Increasing Cases of Shingles in the Eye Raise Key Questions.

Abstract

At first look, Nakul Shekhawat, MD, MPH, thought the explanation for his research results was obvious. Shekhawat and his colleagues at the University of Michigan found that the incidence of herpes zoster ophthalmicus (HZO)—shingles of the eye—had tripled in the United States from 2004 to 2016. He chalked it up to the aging US population. “That’s what you would think,” he said. It’s a reasonable assumption. Virtually every US-born adult aged 40 years or older has been infected with varicella zoster virus, which causes chickenpox. Although universal varicella vaccination was introduced in 1995, millions of older adults have waning cell-mediated immunity that leaves them vulnerable to reactivation of varicella virus, which causes shingles. Older age is a prominent risk factor for the condition, which usually causes a painful, itching unilateral rash on the chest and back. Shekhawat’s data showed that older age is a risk factor for HZO, too. In addition to age as a risk factor, his data also suggested that women were more likely than men to develop HZO as were white adults compared with black, Asian, and Latino adults—the same demographic patterns as with shingles. Among the study population of 21 million adults enrolled in United Healthcare insurance plans, HZO incidence increased from 9.4 cases per 100 000 population in 2004 to 30.1 cases per 100 000 in 2016. The finding of increased HZO incidence persisted when Shekhawat and his colleagues adjusted their analysis for age, race, and sex, raising some important questions. For example, why is the incidence of HZO and shingles increasing? “Diseases don’t usually double or triple over a 12-year time span,” said Shekhawat, who is now in a cornea fellowship program at the Johns Hopkins Wilmer Eye Institute. Several theories exist, but study results are mixed. Another central issue is why vaccination against shingles isn’t more widespread. The Centers for Disease Control and Prevention (CDC) reported that in 2016, about 33% of US adults aged 60 years or older had been vaccinated with Zostavax, a live, attenuated virus vaccine that was licensed in 2006 for adults aged 50 years and older. Shingrix, a more effective recombinant vaccine, was licensed in 2017. The Advisory Committee on Immunization Practices (ACIP), which offers guidance to the CDC, recommends Shingrix for immunocompetent adults aged 50 years or older. For those who aren’t able to receive Shingrix, ACIP recommends Zostavax for immunocompetent adults aged 60 years or older. “It has been a big problem that primary care doctors haven’t recognized the importance of vaccination against [shingles], and I’m hoping they will do better now that we have a more effective vaccine, said Elisabeth Cohen, MD, a professor of ophthalmology at the New York University (NYU) School of Medicine and NYU Langone Health. Complications from HZO, in which the varicella virus reactivates in the ophthalmic division of the trigeminal nerve, can be severe. The virus may cause pronounced eyelid edema or skin lesions around the eye. The cornea or other parts of the eye may be affected. Other complications include glaucoma, retinal necrosis, and blindness, as well as an increased risk of stroke. Cohen is well aware of the consequences. Her own vision loss from HZO while still in her 50s caused her to give up a distinguished career as a cornea surgeon.