Herpes zoster ophthalmicus (HZO) is increasing in the United States, particularly in people who are middle-aged, prompting some to wonder if greater efforts should be made to vaccinate eligible adults 50 and older, researchers from the University of California say.

Their study, published in Ophthalmology, found a 3.6% overall increase in HZO cases from 1994 to 2018. Since 2008, HZO has declined in people younger than 21 and older than 60 but increased at a lower rate in middle-aged adults, the investigators said.

The researchers used data from administrative claims and electronic healthcare records. Patients who had no prior history but were given a new code for HZ and HZO were included. The study calculated the incidence rate of HZO by year, 10-year age groups, sex, race and geographic region.

During the 24-year study period, investigators found 633,474 cases of HZ and 49,745 cases of HZO (7.9%). Additionally, the incidence of HZO increased from 1994 to 2018 by an estimated 1.1 cases per 100,000 persons/years annually. The researchers noted HZO increased in all ages over 10 until 2007. After that, the study reported a decline in individuals younger than 21 and older than 60; a stabilization in individuals 21 to 30; and a slower increase in subjects aged 31 to 60. 

The research team also found females and Caucasians were at higher risk of developing HZO.

Looking at geography, HZO rates were highest in the Northeast and lowest in the West, which may be tied to vaccinations, the researchers noted. A 2014 analysis found vaccination rates were the second lowest in the Northeast at 30.3% and highest in the West at 37.4%, they said in their paper on the study. 
More research on earlier vaccination is warranted, the researchers suggested.

“Given the potential shift in HZO burden towards middle-aged individuals, it is crucial for clinicians to support vaccination efforts for individuals 50 years of age and older. These results also raise the question of whether HZ vaccine recommendations should be reevaluated for individuals in younger age groups,” the researchers wrote in their paper.