shingles virus
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Getting the recombinant zoster (shingles) vaccine (RZV), or Shingrix, if you have had an ocular shingles event, may increase your risk of experiencing a second event, a recent study shows.

Ocular shingles refers to all shingles that manifest in the eye area. Milder cases of ocular shingles typically occur near the eyelids, while more severe cases may cause inflammation inside the eyes and potentially lead to blindness.

Researchers at the University of California (UC)-San Francisco found that, compared to unvaccinated people with a history of ocular shingles, those who receive the RZV have a 93 percent higher rate of developing ocular shingles again.

"It's not a huge increased risk," lead author Dr. Nisha Acharya, director of the Uveitis and Ocular Inflammatory Disease Service at UC-San Francisco, told The Epoch Times. "To my knowledge, it's the first data that we have on risks of reactivation following zoster vaccination for this patient population who already have the disease. I think it raises some questions," she said.

Reactivation of Ocular Shingles May Not Be Viral Reactivation

Shingles is caused by the chickenpox (varicella) virus. After a person gets chickenpox, the virus retreats into the nerves in the body and becomes dormant. If the virus lies dormant in the nerves going into the eye, it can later cause ocular shingles during viral reactivation.

Around 10 percent to 20 percent of people who contract shingles will develop ocular shingles, according to the American Academy of Neurology.

While shingles recurrence on the skin is common and usually a sign of the latent virus acting up, there may be another mechanism to explain some ocular recurrences: "Your immune system reacting against some remnant of the prior infection," Dr. Acharya said.

Since the vaccine activates the immune system, it may cause the body to react and target viral-related remnants in the eye, leading to a recurrence of ocular shingles, she added.

"There may not be active, replicating virus anymore, but you can sometimes have inflammation because your immune system is reacting against what we call viral antigens, or parts of the virus or segments related to that prior infection," Dr. Acharya explained.

What This Means for Vaccine Recommendations

Dr. Acharya said it is still too early to conclude whether current vaccine recommendations should be changed.

Since 2020, the RZV has been the only available shingles vaccine in the United States.

The U.S. Centers for Disease Control and Prevention (CDC) recommends that all people over 50 and immunocompromised people over 19 should get vaccinated, even if they have a history of shingles.

"There hasn't really been any compelling evidence that having an episode of zoster will prevent you from getting a subsequent episode," Dr. Rafael Harpaz, a retired infectious disease epidemiologist from the CDC, who specialized in herpes zoster and varicella virus, told The Epoch Times.

"In that respect, since the vaccine definitely does prevent zoster, it is more effective than actually getting zoster itself," he added.

However, since no data exist on RZV safety in patients with a history of ocular shingles, some ophthalmologists have been reluctant to recommend vaccinations to patients with ocular shingles, the authors discussed in their study.

Dr. Acharya's team evaluated over 16,400 patients with ocular shingles in their database. Those who went on to get RZV vaccines were tracked for up to 90 days and compared against those with a history of ocular shingles but who did not get vaccinated.

Only those prescribed medication due to a recurring ocular shingles diagnosis were considered to be recurring cases. The authors reported that recurrence of ocular shingles eight weeks after vaccination "was 37.7 per 1000 person-years compared with 26.2 per 1000 person-years in the [unvaccinated] group."

Dr. Acharya said the finding does not suggest that people who previously contracted the virus should not be vaccinated.

"The question is, what is the benefit versus risk in these patients? We found more recurrences, but we don't know how severe these recurrences were. What was the consequence to the patient? ... I don't have that data because this study used insurance claims data," said Dr. Acharya.

The research addressed issues that are hard to accurately measure, and the associations that the study found "were statistically modest," said Dr. Harpaz, "so it was appropriate that they (the researchers) were cautious" in their interpretation of the findings.

Dr. Acharya added that the study findings did not discount the benefits of RZV in preventing new shingles cases. She said she has seen many cases of severe ocular shingles that could have been prevented had the patient chosen to get the shingles vaccine prior to infection.

Unlike Zostavax, a live, attenuated vaccine discontinued in 2020, the RZV is a non-live vaccine that only exposes recipients to the proteins of the varicella virus.

Zostavax, apart from its comparatively transient effectiveness, also caused unexplainable cases of shingles in immunocompetent people.

COVID Vaccines and Shingles Recurrence

Since the rollout of the COVID-19 vaccines, some case studies and larger observational studies have reported a recurrence of shingles and ocular shingles following COVID-19 vaccination. However, many studies have come to the opposite conclusion.

Dr. Harpaz said that he could only speculate about whether there is a link between COVID-19 vaccines and shingles recurrence.

"[Herpes zoster] is really mysterious; we don't really understand what causes zoster," he said.

"Obviously, we know that age is an important risk factor, and immunosuppression is a real factor. But there are an awful lot of immune-competent people without any problems in their immunity who developed zoster, and there are certain things that seem to really prime you for getting an episode of zoster — for instance, trauma."

Nevertheless, some clinicians have observed increased shingles flare-ups among their patients, which they have attributed to COVID-19 infections or vaccinations.