This article discusses the link between a low white blood cell count and COVID. It also explains how white blood cells are affected by COVID.

What Are White Blood Cells?

White blood cells are a type of immune cell. They are created in the bone 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:

Granulocytes, including neutrophils, eosinophils, and basophils, are released during allergic reactions and asthma Monocytes help fight off infections and facilitate healing Lymphocytes, including T-cells and B cells, help control immune responses

Your WBC count is measured with a blood test called a complete 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.

Lymphocytes circulate throughout your body, and create antibodies, proteins released to fight pathogens, to help your immune system fight infections. B cells focus on attacking invading viruses and bacteria, while T-cells destroy the body’s own cells that have been damaged by things like viruses or cancer.

The high level of lymphocytes observed in asymptomatic people with COVID-19 makes sense. It means that their immune systems are doing a good job of keeping the coronavirus in check by creating antibodies and destroying damaged cells.

Studies have shown more severe illness and death in people with COVID-19 who had a high WBC count. A number of other studies have found that lower WBC counts or elevated WBC counts with decreased levels of lymphocytes in particular were 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.

Symptoms of COVID-19

The symptoms of COVID-19 and a low WBC count are quite different. COVID-19 symptoms can include:

Fever Chills Cough Shortness of breath Difficulty breathing Fatigue Muscle aches Headaches Loss of taste or smell Sore throat Congestion or runny nose Nausea or vomiting Diarrhea

There are no actual symptoms of a low white blood cell count, 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:

Autoimmune diseases, such as rheumatoid arthritisCancer treatment like radiationInfections like HIV and hepatitisAntipsychotic medicationsAgranulocytosis, which is when your body doesn’t make enough neutrophilsNeutropenia, which is when your body has a low level of neutrophils

More specifically, though, people who have low levels of lymphocytes have a condition called lymphocytopenia or lymphopenia. 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:

Frequent or repeat infectionsInfections that won’t resolveUnusual or rare infectionsFeversBladder infectionsMouth soresSkin infectionsSinus infections or stuffy nose

Diagnosis and Treatment of COVID-19

A diagnosis of COVID-19 is confirmed with two tests:

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A viral test indicates if you have a current infection. An antibody test can show if you had a past infection.

The Centers for Disease Control and Prevention (CDC) recommends that anyone with symptoms of COVID-19 or who has been directly exposed to someone who is positive for COVID be tested for the virus.

There is only one medication approved by the Food and Drug Administration to treat COVID-19 at the moment: Veklury (remdesivir). However, it is reserved for the treatment of hospitalized people over the age of 12. There are multiple other medications that have Emergency Use Authorization, such as Actemra (tocilizumab).

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 doctors if they are concerned. 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:

Use over-the-counter medications like Tylenol (acetaminophen) to manage fever and other symptoms. Drink plenty of fluids. Get rest. Wear a mask if you have to be around others. Wash your hands frequently. Avoid sharing utensils or personal items with others. Clean shared surfaces frequently.

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:

Wear a mask. Wash hands frequently. Avoid large crowds, especially indoors. Avoid people who are sick. Clean and disinfect the areas around you frequently.

Unlike with some other infections like HIV, you can also be vaccinated against COVID-19. 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 our coronavirus news page.

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