A Herpes Infection May Be Linked to the COVID Vaccine

Can you develop herpes zoster as a possible side effect of COVID-19 vaccination?

Several studies have suggested a link between COVID-19 vaccines and the herpes zoster virus, the virus that causes shingles. Here, experts weigh in on the risk of developing herpes zoster (HZ) infection following mRNA COVID-19 vaccination.

Cases of Herpes Zoster Infections Following COVID-19 Vaccination

One of the earliest reports of herpes zoster infection post COVID-19 vaccination was published in April 2021 in the journal Rheumatology. The study analyzed side effect data from 491 people with autoimmune inflammatory rheumatic diseases (AIIRD) who received the Pfizer-BioNTech vaccine.

The researchers found that six of the patients with AIIRD (or 1.2%) developed herpes zoster—aka shingles—within several days of receiving the vaccine. Four of the patients had rheumatoid arthritis, one had Sjogren's syndrome, and another had a connective disease. All of the patients were women, and five of the reactions happened after the first vaccine dose.

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The herpes zoster infection was mild in the majority of cases, although one patient had a case of herpes zoster ophthalmicus, which is when the virus impacts the eye. Five of the patients were treated with antiviral medication and had no symptoms up to six weeks later. Five of the patients completed their second dose of the vaccine without any other issues.

In February 2022, a study published in the British Journal of Clinical Pharmacology looked at the relative risk of HZ reporting in mRNA COVID-19 vaccine recipients compared to influenza vaccine recipients. Researchers used the database VigiBase, the World Health Organization (WHO) global database which contains about 27 million spontaneous reports of suspected adverse drug reactions collected by national drug authorities in more than 130 countries.

The authors concluded that, when compared to influenza vaccines, mRNA COVID-19 vaccines were associated with a significantly higher reporting of HZ, especially in patients over 40 years old. However, the researchers wrote, the HZ reactions following mRNA COVID-19 vaccination were usually mild and infrequent as reflected by the billions of doses of COVID-19 vaccine administered so far.

Several subsequent studies also reported a link between the COVID-19 vaccines and herpes zoster. A March 2022 study published in the American Journal of Ophthalmology Case Reports reported three cases of patients not on immunosuppressive therapy who presented with herpes zoster after COVID-19 vaccination. The authors wrote, "herpes zoster may be a side effect of mRNA vaccination against the Sars-CoV2 vaccine and requires further investigation."

In May 2022, a study published in the journal Cureus reported on 10 incidences of herpes zoster reactivation in people within 7-21 days of getting the COVID-19 vaccination. The study found that increased age was the most important risk factor for HZ reactivation, but other risk factors included immunocompromised states, such as HIV infection, trauma, stress, or concomitant diseases including malignancy, hepatic or chronic renal disease.

The Cureus authors wrote that the fundamental reason for HZ reactivation was unknown. However, with the HZ reactivation occurring within 1-21 days after vaccination, COVID-19 vaccination was a likely cause for the reactivation of latent HZ. None of the patients had any other risk factor for developing herpes zoster.

As the Cureus authors highlight, the incidence of herpes zoster infection after COVID-19 vaccination is not a common occurrence. At the time of their study, the authors noted that the United States Vaccine Adverse Event Report System (VAERS) had reported 2512 cases of HZ (1.3%) of total reported events after the BioNTech, Pfizer COVID-19 vaccine, 1763 cases (0.9%) after the Moderna COVID-19 vaccine, and 302 (0.7%) after the Johnson & Johnson COVID-19 vaccine.

Should You Worry?

It's easy to grow concerned when you hear the word "herpes" in the same sentence as "COVID-19 vaccine," but experts say that this is not as shocking—or surprising—as it seems at first. Here's what you need to know.

First, a Primer on Herpes Zoster

Herpes zoster is another word for shingles, i.e. an outbreak of a rash or blisters on the skin. It's triggered by the same virus that causes chickenpox, the varicella-zoster virus, the National Institute of Neurological Disorders and Stroke (NINDS) says. For the record: This is not the same thing as genital herpes or oral herpes; those two conditions are caused by different herpes viruses.

What Are the Symptoms of Herpes Zoster?

At first, people with shingles may have a burning, itching, numb, or tingling pain that can be severe, NINDS says. It usually happens on one side of the body. People develop shingles after they've had a previous chickenpox exposure. When the virus reactivates, it causes shingles.

After a few days, a rash of fluid-filled blisters will appear in one area on one side of the body, NINDS explains. Shingles most commonly shows up in a band called a dermatome that goes from one side of your midsection around your waistline.

The pain from shingles can vary—some people mostly itch; Others can have pain from a gentle touch.

How Can the COVID-19 Vaccine Cause Herpes Zoster?

It's important to point out that none of the studies prove the COVID-19 vaccine caused shingles. Instead, they found a link, and most of the study authors wrote that the association needs to be researched more. The Cureus authors wrote, "These cases highlight the significance of continuing to examine vaccine safety during the COVID-19 pandemic's ongoing mass vaccination campaign."

That said, this connection isn't shocking to health care providers. "People with autoimmune disorders that are on immunosuppressant medications are at higher risk of having shingles," infectious disease expert Amesh A. Adalja, MD, senior scholar at the Johns Hopkins Center for Health Security in Maryland, told Health. Vaccines can also impact the immune system, and "there have been reports of vaccines causing shingles in the past," said Dr. Adalja.

"This can happen with the flu vaccine and others," Richard Watkins, MD, an infectious disease specialist and a professor of internal medicine at the Northeast Ohio Medical University, told Health. And if someone already has an autoimmune condition, they may be at greater risk of shingles, said Dr. Adalja.

Dr. Adalja said, "this phenomenon can occur after the COVID-19 vaccine as it has with others."

How Concerned Should You Be About Getting Herpes Zoster From the COVID-19 Vaccine?

While it's possible to get herpes zoster after being vaccinated against COVID-19, Dr. Adalja explained that the overall risk is low—especially if you don't have an autoimmune condition.

Herpes zoster can be treated with antiviral medications (usually valaciclovir) and most people recover just fine, said Dr. Adalja.

If you're particularly concerned about your risk of developing shingles after getting the COVID-19 vaccine, said Dr. Adalja, you can talk to your health care provider about receiving the herpes zoster vaccine first. Just know this: Because the herpes zoster vaccine is recommended by the CDC for people who are 50 and older, it's unlikely your insurance will cover it if you're below that age.

If you believe that you have developed shingles, you should contact a health care provider as soon as possible, who will be able to diagnose shingles and provide appropriate treatment.

The information in this story is accurate as of press time. However, as the situation surrounding COVID-19 continues to evolve, it's possible that some data have changed since publication. While Health is trying to keep our stories as up-to-date as possible, we also encourage readers to stay informed on news and recommendations for their own communities by using the CDC, WHO, and their local public health department as resources.

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