Shingles, or herpes zoster, is a painful rash caused by reactivation of the varicella-zoster virus (the same virus that causes chickenpox) which remains dormant in nerve tissue after childhood infection.1 About one in three people in the United States develop shingles in their lifetime.1 The risk rises with age and with conditions that weaken the immune system, and women are affected more often than men.1 Most epidemiologic attention has focused on adults 50 and older, the group for whom vaccination has historically been recommended.2 More recently, the recombinant zoster vaccine was recommended for immunocompromised adults as young as 19, extending prevention efforts to younger patients at elevated risk.3 Adults under 50 also straddle an important divide in exposure history: the childhood chickenpox (varicella) vaccine was introduced in the United States in 1995, so people born from the mid-1990s onward are the first to reach adulthood largely in the vaccine era. Children vaccinated against chickenpox carry a lower risk of later shingles than those infected with the wild-type virus.1,4
To understand how common shingles is and how its frequency has changed, we examined the records of more than 85 million U.S. adults from two different angles. The first describes how common shingles diagnoses were across adult birth-year cohorts, calculating the rate of patients diagnosed with shingles during the study period by their birth year (Figure 1). The second narrows to adults aged 18 to 49 and follows new shingles cases over time (Figure 2).
Shingles diagnoses during the study period rose steeply across birth-year cohorts, tracking the well-established increase in shingles with age. The oldest cohort (born 1968–1975) had a rate of 181.9 per 10,000, roughly 26 times that of the youngest adults (born 2006–2008, 6.9 per 10,000). The single largest step down came at the 1991–1995 to 1996–2000 boundary, where the rate fell from 45.5 to 17.3 per 10,000 (a 62% decline), sharper than the change between any other adjacent cohorts. That break coincides with the first birth cohorts eligible for routine childhood chickenpox vaccination, though we did not evaluate whether patients had received the childhood chickenpox vaccine.
For the second view, we counted only new shingles cases, those among patients with no shingles diagnosed in the prior year and followed how they changed over time. Trends over time differed by age in both women and men. Rates among the youngest adults fell steadily, dropping by more than 50% among those aged 25–29, to roughly 3 per 10,000 by 2026. Rates declined in the 18–24 and 30–34 groups as well. This mirrors the birth-cohort pattern seen above: over the study window, these bands increasingly comprise people born after the introduction of the chickenpox vaccine, so part of the decline likely reflects those cohorts aging in. Because the 1995 rollout also offered catch-up vaccination to susceptible older children, this was a gradual transition rather than a sharp birth-year cutoff, extending a smaller effect into somewhat older groups, including part of the 35–39 band. The oldest groups, on the other hand, had a dip and rebound: rates fell through 2022 and 2023 before climbing to the top of their range by 2026, reaching about 16 per 10,000 among women aged 45–49. Part of that shape likely reflects pandemic-era health care use rather than true incidence: because the rate is measured among patients seen in outpatient care, the sharp drop in routine visits during 2020–2021 and their return afterward can move the measured rate up and then down on their own. Women and men had similar rates in the youngest groups, with women’s rates increasingly exceeding men’s in the older groups.
