Medically reviewed by Alana Biggers, M.D., MPH — By Carolyn Farnsworth Medical News Today
Some studies suggest a link between COVID-19 vaccines and reactivation of the virus that causes shingles. While evidence suggests this could be possible, it is at the very least uncommon.
Shingles is a fairly common condition that may affect roughly 20–30% of people in their lifetime, with the risk of developing shingles increasing with ageTrusted Source. It occurs following the reactivationTrusted Source of the varicella-zoster virus (VZV). Usually, a person will only develop shingles once in their life, but shingles can reactivate several times in some people.
Several case reports note people experiencing a shingles flare-up after receiving a COVID-19 vaccine. While evidence cannot attribute the flares to the vaccine, it may be possible that the immune response to the vaccine might trigger a flare. Some studies suggest this may not be an adverse event and just a coincidence. However, more research is still necessary to investigate the association.
In this article, we will discuss the possible association between COVID-19 vaccines and the reactivation of VZV.
Is there a connection?
To help prevent the transmission of severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2), health experts advise that people receive a COVID-19 vaccine as soon as possible. While the Centers for Disease Control and Prevention (CDC) state that the vaccines are safe and effectiveTrusted Source, some people may experience side effectsTrusted Source.
Researchers continue to monitor the safetyTrusted Source of these vaccines and investigate any potential safety issues. Some evidence suggests that a shingles flare may be an adverse event after vaccination (AEAV)Trusted Source. However, a 2021 systematic reviewTrusted Source notes that there is currently no definitive link between the vaccine and shingles. Still, the article states it could be an uncommon but possible event. As such, more research is necessary.
A 2021 articleTrusted Source reports two cases of shingles eruptions in adults after vaccination with an mRNA COVID-19 vaccine. In both cases, the individuals previously had chickenpox, which also results from VZV, but not shingles. While the researchers note that these cases may be a coincidence, they also highlight the potential influence of stress and the immune response to the vaccine.
They note that following vaccination, some people may experience lymphocytopenia or lower levels of white blood cells. The researchers add that this temporary period of lymphocytopenia may be sufficient to trigger VZV reactivation and result in a shingles flare.
This is consistent with another 2021 articleTrusted Source that suggests that an immune reaction following vaccination may allow VZV to escape from its latent phase and cause a shingles eruption.
Furthermore, a 2021 paper on older adults and a 2021 case series on people with an autoimmune condition highlight cases of shingles following COVID-19 vaccination. While the studies cannot prove causality, they suggest that it could be a plausible but rare AEAV. While more research is necessary, these findings may indicate the requirement for further vigilance and safety monitoring, particularly for those at higher risk of shingles.
Other research also highlights the potential role that stress may play. Stressors from social restrictions, new variants, and the process of vaccination may contribute towards affecting the immune response.
However, current evidence cannot attribute a definitive link between the two, and the CDC still recommends COVID-19 vaccination for all people aged 5 and older. Even if there is an association, it is a rare side effect, and the benefits of vaccination outweigh the potential risks.
It is also worth noting that COVID-19 vaccines do not cause shingles, and a person will not directly acquire shingles from a COVID-19 vaccine. If the events are related, they will only occur in individuals with dormant VZV from a previous case of chickenpox or shingles.
Definitions
ShinglesTrusted Source is a viral infection that results from the reactivation of VZV, the same virus that causes chickenpox. After chickenpox, the virus remains dormant in the nerve cells. Following an unknown trigger, the virus reactivates and causes a second eruption, known as herpes zoster, or shingles.
Symptoms of shingles includeTrusted Source a burning or tingling sensation with an itchy and painful rash that resembles chickenpox. However, unlike in people with chickenpox, the rash appears in a cluster and usually affects one side of the body.
The term COVID-19Trusted Source refers to a disease caused by the SARS-CoV-2 virus. This is a type of coronavirus that may cause relatively mild symptoms that do not require specialist treatment. However, it may result in severe breathing problems that require hospitalization in some people. In other cases, it can be fatal.
People may experience a variety of symptoms of COVID-19, such as fever and coughing, that might appear 2–14 days after exposure to SARS-CoV-2. Some individuals may also develop health issuesTrusted Source that continue for weeks or months.
Due to the potential health risk of COVID-19, scientists were able to develop vaccinesTrusted Source to help protect people against COVID-19 by providing immunity to SARS-CoV-2. These vaccines contain harmless material from the virus that the immune system uses to help fight off infection. In the United States, currently available vaccines include the following:
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Causes of shingles
Shingles results from the reactivation of VZV. After recovery from chickenpox, the virus lays dormant in the sensory ganglia of the cranial nerve or the dorsal root ganglia within the peripheral nervous system. The virus can hide in the nervous system, where it can remain indefinitely in a dormant state.
Like waking up from hibernation, the virus can reactivate and travel down nerve fibers to cause a new active infection. At present, the trigger for reactivation is unknownTrusted Source. However, research suggests it may occur when something weakens the immune system, prompting the virus to reactivate.
When to contact a doctor
Anyone who believes that they have developed shingles should contact a doctor as soon as possible. A doctor will be able to diagnose shingles and provide appropriate treatment.
In many cases, a primary care physician can manage shingles care, but people may require specialist care in some cases. Getting treatment shortly after the onset of symptoms can help decrease the duration and severity of the infection. It can also help prevent potential complicationsTrusted Source of shingles, such as vision problems.
Treatment options
There are many treatment options available for shingles. Typically, a doctor may recommend antiviral medications, as they can help treat shingles and shorten the length and severity of the illness. Antivirals that can treat shingles includeTrusted Source:
- acyclovir
- valacyclovir
- famciclovir
Additionally, there are many home remedies people can try to help alleviate discomfort. These can include cool oatmeal baths, using calamine lotion, and trying to avoid stress.
Summary
While the link is unclear, some reports suggest a connection between COVID-19 vaccines and shingles eruptions. Although there is not enough evidence to suggest causality, some researchers indicate that the immune response to the vaccine may trigger a shingles flare. However, more research is necessary.
Shingles occurs after the reactivation of the varicella-zoster virus occurs due to an unknown trigger. Some evidence notes that changes to the immune system could be the trigger that reactivates the virus.
Despite this potential link, health experts advise that people still receive a COVID-19 vaccine as soon as possible. This is because the benefit of the vaccine outweighs the potential risks. Additionally, the vaccine cannot cause a person to acquire shingles. A person can only develop shingles if they have experienced a previous case of chickenpox or shingles.