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5 Viruses That Can Cause Complications Later

Posted May 08, 2023 by Nikole M. Scalera, M.D.

Doctors looking at viruses

Viruses are a natural part of our daily lives. Fortunately, most viral infections clear after a few days to weeks when the body’s immune system launches an attack against them. However, some viruses, known as latent viruses, can remain in the body silently after the initial infection for prolonged periods without causing any symptoms and reactivate later on.

Latency is a survival strategy some viruses use to stay alive and spread. Latent viruses remain in the body and enter a latent phase, where the virus is inactive and does not actively replicate. Then, later on — many years, in some cases — the virus can come out of hiding and undergo a reactivation phase, where it begins to replicate and infect cells causing a repeat infection.

The reactivation phase can be triggered by internal or external factors, such as other viral infections, trauma, stress or a weakened immune system. The secondary infection can range from mild with minimal symptoms to lifelong problems.

Summa Health sheds light on 5 latent viruses and their common triggers for reactivation. Leading a healthy lifestyle and getting a vaccine, when applicable, is your best defense in avoiding pain later on.

Herpes Simplex Virus (HSV)

The herpes simplex virus family, including type 1 that can cause oral herpes (fever blisters and cold sores) and type 2 that can cause genital herpes, are latent viruses. During a herpes infection, a person’s skin can become painful, itchy or burn and then blisters appear. The blisters can break and become open sores that heal over one to two weeks. Once healed, the virus hides in the nerve cells under the surface of the skin only to reactivate later on.

Once a person is infected with the herpes virus, that person will have the infection the rest of their life. The sores can come back at any time. A variety of triggers can cause reactivation, such as stress, another illness, menstruation, and irritated skin or sunburn.

Varicella Zoster Virus

The varicella zoster virus causes chickenpox and then remains latent in the host’s nerve cells for many years. Eventually, it can reactivate as shingles. The skin becomes painful and then the shingles rash develops as a stripe of fluid-filled blisters that wraps around one side of the torso. The rash typically clears in seven to 10 days.

Shingles is more common in older adults, especially after age 50, and in people with chronic stress or who have weakened immune systems.

A vaccine is available to reduce a person’s risk for reinfection or if infected, decrease the severity and risk of complications from shingles. The U.S. Centers for Disease Control and Prevention recommends people over the age of 50 receive two doses of Shingrix, with two to six months between doses.

Epstein-Barr Virus (EBV)

As one of the most common human viruses, many people become infected with EBV during childhood, but typically experience very mild symptoms or even none at all. However, some infections do lead to mononucleosis, better known as mono, causing fever, body aches, sore throat and extreme fatigue. Most kids recover in two to four weeks.

Once people are infected with EBV, they carry the virus — usually in a dormant state — for the rest of their lives. Stress and a compromised immune system can trigger reactivation, but typically it causes no symptoms. However, in rare cases, reactivation can lead to infection once again in people with weakened immune systems.

Cytomegalovirus (CMV)

CMV is another very common infection that affects people of all ages, but typically does not cause any symptoms in healthy people. However, in people with weakened immune systems, especially those undergoing cancer treatment or an organ transplant, it can be very dangerous, even fatal. It can cause serious complications, including brain and liver inflammation, vision loss, pneumonia and more. 

Once a person is infected with CMV, they have it for life. In healthy people, CMV mainly stays dormant. The most common cause of a CMV reactivation is a weakened immune system.


The human immunodeficiency virus, better known as HIV, is a virus that attacks white blood cells that help the body fight infection, making a person more vulnerable to other infections. If left untreated, it can lead to AIDS (acquired immunodeficiency syndrome), the most severe stage of an HIV infection.

Most people with HIV develop flu-like symptoms, which can last for a few days to several weeks. The only way to know if a person has HIV is to get tested, since the symptoms are similar to many other illnesses.

HIV is a latent virus so once someone is infected, they have HIV for life. The virus infects immune fighting cells and can be found residing in lymph nodes.  Many people have mild symptoms and the diagnosis may be missed without proper testing.  HIV can be successfully treated and controlled with medication, but a universal cure does not exist yet. 

Learn more about Summa Health’s Infectious Disease Care by visiting


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