Effects of herpes zoster vaccination and antiviral treatment on the risk of stroke: a systematic review and meta-analysis

Background

Evidence suggests that there is an increased risk of stroke after herpes zoster (HZ). However, reports on the effects of HZ vaccination (HZV) and antiviral treatment on stroke risk are inconsistent. Thus, we examined these associations in a meta-analysis.

Methods

To identify relevant studies, we searched three databases for articles published up to January 2023. Random-effect models were examined to determine overall pooled estimates and 95% confidence intervals (CIs).

Results

This review included 12 observational studies (six on HZV and seven on antiviral treatment). When comparing vaccinated and unvaccinated patients, vaccination was found to be associated with a lower risk of stroke (OR, 0.78; 95% CI 0.68-0.9; P = 0.001). A meta-analysis of self-controlled case series (SCCS) revealed evidence of a reduced OR in individuals who received the vaccine (OR, 1.14; 95% CI 0.94-1.37; P = 0.181) compared with unvaccinated individuals (OR, 1.36; 95% CI 1.15-1.61; P < 0.001). Compared with untreated patients, antiviral therapy was not associated with a reduced risk of stroke (OR, 1.13; 95% CI 0.94-1.36; P = 0.201). The meta-analysis of the SCCS showed no evidence of a reduced OR in individuals who received antiviral therapy (OR, 1.33; 95% CI 1.17-1.51; P < 0.001) compared to untreated individuals (OR, 1.45; 95% CI 1.25-1.69; P < 0.001).

Conclusions

This meta-analysis suggests that the HZV, but not antiviral treatment, decreases the odds of developing stroke.

Amenamevir, a novel helicase-primase inhibitor, for treatment of herpes zoster: A randomized, double-blind, valaciclovir-controlled phase 3 study

Amenamevir is a potent helicase-primase inhibitor and a novel class of antiviral agent other than nucleoside compounds, such as aciclovir, valaciclovir and famciclovir. This study is the first randomized, double-blind, valaciclovir-controlled phase 3 study to evaluate the efficacy and safety of amenamevir in Japanese patients with herpes zoster when treated within 72 h after onset of rash. A total of 751 patients were randomly assigned to receive either amenamevir 400 mg or 200 mg p.o. once daily or valaciclovir 1000 mg three times daily (daily dose, 3000 mg) for 7 days. The primary efficacy end-point was the proportion of cessation of new lesion formation by day 4 ("day 4 cessation proportion"). The day 4 cessation proportions for amenamevir 400 and 200 mg and valaciclovir were 81.1% (197/243), 69.6% (172/247) and 75.1% (184/245), respectively. Non-inferiority of amenamevir 400 mg to valaciclovir was confirmed by a closed testing procedure. Days to cessation of new lesion formation, complete crusting, healing, pain resolution and virus disappearance were evaluated as secondary end-points. No significant differences were observed in any of the treatment groups. Amenamevir 400 and 200 mg were well tolerated as well as valaciclovir. The proportions of patients who experienced drug-related adverse events were 10.0% (25/249), 10.7% (27/252) and 12.0% (30/249) with amenamevir 400 and 200 mg and valaciclovir, respectively. In conclusion, amenamevir 400 mg appears to be effective and well tolerated for treatment of herpes zoster in immunocompetent Japanese patients.

Peripheral Stimulation for Treatment of Trigeminal Postherpetic Neuralgia and Trigeminal Posttraumatic Neuropathic Pain: A Pilot Study

OBJECTIVE:

Trigeminal neuropathic pain (TNP) after facial trauma or herpes zoster infection is often refractory to treatment. Peripheral nerve stimulation has been used to treat occipital neuralgia; however, efficacy in controlling facial TNP or postherpetic neuralgia is unknown. A retrospective case series of patients who underwent subcutaneous placement of stimulating electrodes for treatment of V1 or V2 TNP secondary to herpetic infection or facial trauma is presented.

METHODS:

Ten patients received implanted subcutaneous pulse generators and quadripolar electrodes for peripheral stimulation of the trigeminal nerve supraorbital or infraorbital branches. Long-term treatment results were determined by retrospective review of medical records (1998–2003) and by independent observers interviewing patients using a standard questionnaire. Surgical complication rate, preoperative symptom duration, degree of pain relief, preoperative and postoperative work status, postoperative changes in medication usage, and overall degree of therapy satisfaction were assessed. Mean follow-up was 26.6 ± 4.7 months.

RESULTS:

Peripheral nerve stimulation provided at least 50% pain relief in 70% of patients with TNP or postherpetic neuralgia. Medication use declined in 70% of patients, and 80% indicated that they were mostly or completely satisfied with treatment overall. There were no treatment failures (&lt; 50% pain relief and a lack of decrease in medication use) in the posttraumatic group, and two failures (50%) occurred in the postherpetic group. The complication rate requiring reoperation was 30%.

CONCLUSION:

Peripheral nerve stimulation of the supraorbital or infraorbital branches of the trigeminal nerve is an effective method for relief of TNP after facial trauma or herpetic infection. A prospective trial using this novel approach to treat these disorders is thus warranted.

Oral antivirals revisited in the treatment of herpes zoster: what do they accomplish?

Oral antiviral agents currently represent the most important therapeutic keystone in the treatment of herpes zoster. Three oral antiviral agents are available for the treatment of herpes zoster: acyclovir, its derivative valacyclovir, and famciclovir. Meta-analysis of published data has shown that oral acyclovir significantly reduces various herpes zoster-related symptoms as well as the duration, intensity and prevalence of zoster-associated pain (ZAP). However, this drug does not influence postherpetic neuralgia. The newer agents famciclovir and valacyclovir exhibit a better oral bioavailability than acyclovir. These agents have demonstrated similar efficacy to acyclovir with ZAP and they require less frequent administration. When initiated within 72 hours, oral antiviral therapy of herpes zoster is beneficial in selected, elderly immunocompetent patients, reducing the duration and intensity of ZAP and providing more rapid skin lesion healing. Oral antivirals are also of benefit in immunocompromised patients with uncomplicated herpes zoster. However, signs of cutaneous and visceral dissemination should be monitored; if signs occur, intravenous antiviral therapy is indicated.