The symptoms of COVID-19 are variable depending on the type of variant contracted, ranging from mild symptoms to a potentially fatal illness. Common symptoms include coughing, fever, loss of smell and taste, with less common ones including headaches, nasal congestion and runny nose, muscle pain, sore throat, diarrhea, eye irritation, and toes swelling or turning purple, and in moderate to severe cases, breathing difficulties. People with the COVID-19 infection may have different symptoms, and their symptoms may change over time.

Three common clusters of symptoms have been identified: a respiratory symptom cluster with cough, sputum, shortness of breath, and fever; a musculoskeletal symptom cluster with muscle and joint pain, headache, and fatigue; and a cluster of digestive symptoms with abdominal pain, vomiting, and diarrhea. In people without prior ear, nose, or throat disorders, loss of taste combined with loss of smell is associated with COVID-19 and is reported in as many as 88% of symptomatic cases.

Of those who show symptoms, 81% develop only mild to moderate symptoms (up to mild pneumonia), while 14% develop severe symptoms (dyspnea, hypoxia, or more than 50% lung involvement on imaging) that require hospitalization, and 5% of patients develop critical symptoms (respiratory failure, septic shock, or multiorgan dysfunction) requiring ICU admission. As of 2024–2025, the majority of infections are characterized as mild or asymptomatic; however, risk remains stratified by age and underlying health conditions, with severe outcomes—including respiratory failure and multi-organ dysfunction—occurring in a significantly smaller percentage of the general vaccinated population than in early 2020.

At least a third of the people who are infected with the virus do not develop noticeable symptoms at any point in time.Multiple sources:

These asymptomatic carriers tend not to get tested and can still spread the disease. Other infected people will develop symptoms later (called "pre-symptomatic") or have very mild symptoms and can also spread the virus.

As is common with infections, there is a delay, or incubation period, between the moment a person first becomes infected and the appearance of the first symptoms. The median delay for COVID-19 is four to five days possibly being infectious on 1–4 of those days. Most symptomatic people experience symptoms within two to seven days after exposure, and almost all will experience at least one symptom within 12 days.

Most people recover from the acute phase of the disease. However, some people continue to experience a range of effects, such as fatigue, for prolonged periods after an initial COVID-19 infection. This is the result of a condition called long COVID, which can be described as a range of persistent symptoms that continue for months or years. Long-term damage to organs has been observed after the onset of COVID-19. Multi-year studies are underway to further investigate the protracted effects of long COVID. Reducing the risk of long COVID includes staying up to date on the most recent COVID-19 vaccine, practicing good hygiene, maintaining clean indoor air, and physical distancing from people infected with a respiratory virus.

The Omicron variant became dominant in the U.S. in December 2021. Symptoms with the Omicron variant are less severe than they are with other variants.

Overview

Some less common symptoms of COVID-19 can be relatively non-specific; however the most common symptoms are fever, dry cough, and loss of taste and smell. Among those who develop symptoms, approximately one in five may become more seriously ill and have difficulty in breathing. Emergency symptoms include difficulty in breathing, persistent chest pain or pressure, sudden confusion, loss of mobility and speech, and bluish face or lips; immediate medical attention is advised if these symptoms are present. Further development of the disease can lead to complications including pneumonia, acute respiratory distress syndrome, sepsis, septic shock, and kidney failure.

Some symptoms usually appear sooner than others, with deterioration usually developing in the second week. In August 2020, scientists at the University of Southern California reported the "likely" order of initial symptoms of the COVID-19 disease as a fever followed by a cough, then sore throat, muscle pain, or headache, followed by nausea, vomiting, and diarrhea. This contrasts with the most common path for influenza where it is common to develop a cough first and fever later. Impaired immunity in part drive disease progression after SARS-CoV-2 infection. While health agency guidelines tend to recommend isolating for 14 days while watching for symptoms to develop, there is limited evidence that symptoms may develop for some patients more than 14 days after initial exposure.

Symptom profile of variants

The frequency of symptoms predominating for people with different variants may differ from what was observed in the earlier phases of the pandemic.

Delta Infection with the Delta variant causes flu-like symptoms. Common symptoms include fever, coughing, headache, shortness of breath, muscle pain, and weakness. Most people also experience numbness or loss of one's senses of smell and taste. In severe cases, symptoms include difficulty breathing, low oxygen levels in blood, acute respiratory distress syndrome, septic shock, increased blood acidity, coagulation dysfunction, and failure of multiple organs.

Omicron

British epidemiologist Tim Spector said in mid-December 2021 that the majority of symptoms of the Omicron variant were the same as a common cold, including headaches, sore throat, runny nose, fatigue and sneezing, so that people with cold symptoms should take a test. "Things like fever, cough and loss of smell are now in the minority of symptoms we are seeing. Most people don't have classic symptoms." People with cold symptoms in London (where Covid was spreading rapidly) are "far more likely" to have Covid than a cold.

A unique reported symptom of the Omicron variant is night sweats, particularly with the BA.5 subvariant. Also, loss of taste and smell seem to be uncommon compared to other strains.

Systemic Typical systemic symptoms include fatigue, and muscle and joint pains. Some people have a sore throat.Hoarseness and a dry or irritated throat have also been reported as symptoms, especially for patients infected with the XFG strain.

Fever Fever is one of the most common symptoms in COVID-19 patients. However, the absence of the symptom itself at an initial screening does not rule out COVID-19. Fever in the first week of a COVID-19 infection is part of the body's natural immune response; however in severe cases, if the infections develop into a cytokine storm the fever is counterproductive. As of September 2020, little research had focused on relating fever intensity to outcomes.

A June 2020 systematic review reported a 75–81% prevalence of fever. As of July 2020, the European Centre for Disease Prevention and Control (ECDC) reported a prevalence rate of ~45% for fever.

Pain A June 2020 systematic review reported a 27–35% prevalence of fatigue, 14–19% for muscle pain, 10–14% for sore throat. As of July 2020, the ECDC reported a prevalence rate of ~63% for muscle weakness (asthenia), ~63% for muscle pain (myalgia), and ~53% for sore throat.

Respiratory Coughing is another typical symptom of COVID-19, which could be either dry or a productive cough.

Some symptoms, such as difficulty breathing, are more common in patients who need hospital care. Shortness of breath tends to develop later in the illness. Persistent anosmia or hyposmia or ageusia or dysgeusia has been documented in 20% of cases for longer than 30 days.

Respiratory complications may include pneumonia and acute respiratory distress syndrome (ARDS).

As of July 2020, the ECDC reported a prevalence rate of ~68% for nasal obstruction, ~63% for cough, ~60% for rhinorrhoea or runny nose.A June 2020 systematic review reported a 54–61% prevalence of dry cough and 22–28% for productive cough.

Cardiovascular Coagulopathy is established to be associated with COVID-19 in those patients in critical state. Thromboembolic events, such as blood clots show with high risk in COVID-19 patients in some studies.

Other cardiovascular complications may include heart failure, arrhythmias, and heart inflammation. They are common traits in severe COVID-19 patients due to the relation with the respiratory system.

Hypertension seems to be the most prevalent risk factor for myocardial injury in COVID-19 disease. It was reported in 58% of individuals with cardiac injury in a recent meta-analysis.

Several cases of acute myocarditis associated with COVID-19 have been described around the globe and are diagnosed in multiple ways. Taking into consideration serology, leukocytosis with neutrophilia and lymphopenia was found in many patients. Cardiac biomarkers troponin and N-terminal (NT)-prohormone BNP (NT-proBNP) were seen elevated. Similarly, the level of inflammation-related markers such as C-reactive protein (CRP), D-dimer, IL-6, procalcitonin was significantly increased, indicating an inflammatory process in the body. Electrocardiogram findings were variable and ranged from sinus tachycardia, ST-segment elevation, T-wave inversion and ST-depression. In one case, viral particles were seen in the interstitial cell, and another case reported SARS-CoV-2 RT–PCR positivity in the cardiac tissue suggestive of direct viral injury to the myocardium. Endomyocardial biopsy [EMB] remains the gold standard invasive technique in diagnosing myocarditis; however, due to the increased risk of infection, it is not done in COVID-19 patients.

The binding of the SARS-CoV-2 virus through ACE2 receptors present in heart tissue may be responsible for direct viral injury leading to myocarditis. In a study done during the SARS outbreak, SARS virus RNA was ascertained in the autopsy of heart specimens in 35% of the patients who died due to SARS. It was also observed that an already diseased heart has increased expression of ACE2 receptor contrasted to healthy individuals. Hyperactive immune responses in COVID-19 Patients may lead to the initiation of the cytokine storm. This excess release of cytokines may lead to myocardial injury.

Neurological

Patients with COVID-19 can present with neurological symptoms that can be broadly divided into central nervous system involvement, such as headache, dizziness, altered mental state, and disorientation, and peripheral nervous system involvement, such as anosmia and dysgeusia. As was noted, COVID-19 has also been linked to various neurological symptoms at the diagnosis or throughout the disease, with over 90% of individuals with COVID-19 having reported at least one subjective neurological symptom. Some patients experience cognitive dysfunction called "", or "COVID brain fog", involving memory loss, inattention, poor concentration or disorientation. Other neurologic manifestations include seizures, strokes, encephalitis, and Guillain–Barré syndrome (which includes loss of motor functions).

As of July 2020, the ECDC reported a prevalence rate of ~70% for headache. A June 2020 systematic review reported a 10–16% prevalence of headache. However, headache could be mistaken for having a random relationship with COVID-19; there is unambiguous evidence that COVID-19 patients who had never had a recurrent headache suddenly get a severe headache daily because of SARS-CoV-2 infection.

Loss of smell

In about 60% of COVID-19 patients, chemosensory deficits are reported, including losing their sense of smell, either partially or fully.