What It Means to Be Asymptomatic

When you are ill—and, in some cases, contagious—but you feel fine

Asymptomatic means the absence of symptoms. If your provider tells you that you are asymptomatic, it means you have a disease or condition but do not have any symptoms or observable signs that you are sick.

The term asymptomatic is often used to describe cases of illness that are symptom-free for all or part of the time. However, the term pre-symptomatic is sometimes used to differentiate those cases that start with no symptoms but then go on to develop them.

This article goes over the meaning of asymptomatic and why it can be a concern to both your health and the health of others. You will learn about types of asymptomatic infections and diseases, how they are diagnosed, and how they are treated.

Understanding Asymptomatic Illnesses

Laura Porter / Verywell

When You Might Be Asymptomatic

It may seem odd that you can be unwell and not know it, but there are a variety of instances in which this can occur.

You may be asymptomatic when:

  • Your immune system is successfully fighting off an invader before you can recognize that it is there (e.g., the flu virus or the bacterium that causes strep throat)
  • You are in recovery or remission from an illness in which you experienced symptoms (e.g., a sinus infection)
  • You are sick with something that typically only shows symptoms in more advanced stages (e.g., chlamydia or colon cancer)
  • You have a condition that slowly develops (e.g, high blood pressure or diabetes)
  • You have a chronic illness that goes through recurring cycles of being asymptomatic and then having a return of symptoms. (e.g., multiple sclerosis can follow a relapsing-remitting pattern)

In some cases, screening tests can detect an issue in people even if they are asymptomatic. However, if you don't feel sick, you're less likely to seek care.

Concerns With Being Asymptomatic

Being symptom-free can be a good thing for obvious reasons. But it can also delay diagnosis and treatment.

And since you're unlikely to change habits like going to work if you feel fine, you can unknowingly pass along infectious conditions to others.

Personal Health Risks

Being asymptomatic is concerning because it means you won't get treatment you need at a time when a disease or condition may be most treatable and least likely to cause complications.

For example, if you have high blood pressure, but no symptoms, you still need treatment to avoid potential issues such as vision problems, kidney damage, and a heart attack.

If you have lung cancer, it may take years for you to experience symptoms. You may be asymptomatic even though the cancer is growing and spreading.

The disease may not be detected until its later stages (which is usually the case). It's most treatable, however, in stage 1.

How Do I Know If I'm Asymptomatic?

There are different tests providers can use to find out if a person has an asymptomatic disease. A person might need to be tested if they're at risk for exposure or just as part of routine healthcare.

For example, most cancer screening tests are designed to find cancer when it is still in the asymptomatic phase. With a lot of cancers, the earlier it's diagnosed and treated the better.

General health screenings, such as checking blood pressure and blood sugar (glucose) levels, can spot chronic conditions like hypertension and diabetes before they cause symptoms.

Again, the sooner they are treated the better in terms of preventing complications.

An asymptomatic finding can also be a sign that a person has a subclinical infection, which means they have a disease but do not feel sick.

For example, some people may have a positive test for strep throat, genital herpes, HIV, or hepatitis but do not have any symptoms. It's still important for them to know that they are sick even if they feel fine so they can take steps to prevent spreading the illness to others.

Treating a disease that has not yet shown any symptoms can make a difference in your long-term health or even survival. For example, controlling hypertension or diabetes can add years to your life, and removing polyps found during a screening colonoscopy can prevent the development of colon cancer.

Can You Have COVID-19 Without Symptoms?

Yes. And though you may not feel sick, you can still spread the virus to others. If COVID-19 symptoms do appear, they usually show up between two and 14 days after exposure. If you've been exposed to someone who is infected, get tested whether you are symptomatic or not.

What Does It Mean If I'm Asymptomatic?

Having an asymptomatic condition could refer to many different situations. It's also hard to know whether an asymptomatic condition will eventually cause symptoms or not.

If you learn that you have an asymptomatic condition, you may need to make healthcare decisions to try to improve your long-term quality of life or survival.

On the other hand, an asymptomatic finding doesn't always mean you should, or can, do anything to change the situation. In some cases, the early detection of a condition will not lead to an improved quality of life or greater survival. In this case, additional testing and medical interventions would not be helpful—in fact, they could be harmful.

Not only is it emotionally upsetting and stressful, but the unnecessary medical work-up itself could pose risks (e.g., the surgical risk from a biopsy) and can be costly.

Are Asymptomatic Diseases Overdiagnosed?

Overdiagnosis of conditions can lead to overtreatment. That's one reason there is controversy in the medical community about using screening tests, even those for cancer.

While we know that colon cancer screening and lung cancer screening save lives, it's not clear that other tests—like prostate screening or breast cancer screening—improve survival for people with those cancers, especially when you weigh the benefits and risks.

These screening tests can increase the diagnosis of cancer and lead to earlier treatment, but they can also contribute to overdiagnosis. One example is prostate-specific antigen (PSA) screening, a test that may result in unnecessary evaluations and harmful treatment for some while improving survival for others.

After You've Tested

There are situations where treating an asymptomatic condition does make a difference.

For example, if a partner lets you know that they have a sexually transmitted infection (STI), you can get tested even if you don't have symptoms. If you also have the infection, getting tested will help ensure that you get treated and take steps to prevent spreading it to others.

If you have an asymptomatic condition, your provider will consider your situation very carefully before recommending the next steps for you to take. You should also feel empowered to ask them questions about what being asymptomatic means for you.

Questions to Ask Your Healthcare Provider

  • What are the chances that I will develop the disease for which I'm now asymptomatic? How might that change with treatment?
  • What might treatment entail? What are the pros and cons?
  • What are the chances that nothing would happen if did nothing about the finding? (Sometimes looking at statistics is helpful.)
  • Is there concern that this condition is overdiagnosed?
  • What would you do if you were in my shoes?

Ultimately, your decision will be based on the illness you have, what it means for your health, what treatments are available, and the risks involved.


If you are sick but do not have symptoms, it means you're asymptomatic. While you might feel free to go about your regular day-to-day activities since you aren't feeling sick, it's important to know that you still might be able to spread the illness to others even if you don't have symptoms.

Sometimes, an asymptomatic disease is picked up by a screening test. That said, asymptomatic conditions can go unchecked because people are less likely to seek care if they aren't feeling sick.

If your provider tells you that you have an asymptomatic disease or infection, ask them what steps you need to take to protect yourself and others.

Frequently Asked Questions

  • How do I know if I am asymptomatic?

    If you don't have symptoms of an illness or disease but you know you were exposed to it, you might be able to find out if you have it by getting a test.

    For example, if a partner informs you that they have an STI, you may get tested and find out that you also have it even though you didn't have any symptoms.

  • What percentage of people who test positive for COVID remain asymptomatic?

    It's estimated that as much as 60% of people who test positive for COVID-19 do not have symptoms.

  • How long do you have to isolate if you have asymptomatic COVID?

    According to the Centers for Disease Control and Prevention (CDC), you need to self-isolate for five days if you have asymptomatic COVID. Once those five days are up, you should still wear a mask around other people for another five days.

  • Can you have the flu and be asymptomatic?

    The flu can be asymptomatic. However, you can still spread the virus to other people even if you don't feel sick. In fact, research has shown that flu cases around the world are often the result of asymptomatic transmission.

  • Can cancer be asymptomatic?

    In the early stages of cancer, a person may not have symptoms. When a person with cancer is asymptomatic they may only find out they have cancer because it showed up on a screening test.

12 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. World Health Organization. Coronavirus disease (COVID-19): How is it transmitted?

  2. Memorial Sloan Kettering Cancer Center. Stages of Non-Small Cell and Small Cell Lung Cancer.

  3. Centers for Disease Control and Prevention (CDC). Symptoms of COVID-19.

  4. Centers for Disease Control and Prevention (CDC). Overview of Testing for SARS-CoV-2, the virus that causes COVID-19.

  5. Aberle DR, Adams AM, Berg CD, et al. Reduced lung-cancer mortality with low-dose computed tomographic screening. N Engl J Med. 2011;365(5):395-409.  doi:10.1056/NEJMoa1102873

  6. Nielsen C. Six screening tests for adults: What's recommended? What's controversial?. Cleve Clin J Med. 2014;81(11):652-5.  doi:10.3949/ccjm.81gr.14003

  7. Martin RM, Donovan JL, Turner EL, et al. Effect of a Low-Intensity PSA-Based Screening Intervention on Prostate Cancer Mortality: The CAP Randomized Clinical Trial. JAMA. 2018;319(9):883-895.  doi:10.1001/jama.2018.0154

  8. Ohio State University Wexner Medical Center. STIs you can have with no symptoms.

  9. Johansson MA, Quandelacy TM, Kada S, et al. SARS-CoV-2 Transmission From People Without COVID-19 SymptomsJAMA Network Open. 2021;4(1):e2035057. doi:10.1001/jamanetworkopen.2020.35057

  10. Centers for Disease Control and Prevention (CDC). CDC Updates and Shortens Recommended Isolation and Quarantine Period for General Population.

  11. Cohen C, Kleynhans J, Moyes J, et al. Asymptomatic transmission and high community burden of seasonal influenza in an urban and a rural community in South Africa, 2017–18 (PHIRST): a population cohort studyThe Lancet Global Health. 2021;9(6):e863-e874. doi:10.1016/s2214-109x(21)00141-8

  12. Cornell Research. Do I Have Hidden Cancer?.

Additional Reading