# Use of antiviral drugs and incidence of Parkinson’s disease in Taiwan

## TL;DR

This study suggests that antiviral drugs may reduce the risk of Parkinson’s disease in people with herpes zoster, especially in women.

## Contribution

The study provides new evidence that antiviral treatment for herpes zoster is associated with a reduced risk of Parkinson’s disease.

## Key findings

- Herpes zoster is associated with a slight increase in Parkinson’s disease risk (aHR 1.05).
- Antiviral drug use is linked to a 16% lower risk of Parkinson’s disease (aHR 0.84).
- The protective effect of antiviral drugs was consistent across age and sex groups.

## Abstract

Patients infected with herpes zoster might be at risk for Parkinson’s disease (PD). However, antiviral drugs may impede viral deoxyribonucleic acid (DNA) synthesis. This study aimed to determine whether the currently observed association between herpes zoster and PD is consistent with previous findings, and whether antiviral drug use is associated with PD. This retrospective cohort study used the Longitudinal Generation Tracking Database. We included patients aged 40 years and above and applied propensity score matching at 1:1 ratio for study comparability. PD risk was evaluated using Cox proportional hazards regression methods. A total of 234,730 people were analyzed. The adjusted hazard ratio (aHR) for PD in patients with herpes zoster was 1.05. Furthermore, the overall incidence of PD was lower in those treated with antiviral drugs than in the untreated ones (3.17 vs. 3.76 per 1,000 person-years); the aHR was 0.84. After stratifying for sex or age, a similar result was observed. In conclusion, herpes zoster may increase the risk of PD, particularly among females, but receiving antiviral treatment reduces the risk by 16%. Therefore, using antiviral drugs may help prevent PD. However, additional research is required to determine the underlying mechanism(s).