Does oral antiviral suppressive therapy prevent recurrent herpes labialis in children?

Bacillus Calmette-Guérin vaccination for protection against recurrent herpes labialis: a nested randomised controlled trial

Background

Recurrences of herpes simplex virus (HSV) in the orofacial region (herpes labialis or cold sores) impact quality-of-life. We aimed to study whether the bacille Calmette-Guérin (BCG) vaccine can attenuate cold sore recurrences through off-target immunomodulatory effects.

Methods

In this nested randomised controlled trial within the multicentre, phase 3 BRACE trial, 6828 healthcare workers were randomised in 36 sites in Australia, the Netherlands, Spain, the United Kingdom and Brazil, to receive BCG-Denmark or no BCG (1:1 ratio using a web-based procedure) and followed for 12 months with 3-monthly questionnaires. Exclusion criteria included contraindication to BCG vaccine or previous vaccination with BCG within the past year, any other live-attenuated vaccine within the last month, or any COVID-specific vaccine. The intervention group received one intradermal dose of 0.1 mL of BCG-Denmark corresponding to 2-8 x 105 colony forming units of Mycobacterium bovis, Danish strain 1331. The primary outcome was the difference in restricted mean survival time (i.e., time to first cold-sore recurrence), in participants with frequent recurrent herpes labialis (≥4 recurrences/year), analysed by intention-to-treat. Secondary outcomes addressed additional questions, including analyses in other sub-populations. Adverse events were monitored closely during the first 3 months and were reported in all participants who received one dose of study drug according to intervention received. The BRACE trial is registered with ClinicalTrials.gov, NCT04327206.

Findings

Between March 30, 2020 and February 18, 2021, 84 individuals with frequent recurrent cold sores were randomly assigned to BCG (n = 38) or control (n = 46). The average time to first cold-sore recurrence was 1.55 months longer in the BCG group (95% CI 0.27-2.82, p = 0.02) than the control group (hazard ratio 0.54, 95% CI 0.32-0.91; intention-to-treat). The beneficial effect of BCG was greater in the as-treated population (difference 1.91 months, 95% CI 0.69-3.12, p = 0.003; hazard ratio 0.45, 95% CI 0.26-0.76). In prespecified subgroup analyses, only sex modified the treatment effect (interaction p = 0.007), with benefit restricted to males. Over 12 months, a greater proportion of participants in the BCG group compared with the control group reported a decrease in duration (61% vs 21%), severity (74% vs 21%), frequency (55% vs 21%), and impact on quality of life (42% vs 15%) of cold sore recurrences. In participants who had ever had a cold sore, there was also a decrease in self-reported burden of recurrences in the BCG group. In participants who had never had a cold sore, there was an increased risk of a first episode in the BCG group (risk difference 1.4%; 95% CI 0.3-2.6%, p = 0.02). There were no safety concerns.

Interpretation

BCG-Denmark vaccination had a beneficial effect on herpes labialis, particularly in males with frequent recurrences, but may increase the risk of a first cold sore.

Funding

Bill & Melinda Gates Foundation, the Minderoo Foundation, Sarah and Lachlan Murdoch, the Royal Children's Hospital Foundation, Health Services Union NSW, the Peter Sowerby Foundation, SA Health, the Insurance Advisernet Foundation, the NAB Foundation, the Calvert-Jones Foundation, the Modara Pines Charitable Foundation, the UHG Foundation Pty Ltd, Epworth Healthcare, and individual donors.

Does bacillus Calmette-Guérin vaccine prevent herpes simplex virus recurrences? A systematic review

Recurrent infections with herpes simplex virus (HSV) in the orofacial (cold sores), ocular or genital region are common and sometimes disabling, calling for an effective preventive intervention. The bacillus Calmette-Guérin (BCG) vaccine has beneficial off-target effects that might impact recurrence of HSV infections. In this systematic review, Medline, EMBASE, and PubMed were searched in June 2020; 16 articles were deemed relevant comprising eight animal and eight human studies (301 patients). In animals, BCG administration led to a 1.9 to 5.5-fold increase in survival rate following HSV challenge (vaginal, corneal, or intraperitoneal inoculation). This beneficial effect was influenced by the dose of BCG (higher better), mode of administration (intradermal better than intraperitoneal), and the interval between vaccination and viral challenge (at least 6 days required). In nonrandomized human studies (that failed to control for a placebo effect), BCG vaccination appeared beneficial in 78% of adults with recurrent herpes genitalis or labialis, with 37% being recurrence-free for an extended period, 41% experiencing less frequent or severe episodes, and only 22% reporting no change. This clinical benefit is consistent with the findings of immunological sub-studies. In the two studies restricted to recurrent herpes labialis, 94% appeared to benefit from BCG. The one randomized controlled trial used an intervention in the control group that has immunomodulatory effects thus limiting interpretation. In conclusion, BCG vaccine is a potential, safe, affordable and readily available candidate intervention to decrease the high burden of disease associated with HSV infection and recurrences, but properly controlled randomized trials are required.

Antiviraux chez l’enfant en pratique de ville : infections herpétiques, varicelle, grippe

Les infections liées à l’herpès virus humain (HSV), au virus de la varicelle et du zona (VZV) et au virus de la grippe (Influenza A et B) sont très fréquentes en pédiatrie et sont le plus souvent bénignes avec une guérison spontanée. L’utilisation des antiviraux antigrippaux (inhibiteurs de neuraminidase) a été étudiée dans de larges essais randomisés et fait l’objet de recommandations nationales et internationales. Celle des anti-HSV et anti-VZV n’a pas fait l’objet d’études de la même ampleur et de ce fait, leur prescription est plus discutée avec des bénéfices moins bien définis et variables (à l’exception des infections néonatales et/ou neuro-méningées). L’objectif de cette mise au point est donc de proposer une synthèse des données disponibles dans la littérature concernant les indications des antiviraux en pratique de ville pour les infections liées à l’HSV (gingivostomatite, herpès récurrent, faux panaris herpétique), au VZV (varicelle, zona) et à la grippe.

Viral infections of oral cavity

Viral infections of the oral cavity usually manifest as either ulceration or blistering presentation of oral tissues. Oral viral infections are encountered in dental practice but received less clinical interest due to the lesser frequency of patients and diagnostic challenges. The clinical presentation, pathogenic mechanism, investigations, and management of oral viral infections are integrated into the article which will enable general dentists to develop critical thinking processes on differential diagnosis and management through a multidisciplinary approach with specialist dentists.