Table of ContentsView AllTable of ContentsWhat Are White Blood Cells?Low WBC Count and COVID-19SymptomsDiagnosis and TreatmentPrevention
Table of ContentsView All
View All
Table of Contents
What Are White Blood Cells?
Low WBC Count and COVID-19
Symptoms
Diagnosis and Treatment
Prevention
Having a lowwhite blood cell(WBC) count, also known asleukopenia, means that your body is not making enough of the immune cells it needs to fight invaders (pathogens) like bacteria and viruses. A low WBC count puts you at risk of infections, including coronavirus (COVID-19) infections. Research has found that having fewer lymphocytes, a type of white blood cell, can be a risk factor for severe cases of COVID.
Verywell / Jessica Olah
White blood cells are a type of immune cell. They are created in thebone marrow, the spongy part of your bones, and can be found in blood and in tissues that support the immune system, which are known as lymph tissues. There are several types of white blood cells, and each plays a role in fighting infection and disease in the body:
Your WBC count is measured with a blood test called acomplete blood count(CBC). The results are reported as WBCs per microliter (µL). A low WBC count signals a problem with your immune system. This is a common problem in people living with cancer or taking medications that suppress the immune system.
The table below shows the normal ranges of WBC counts. Anything below these ranges is considered low.
An Overview of White Blood Cell Disorders
The Connection Between White Blood Cell Count and COVID-19
A high WBC count, also called leukocytosis, is usually a sign that the body is fighting an infection, and the same is true in COVID-19. Research has shown that people who test positive for COVID-19 but have no symptoms typically have a high WBC count, particularly lymphocytes.
Studies have shown more severe illness and death in people with COVID-19 who had a high WBC count at hospital admission.But a number of other studies have found that lower WBC counts or elevated WBC counts with decreased levels of lymphocytes in particular were also associated with more severe illness and death in COVID-19.
This can be because the levels of some types of WBCs like neutrophils are higher as the body fights off the virus, while levels of lymphocytes remain low.
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Symptoms of COVID-19
COVID-19 symptoms can include:
A low white blood cell count doesn’t cause any symptoms on its own, but people who have a low WBC count can develop various symptoms due to infections that their bodies are not able to fight off. People with the following conditions typically have low WBC counts:
More specifically, though, people who have low levels of lymphocytes have a condition called lymphocytopenia orlymphopenia. It occurs when your body doesn’t make enough of these blood cells. It can also be acquired, such as in people with AIDS.
Symptoms of diseases that can cause a low white blood cell count like HIV, cancer treatment, and uncontrolled diabetes can include:
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Diagnosis and Treatment of COVID-19
A diagnosis of COVID-19 is confirmed with two kinds of tests:
The Centers for Disease Control and Prevention (CDC) recommends that anyone with symptoms of COVID-19 take precautions to prevent spread and get tested if at risk for severe illness.
If you have symptoms of COVID-19, you will need to follow steps to protect the people around you. The CDC recommends staying home and away from others until your symptoms improve for 24 hours without taking fever-reducing medications. After that, you may resume normal activities but should take precautions, like wearing a mask and physically distancing, for the next five days.
Generally, hospitalized patients with COVID-19 are treated with remdesivir or dexamethasone or similar corticosteroids if they require supplemental oxygen.You may also be treated with blood thinners to control blood clotting.
People who are dealing with the virus at home should monitor their symptoms and stay in touch with their healthcare providers if they are concerned. The COVID-19 Treatment Guidelines Panel recommends the following antiviral treatments for nonhospitalized adults:
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You should head to the emergency department or call 911 if you have trouble breathing or your symptoms suddenly become worse.
Overall, you will want to:
Ways to Prevent COVID-19 or Infections
There may not be many ways to prevent having a low blood count. Typically, a low WBC count is the result of an infection or condition or a medication that you need.
You can, however, take steps to protect yourself against COVID-19, and you should be extra vigilant with these steps if you know you have a low WBC count. Usually, people with low WBC counts are educated on how to prevent infection, and much of that guidance mirrors the strategies to avoid COVID-19, such as:
You should also stay up-to-date withCOVID-19 vaccines. Recent spikes in infection have proven the effectiveness of the vaccine, with far more unvaccinated people being hospitalized with the virus than vaccinated people.
Summary
Having a low white blood cell count means you are at higher risk of infections because WBCs help fight pathogens in your body. You can have a low WBC count due to a condition or infection or medications you are taking. Recent research has shown that people with a low WBC count are more likely to have a severe case of COVID-19. You should practice prevention strategies against COVID-19 vigilantly if you have a low WBC count.
The information in this article is current as of the date listed, which means newer information may be available when you read this. For the most recent updates on COVID-19, visit ourcoronavirus news page.
18 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.National Cancer Institute.White blood cell.Leukemia & Lymphoma Society.Understanding blood counts.Han H, Xu Z, Cheng X, et al.Descriptive, retrospective study of the clinical characteristics of asymptomatic COVID-19 patients.mSphere. 2020;5(5). doi:10.1128/mSphere.00922-20National Human Genome Research Institute.Lymphocytes.Zhu B, Feng X, Jiang C, et al.Correlation between white blood cell count at admission and mortality in COVID-19 patients: a retrospective study.BMC Infect Dis. 2021;21(1):574. doi:10.1186/s12879-021-06277-3Zhang X, Tan Y, Ling Y, et al.Viral and host factors related to the clinical outcome of COVID-19.Nature. 2020;583(7816):437-440. doi:10.1038/s41586-020-2355-0Yang L, Jin J, Luo W, Gan Y, Chen B, Li W.Risk factors for predicting mortality of COVID-19 patients: A systematic review and meta-analysis.PLoS One. 2020;15(11):e0243124. doi:10.1371/journal.pone.0243124Centers for Disease Control and Prevention.Symptoms of COVID 19.National Institutes of Health.What is lymphocytopenia?Aplastic Anemia and MDS International Foundation.What are the symptoms of low blood counts?.Food and Drug Administration.COVID-19 test basics.Centers for Disease Control and Prevention.If you are sick or caring for someone.Centers for Disease Control and Prevention.Preventing spread of respiratory viruses when you’re sick.National Institutes of Health.Coronavirus disease 2019 (COVID-19) treatment guidelines.Food and Drug Administration.Actemra label.National Institutes of Health.Therapeutic management of adults hospitalized with COVID-19.Centers for Disease Control and Prevention.How to protect yourself and others.Moline HL, Whitaker M, Deng L, et al.Effectiveness of COVID-19 vaccines in preventing hospitalization among adults aged ≥65 years - COVID-NET, 13 states, February-April 2021.MMWR Morb Mortal Wkly Rep. 2021;70(32):1088-1093. doi:10.15585/mmwr.mm7032e3
18 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.National Cancer Institute.White blood cell.Leukemia & Lymphoma Society.Understanding blood counts.Han H, Xu Z, Cheng X, et al.Descriptive, retrospective study of the clinical characteristics of asymptomatic COVID-19 patients.mSphere. 2020;5(5). doi:10.1128/mSphere.00922-20National Human Genome Research Institute.Lymphocytes.Zhu B, Feng X, Jiang C, et al.Correlation between white blood cell count at admission and mortality in COVID-19 patients: a retrospective study.BMC Infect Dis. 2021;21(1):574. doi:10.1186/s12879-021-06277-3Zhang X, Tan Y, Ling Y, et al.Viral and host factors related to the clinical outcome of COVID-19.Nature. 2020;583(7816):437-440. doi:10.1038/s41586-020-2355-0Yang L, Jin J, Luo W, Gan Y, Chen B, Li W.Risk factors for predicting mortality of COVID-19 patients: A systematic review and meta-analysis.PLoS One. 2020;15(11):e0243124. doi:10.1371/journal.pone.0243124Centers for Disease Control and Prevention.Symptoms of COVID 19.National Institutes of Health.What is lymphocytopenia?Aplastic Anemia and MDS International Foundation.What are the symptoms of low blood counts?.Food and Drug Administration.COVID-19 test basics.Centers for Disease Control and Prevention.If you are sick or caring for someone.Centers for Disease Control and Prevention.Preventing spread of respiratory viruses when you’re sick.National Institutes of Health.Coronavirus disease 2019 (COVID-19) treatment guidelines.Food and Drug Administration.Actemra label.National Institutes of Health.Therapeutic management of adults hospitalized with COVID-19.Centers for Disease Control and Prevention.How to protect yourself and others.Moline HL, Whitaker M, Deng L, et al.Effectiveness of COVID-19 vaccines in preventing hospitalization among adults aged ≥65 years - COVID-NET, 13 states, February-April 2021.MMWR Morb Mortal Wkly Rep. 2021;70(32):1088-1093. doi:10.15585/mmwr.mm7032e3
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
National Cancer Institute.White blood cell.Leukemia & Lymphoma Society.Understanding blood counts.Han H, Xu Z, Cheng X, et al.Descriptive, retrospective study of the clinical characteristics of asymptomatic COVID-19 patients.mSphere. 2020;5(5). doi:10.1128/mSphere.00922-20National Human Genome Research Institute.Lymphocytes.Zhu B, Feng X, Jiang C, et al.Correlation between white blood cell count at admission and mortality in COVID-19 patients: a retrospective study.BMC Infect Dis. 2021;21(1):574. doi:10.1186/s12879-021-06277-3Zhang X, Tan Y, Ling Y, et al.Viral and host factors related to the clinical outcome of COVID-19.Nature. 2020;583(7816):437-440. doi:10.1038/s41586-020-2355-0Yang L, Jin J, Luo W, Gan Y, Chen B, Li W.Risk factors for predicting mortality of COVID-19 patients: A systematic review and meta-analysis.PLoS One. 2020;15(11):e0243124. doi:10.1371/journal.pone.0243124Centers for Disease Control and Prevention.Symptoms of COVID 19.National Institutes of Health.What is lymphocytopenia?Aplastic Anemia and MDS International Foundation.What are the symptoms of low blood counts?.Food and Drug Administration.COVID-19 test basics.Centers for Disease Control and Prevention.If you are sick or caring for someone.Centers for Disease Control and Prevention.Preventing spread of respiratory viruses when you’re sick.National Institutes of Health.Coronavirus disease 2019 (COVID-19) treatment guidelines.Food and Drug Administration.Actemra label.National Institutes of Health.Therapeutic management of adults hospitalized with COVID-19.Centers for Disease Control and Prevention.How to protect yourself and others.Moline HL, Whitaker M, Deng L, et al.Effectiveness of COVID-19 vaccines in preventing hospitalization among adults aged ≥65 years - COVID-NET, 13 states, February-April 2021.MMWR Morb Mortal Wkly Rep. 2021;70(32):1088-1093. doi:10.15585/mmwr.mm7032e3
National Cancer Institute.White blood cell.
Leukemia & Lymphoma Society.Understanding blood counts.
Han H, Xu Z, Cheng X, et al.Descriptive, retrospective study of the clinical characteristics of asymptomatic COVID-19 patients.mSphere. 2020;5(5). doi:10.1128/mSphere.00922-20
National Human Genome Research Institute.Lymphocytes.
Zhu B, Feng X, Jiang C, et al.Correlation between white blood cell count at admission and mortality in COVID-19 patients: a retrospective study.BMC Infect Dis. 2021;21(1):574. doi:10.1186/s12879-021-06277-3
Zhang X, Tan Y, Ling Y, et al.Viral and host factors related to the clinical outcome of COVID-19.Nature. 2020;583(7816):437-440. doi:10.1038/s41586-020-2355-0
Yang L, Jin J, Luo W, Gan Y, Chen B, Li W.Risk factors for predicting mortality of COVID-19 patients: A systematic review and meta-analysis.PLoS One. 2020;15(11):e0243124. doi:10.1371/journal.pone.0243124
Centers for Disease Control and Prevention.Symptoms of COVID 19.
National Institutes of Health.What is lymphocytopenia?
Aplastic Anemia and MDS International Foundation.What are the symptoms of low blood counts?.
Food and Drug Administration.COVID-19 test basics.
Centers for Disease Control and Prevention.If you are sick or caring for someone.
Centers for Disease Control and Prevention.Preventing spread of respiratory viruses when you’re sick.
National Institutes of Health.Coronavirus disease 2019 (COVID-19) treatment guidelines.
Food and Drug Administration.Actemra label.
National Institutes of Health.Therapeutic management of adults hospitalized with COVID-19.
Centers for Disease Control and Prevention.How to protect yourself and others.
Moline HL, Whitaker M, Deng L, et al.Effectiveness of COVID-19 vaccines in preventing hospitalization among adults aged ≥65 years - COVID-NET, 13 states, February-April 2021.MMWR Morb Mortal Wkly Rep. 2021;70(32):1088-1093. doi:10.15585/mmwr.mm7032e3
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