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COVID-19 is the illness that’s caused by the novel coronavirus, SARS-CoV-2. It can cause a variety of symptoms, such as fever, cough, and loss of smell and taste.

Some people who develop COVID-19 experience a mild illness with few symptoms while others can become seriously ill. While you’ve likely heard a lot about the more severe symptoms, you may be wondering what mild or moderate COVID-19 is like.

In this article, we’ll take a deeper dive into what we know so far about mild or moderate COVID-19, what the symptoms can be like, and when to see a doctor.

Commonly reported symptoms of COVID-19 are:

In what order do symptoms typically appear?

Symptom order can vary from one person to the next, but you may be curious about which COVID-19 symptoms are most likely to appear first.

An August 2020 study used mathematical modeling to predict the likely order of certain COVID-19 symptoms. Data from 55,924 people with confirmed COVID-19 was used for the study.

The symptoms investigated included fever, cough, and digestive symptoms. The researchers found that the predicted order of symptoms was:

  1. fever
  2. cough
  3. nausea or vomiting
  4. diarrhea

A separate dataset of 1,099 people with confirmed COVID-19 was then used in the model. This group was divided into two categories — severe and non-severe illness.

The predicted symptom order was the same for this smaller dataset as it was in the first dataset for 55,924 people. It was also the same between individuals with severe and non-severe illness.

COVID-19 severity is often divided into categories like mild, moderate, and severe. But what do these terms actually mean?

According to the COVID-19 treatment guidelines published by the National Institutes of Health (NIH), they’re defined as:

  • Mild illness. A person has any of the symptoms of COVID-19 except for shortness of breath and difficulty breathing.
  • Moderate illness. A person may have lower respiratory illness, such as pneumonia. However, their blood oxygen levels remain at 94 percent or higher.
  • Severe illness. A person has blood oxygen levels that are less than 94 percent, a high breathing rate, and signs of severe lung disease.

Research has found that about 81 percent of people with COVID-19 have a mild or moderate illness. According to the Centers for Disease Control and Prevention (CDC), most people with mild to moderate COVID-19 can recover at home.

Even if you have mild or moderate COVID-19, it’s still important to continue to monitor your symptoms as you recover. Even if you only have mild symptoms, it’s possible that they may begin to worsen, leading to more serious illness.

About asymptomatic infections

You may have heard that you can contract the new coronavirus and not have any symptoms at all. This is referred to as an asymptomatic infection.

Because people without COVID-19 symptoms aren’t always tested, it’s unknown how common asymptomatic infections actually are. One September 2020 review of 79 studies estimates that about 20 percent of people who contract SARS-CoV-2 never become sick.

Many people who are asymptomatic don’t know that they’ve contracted the virus. However, it’s still possible to spread the virus to others, which is why it’s so important to continue to take preventative measures like:

One potential symptom of COVID-19 is loss of smell or taste. An August 2020 review of 24 studies estimated a prevalence of 41 percent and 38.2 percent for loss of smell and taste, respectively.

Loss of smell and taste is also associated with mild COVID-19. A January 2021 study evaluated this symptom in 1,363 people with COVID-19.

Researchers observed loss of smell and taste in 85.9 percent of people with mild illness compared to 4.5 to 6.9 percent of people with moderate to severe illness. This symptom disappeared in 95 percent of individuals within 6 months.

“I felt a little congested, but nothing more than allergies could cause. Then I realized one afternoon I could no longer smell my coffee, so I got tested. The rapid test came back positive.”

— Jay, 39

The CDC notes that loss of smell and taste is more common in women and younger to middle-aged individuals.

Loss of smell and taste due to COVID-19 can happen without having a runny or stuffy nose. Additionally, data from an August 2020 review suggest that this symptom may appear prior to other symptoms of COVID-19.

Fever is one of the most commonly reported symptoms of COVID-19. However, it’s also possible to have COVID-19 and not have a fever.

For example, a May 2020 study evaluated the symptoms of mild COVID-19 in 172 people. It found that fever was only observed in 20 people (11.6 percent).

A July 2020 study assessed 147 encounters with people who had needed emergency medical services for COVID-19. It found that symptoms like fever and cough weren’t present during 43 of these encounters (almost 30 percent).

Additionally, the CDC notes that older adults often have a lower normal body temperature than younger individuals. Because of this, fever temperatures may also be lower, making it more difficult to recognize a fever in this age group.

“I never developed a fever or cough. My symptoms started with pain in the roof of my mouth, postnasal drip, and sneezing that lasted a day. Then my sense of smell began to rapidly decline until I couldn’t even smell dirty diapers. My smell returned after about 7 days.”

— Megan, 37

Like fever, a cough is also a commonly reported symptom of COVID-19. According to an early joint report from the World Health Organization (WHO) and Chinese officials, a dry cough is more common. However, a wet cough can also occur.

It’s also possible to have COVID-19 and not have a cough.

The May 2020 study on mild COVID-19 that we discussed above found that a cough was the most common symptom. However, it was still only observed in 69 out of 172 people (40.1 percent).

If you develop COVID-19 symptoms, it’s possible that your illness can transition from mild or moderate to severe. This typically happens about a week after your symptoms first appear but can happen earlier or later.

According to the CDC’s analysis of COVID-19 progression, the timeframe from symptom onset to breathing difficulties is typically between 5 to 8 days

In people who become severely ill, the length of time between the onset of their symptoms and admission to a hospital intensive care unit (ICU) is between 9.5 and 12 days.

How long it will take to recover from severe COVID-19 is unknown and can vary from person to person. Outcomes and recovery can be dependent on many factors, including age and the presence of other underlying health conditions.

How long does mild or moderate COVID-19 usually last?

Much of the research into COVID-19 has focused on severe illness. Because of this, there’s less information about exactly how long mild to moderate COVID-19 lasts.

A small July 2020 study focused on individuals who had mild to moderate COVID-19. It found that people with a mild or moderate illness had at least one symptom for an average of 9.82 days.

What’s long-haul COVID-19?

Some people who’ve had COVID-19, regardless of severity, can experience persistent symptoms for weeks or months after the acute illness passes. This is known as long-haul COVID-19.

Some examples of long-haul COVID-19 symptoms include:

We still know very little about how and why long-haul COVID symptoms appear. Doctors and scientists are currently working to learn more about this.

According to the CDC, anyone who has any of the symptoms of COVID-19 should get tested, even if the symptoms are very mild.

Other situations where testing is recommended include:

  • Close contact. It’s important to get tested if you’ve been in close contact with someone that has confirmed COVID-19. This means you’ve been within 6 feet of them for 15 minutes or longer over a 24-hour period.
  • High-risk activities. Some activities can put you at a higher risk of contracting SARS-CoV-2 and becoming ill with COVID-19, so it’s important to get tested after doing things like traveling or being at a large gathering.
  • Testing referral. It’s possible that your healthcare provider may ask you to get tested, such as prior to a surgery or procedure.

After you’ve gotten your test, you need to isolate at home until you receive your results. The reason for this is because if you do have the virus, you can potentially spread it to others while you’re waiting for your results.

The exact amount of time that you’re contagious is an area of ongoing research.

A November 2020 review examined viral shedding (spread) in 79 different studies of SARS-CoV-2. Researchers found that:

  • The amount of virus detected in the upper respiratory tract (nose and throat) peaked early on, generally in the first 3 to 5 days of illness.
  • In some studies, live virus was easily isolated from respiratory samples early on, but this was no longer the case by day 8 or 9 of illness.
  • People with more severe illness seem to shed virus for a longer time. However, some studies found no difference between mild or moderate and severe illness.
  • Individuals over the age of 60 appear to shed the virus longer than younger individuals.

Additionally, researchers had trouble isolating live virus by day 9 of illness. This lines up well with current CDC guidelines to isolate at home for 10 days if you have or suspect that you have COVID-19.

Taken together, it currently appears as if the virus is most contagious shortly after symptoms begin. However, some individuals may shed the virus for longer periods of time.

If you have COVID-19, when can you be around other people again?

The CDC has guidelines for when you can be around others again. You must meet all three of the following criteria before you can do so:

  1. It must be at least 10 days since your symptoms first appeared.
  2. You must have gone 24 hours without a fever and without using fever reducing medications like acetaminophen (Tylenol) and ibuprofen (Motrin, Advil).
  3. Your other symptoms of COVID-19 must be improving. The exception to this is loss of smell and taste, which can last for weeks or months after recovery.

If you tested positive without having symptoms, you can be around others if it’s been 10 days since your positive test.

COVID-19 can progress to a serious illness in some people. According to the CDC, some of the warning signs of serious illness to look out for include:

If you or someone else develops these symptoms, call 911 or your local emergency services immediately. Be sure to let the emergency dispatcher know that you’re seeking medical attention for someone that has or may have COVID-19.

Should you buy an at-home pulse oximeter?

A pulse oximeter is a small device that measures the amount of oxygen in your blood. It’s typically placed on your finger.

According to the American Lung Association, normal levels of oxygen saturation are between 95 to 97 percent. Levels below this can be a sign that your respiratory system is having a hard time supplying oxygen to the organs and tissues in your body.

An at-home pulse oximetry reader can help you monitor your blood oxygen levels when you have COVID-19, particularly if you’re at risk of severe illness. Talk to your doctor before purchasing a pulse oximeter for this purpose.

It’s also important to remember not to focus just on pulse oximetry readings alone. Listen to what your body is telling you and also carefully monitor other symptoms like cough, shortness of breath, and chest pain.

COVID-19 symptoms can vary widely from person to person. It’s even possible to have COVID-19 without some of the commonly reported symptoms like a fever and cough.

Most people with COVID-19 have a mild or moderate illness. People with mild illness usually have COVID-19 symptoms but no shortness of breath or trouble breathing. Moderate illness is associated with conditions like pneumonia; however, blood oxygen levels are generally normal.

It’s important to get tested if you have any symptoms of COVID-19, regardless of how mild they may be, and to isolate at home until you get your results. This can prevent you from inadvertently spreading the virus to others who could develop a more severe case of the disease.

People with mild or moderate COVID-19 can often recover at home, but need to continue to monitor their symptoms in case they worsen.