms much longer. Long COVID appears to be less common with newer variants and in people who were vaccinated before infection, though it still occurs in both groups.
How Vaccination Affects Symptoms
Vaccinated people who catch COVID (breakthrough infections) are significantly less likely to develop symptoms in the first place. In one large study, only about 27% of vaccinated participants had symptomatic infections compared to 73% of unvaccinated participants. When vaccinated people do get sick, the illness tends to be shorter and the risk of hospitalization is lower.
The specific symptoms themselves are largely the same regardless of vaccination status. Headache, body aches, runny nose, and loss of taste or smell show up at similar rates in both groups. The main benefit of vaccination is reducing the chance that a mild case becomes a severe one.