It’s one of those things you might hear on a commercial: If you’ve had chickenpox, you’re at risk for shingles. But why? Why does an infection from your childhood come back as you get older? Why does the virus stay in your body and how does it morph into something totally different? Turns out that some viruses can become dormant, also known as virus latency. They stay with you forever.
If you’re like me, the thought of viruses staying in my body only to wake up and attack later is terrifying. And with COVID and monkeypox taking center stage in our lives right now, I can’t help but worry and wonder: What does this mean for new viruses spreading across the globe?
Virus Latency Explained
Viruses have different ways of surviving within a host. (That’s who we are: Hosts.)
Infectious disease provider Patrick Jackson, MD, explains that some viruses:
- Show up and then leave, pushed out by the immune system
- Stay in the body, actively reproducing, without causing symptoms
- Live and reproduce in a part of the body where the immune system is too weak to force it out
- Go into a dormant state in the body, under the immune system’s radar
The Virus That Comes & Goes
Most stick around until the immune system completely clears them out. This can take a few days or weeks.
We know you can get reinfected by a virus if exposed, because the original virus is no longer present within the body. You can get influenza, or the flu, and the common cold, for example, over and over.
The Virus That Stays Invisible
Some viruses can cause persistent infection without symptoms. “For example, hepatitis C virus can grow continuously in the body for decades before symptoms of liver damage develop,” Jackson says. “This isn’t latency, because virus keeps being produced, but a person could very well not know they’re infected.”
The Virus That Hides Out
Other viruses can cause persistent infection within a particular body part. For example, the Ebola virus will locate itself in the brain, eyes, and testes, where the immune system has a harder time clearing infected cells.
The Dormant Virus
But other viruses can become latent.
After the initial infection, the virus becomes inactive or dormant within your cells. You don’t notice it, but the genetic information stays after recovery. Then the making of a new virus is lying within you.
This evolutionary strategy allows some viruses to wait for better circumstances to transmit themselves. They stay camouflaged from the immune system, in hiding. They can go years without being detected or eliminated.
Then, when the conditions for their survival improve, they activate.
Common Dormant Viruses
If you were born before 1995, then you're likely familiar with chickenpox and oatmeal baths as a kid. The varicella-zoster virus (chickenpox) can cause shingles later in life.
Thankfully there’s a vaccine for those over 50 years old.
Other common viruses that can stay dormant:
- Herpes simplex 1 and 2 (oral and genital herpes)
- Epstein-Barr virus (mononucleosis)
- Cytomegalovirus (a major cause of transplant-related complications)
A Special Case: Epstein-Barr virus
A dormant virus typically isn’t associated with so many different conditions, making this one a special case.
Vaccines & Risk in Future Generations
Thanks to the chickenpox vaccine, the Gen Z population has a chance to avoid the struggles of chickenpox and shingles altogether. “It’s true that if you have never been exposed to the chickenpox virus, then you can’t get shingles,” Jackson shares.
However, the risk isn’t zero. Vaccinated people can get shingles from breakthrough infections of chickenpox or from the chickenpox vaccine, as it contains a live virus. This happens less frequently, though. And when it does, the symptoms tend to be milder than those caused by the virus. The shingles vaccine isn’t a live virus.
Triggers That Reactivate
If you're over 50 or under with a weakened immune system, you should get two doses of the vaccine, Shingrix.
When the conditions are right, an infected cell is triggered to start making a new virus that can infect the host. Jackson explains this process is similar among plants and the lodgepole pine tree. The seeds only release and germinate after a forest fire — waiting for the perfect time to succeed.
Viruses wake up to different types of triggers. For example:
- Herpes can get triggered by sun exposure, dental surgery, or psychological stress
- HIV reacts after another viral infection
“Reactivation is a key area of research in HIV. If you could reactivate cells that were latently infected with HIV, you could potentially kill those cells off and achieve a durable cure. This is the so-called “kick-and-kill” strategy,” Jackson explains.
Unfortunately, we don’t yet know how to reactivate every latently infected cell. For shingles, it could be the risk increases as we age, and our immune system is compromised with different conditions and medications.
It’s not rare that a young person under 50 may have shingles flare up. Typically, this person will be tested for HIV, as shingles reactivation can be one manifestation of the disease. But shingles can be random, even in a younger person without any immune system issues.
COVID-19 & Monkeypox
“While COVID-19 is a new virus, it is closely related to seasonal viruses that are one cause of the common cold,” says Jackson. This virus causes a brief, acute infection in people with normal immune systems. Latency isn’t expected to happen.
Monkeypox hasn’t been well studied but is closely related to smallpox. Since smallpox can’t become dormant, it’s one of the few pathogens to be globally eradicated.
For now, it seems we don’t have to worry about COVID-19 or monkeypox causing issues down the road. But it’s important to stay up to date on vaccines to avoid viruses that can become latent or reactive later in life.