Herpes zoster after COVID-19 as a marker of long-term neuro-ophthalmic risk

The TriNetX study by Lin et al. demonstrated that reactivation of herpes zoster (HZ) after COVID-19 was associated with a sustained increase in the risk of uveitis and optic neuritis over 3 years.1 An under-emphasized but clinically important insight emerges when the supplementary data are interpreted in absolute terms. Uveitis occurred in 0.6% of exposed patients compared to 0.1% of controls,1 corresponding to a number needed to harm of approximately 200, while optic neuritis showed a smaller absolute excess risk. These figures contextualize the high hazard ratios and indicate that, although uncommon, these events are clinically meaningful because they may result in irreversible visual loss, thereby supporting targeted rather than universal ophthalmic surveillance. Beyond ocular outcomes, patients with post-COVID HZ exhibited higher rates of reinfection and hospitalization,1 suggesting that HZ identified a subgroup with persistent systemic vulnerability rather than acting solely as a local viral trigger. The stability of ocular risk across landmark analyses up to three years supported a durable immune perturbation,1 consistent with emerging models of long COVID characterized by chronic immune activation, viral persistence and autoimmunity.2–4