Global, regional, and national burden of varicella-zoster infections in adults aged 70 years and older from 1997 to 2021: Findings from the Global Burden of Disease Study.

BACKGROUND

Varicella-zoster virus (VZV) infection gives rise to varicella (chickenpox) and herpes zoster (HZ, shingles). Primary VZV infection results in varicella, while HZ occurs as a consequence of latent VZV reactivation. Older adults are at a significantly elevated risk of HZ because of age-related immune senescence. This study was designed to evaluate the global burden and trends of VZV-related diseases (VHZ: varicella and HZ) among adults aged ≥70 years from 1997 to 2021 and to explore the influencing factors. In this specific age group, VHZ predominantly refers to HZ.

METHODS

Data from the Global Burden of Diseases, Injuries, and Risk Factors Study 2021 were employed to estimate the incidence, disability-adjusted life years (DALYs), and rates of VHZ in older adults. Estimated annual percentage changes were utilized to quantify trends, and demographic decomposition analysis was conducted to determine the impacts of population aging, growth, and epidemiological changes.

RESULTS

In 2021, a total of 4,539,519 new VHZ cases were reported globally among older adults, with an incidence rate of 918.2 per 100,000. The global DALYs attributable to VHZ amounted to 113,013, corresponding to a DALY rate of 22.9 per 100,000. From 1997 to 2021, although the incidence rate increased slightly, the DALY rate declined significantly. Population growth was the main driver of the increase in the number of cases, whereas enhanced disease management contributed to the reduction in DALYs.

CONCLUSIONS

From 1997 to 2021, the incidence of VHZ in adults aged ≥70 years increased marginally due to population growth, while the disease burden (measured by DALYs) decreased, probably attributed to improved disease management strategies. These trends were particularly evident in regions with a high Socio-Demographic Index (SDI), potentially associated with vaccination efforts, and significant reductions in DALYs were observed in low- and middle-SDI regions, likely owing to advancements in healthcare.