Get the latest on how to schedule your COVID-19 vaccine, boosters and third doses, and more.
Updated Oct. 10, 2021
UC Davis Health is committed to providing you with the most up-to-date information on COVID-19 symptoms. Learn more about symptoms of COVID-19 and which can be the first indicators of illness:
COVID-19 symptoms may appear 2-14 days after exposure to the virus, according to the Center for Disease Control and Prevention (CDC). People with one or many of these symptoms in any combinations may have COVID-19:
While typical of COVID-19, these all may be symptoms of some other illness, too. Call your primary care provider if you have symptoms and believe you were in close contact with an infected person. You can also speak with a physician using Express Care or MyUCDavisHealth.
All of the variants, including omicron, cause similar symptoms, including cough, fever and fatigue. There is some evidence that fewer people with omicron are experiencing a loss of taste and smell. Omicron is also less likely to cause severe disease such as pneumonia that may require treatment in the hospital.
In fully vaccinated and/or boosted people, symptoms tend to be mild. In unvaccinated people, symptoms may be quite severe, possibly leading to hospitalization or even death.
Influenza (flu) and COVID-19 are both contagious respiratory illnesses and they have similar symptoms. It may be difficult to tell the difference based on symptoms alone, but there are three key differences, according to the CDC:
Symptoms of the common cold are usually mild. You could have a runny nose, cough, and sore throat. However, you won't have as much of a fever and likely won't feel as achy – both of which typically come with COVID-19 and the flu.
Learn more about the flu and how to get your flu shot from UC Davis Health
Most people who test positive for COVID-19 typically experience symptoms for a couple weeks. People who have long-haul COVID-19 symptoms, also called "long COVID," can experience health problems for four or more weeks after first being infected, according to the CDC.
The CDC says you should watch for these more sever symptoms, in which you should seek emergency medical attention:
**This is not a list of all possible severe symptoms. Call your health care provider for any symptoms that are concerning to you.
Most patients with omicron infection will have mild symptoms, especially those who are vaccinated with breakthrough infections. These patients may experience fever, cough, sore throat, fatigue, muscle pain and headache without progression to pneumonia.
People who are unvaccinated and are infected with omicron are at higher risk for the infection progressing to moderate or severe illness. This may result in pneumonia, difficulty breathing, and the need to be hospitalized for supplemental oxygen.
Typically, vaccinated people who test positive for COVID-19 are either asymptomatic or have very mild symptoms. It rarely results in hospitalization or death. Their symptoms are more like those of a common cold, such as cough, fever or headache, with the addition of significant loss of smell.
No vaccine is 100% effective. Health experts continue to see that the risk of infection, hospitalization, and death are much lower in vaccinated people compared to unvaccinated.
The earliest symptoms of COVID-19 will most likely be a fever, followed by a cough and muscle pain, according to a study by the University of Southern California. Next, infected people will possibly experience nausea or vomiting and diarrhea. Initial COVID-19 symptoms are similar to other respiratory illnesses such as MERS and SARS. However, patients with COVID-19 will likely develop nausea and vomiting before diarrhea, which is opposite from MERS and SARS, the USC researchers said.
If someone is showing these symptoms, you should seek emergency medical care immediately:
This is not a complete list of possibly symptoms. Call your primary care provider for any other symptoms that seem severe or are a concern to you.
Influenza (flu) and COVID-19 are both contagious respiratory illnesses and they have similar symptoms. It may be difficult to tell the difference based on symptoms alone, but there are two key differences, according to the CDC:
Learn about flu prevention and how to schedule your flu vaccine
Upper respiratory allergy symptoms typically include:
If these continue after exposure to something that usually triggers an allergy, or during the usual time of year you experience seasonal allergies, then it’s reasonable to attribute these symptoms to allergies rather than infection. But if there are other associated symptoms such as fever or cough – or they happen without the usual allergy exposures – then these could be signs of COVID-19 infection.
Fever and cough are the most common COVID-19 symptoms in children, according to the CDC. "The symptoms of COVID-19 are similar in adults and children and can look like other common illnesses, like colds, strep throat, or allergies," the CDC reports. In addition to the COVID-19 symptoms listed above, children may also experience:
In some children, fever may be the only sign of COVID-19 infection.
Parents should especially watch for the following novel coronavirus symptoms in children:
Coronavirus symptoms can last weeks or months for some people, known as "long haulers". These people have, in theory, recovered from the worst impacts of COVID-19 and are no longer contagious. However, they still have symptoms. There seems to be no consistent reason for the symptoms to stay around so long.
This condition can effect anyone – old and young, otherwise healthy people and those battling other conditions. It has been seen in those who were hospitalized with COVID-19 and patients with very mild symptoms. However, it appears to be less common in children compared to adults. Additionally, it's less common for those who have breakthrough infections (vaccinated people) to get the virus vs. unvaccinated people.
COVID-19 infection can cause inflammation and damage to the heart muscle and inflammation to the covering of the heart. According to the CDC, this heart damage can explain why some people have reported long-term symptoms like:
Those infected with COVID-19 can also experience lasting lung problems. Prolonged illness and continued symptoms can occur even in young adults without chronic medical conditions. This could lead to an extended absence from work, studies, or other activities. Researchers are still investigating what other short- and long-term health effects are associated with COVID-19.
If you have serious symptoms of illness, contact your primary care provider. UC Davis Health patients can use the MyUCDavisHealth symptom tracker to evaluate whether to seek help. Telehealth video visits and Express Care are also available.
If you think you've been exposed to COVID-19, please see current testing information.
If you have a medical emergency, call 911 and notify them of your COVID-19 symptoms.
To help limit spread of COVID-19, we have policies for visits to our hospital and outpatient clinics.