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Prevention is key to keeping our eyes healthy, and the recombinant shingles vaccine represents an important advance in this context. Shingles, also known as 'shingles', is a condition that can cause intense pain and complications, especially in older adults. The recombinant vaccine offers significant protection, drastically reducing the risk of occurrence and recurrence of this infection. Recommended for those over the age of 50, the vaccine is also a safe option for those who have already received the previous version.

Herpetic disease

Ophthalmic herpes zoster infection is very common because the virus, which is the same one responsible for the childhood chickenpoxOnce contracted, it remains latent in the nerve cell bodies, without causing any symptoms.

Years or decades after a chickenpox infection, the virus can spread from one or more ganglia along the nerves of an affected segment and infect the corresponding dermatomere, as an area of skin served by a particular spinal nerve is defined, causing a painful rash.

Ophthalmic herpes zoster

Ophthalmic herpes zoster (HZO) is caused, as mentioned above, by the reactivation of the latent varicella-zoster virus and typically results in a painful eruption with blisters in the area corresponding to the ophthalmic branch of the trigeminal nerve, also affecting the eyes.

It is estimated that ophthalmic herpes constitutes approximately 10-20% of the total herpetic infections.

Risk factors

Risk factors for the development of this infection, which can also involve the nose, include:

- advanced age

- conditions of immuno-compromise

- the presence of comorbidities.

A number of studies have recently been published concerning experimental evidence of a potential causal correlation between ophthalmic herpes zoster and vaccination against COVID-19, which would appear to lead to the onset of a viral infection that can also affect the eye.

Symptoms

A characteristic manifestation of ophthalmic herpes zoster is intense pain in the eye, characterised by a stabbing pain that also radiates to the periocular area and localised pain in the acute phase of the vesicular eruption.

Approximately half of all patients with ophthalmic herpes zoster may develop postherpetic neuralgia with ophthalmic involvement. This condition is characterised by moderate to severe facial pain that may persist for more than 3 months after the onset of the skin lesion.

Specific features of this neuropathy are the presence of continuous, spontaneous burning pain with electric shock-like twinges in a paroxysmal phase, allodynia (i.e. the painful impulse felt by the person following an innocuous stimulus) and hyperalgesia (which defines the increased response to a stimulus capable of provoking painful sensations).

The quality of life in these patients is therefore particularly compromised and it is therefore necessary to find strategies that can alleviate the painful symptoms and prevent the recurrence of the infection.

Treatment

In the management of herpes zoster infection, especially in advanced age, first-line treatment involves the oral administration of acyclovir or systemic antiviral analogues from the early stages of infection, although the ability of these drugs to reduce the risk of postherpetic neuropathy remains controversial.

In addition to antiviral treatment, it is essential to administer specific pain relief therapy, most often with analgesic drugs, including tricyclic antidepressants, antiepileptics, opioids and topical analgesics.

If oral therapy proves insufficient, surgical treatments, such as temporary blockade of local nerve sensitivity to provide immediate short-term pain relief, may also be considered.

Preventing relapses

Herpetic disease, as we have seen, is not a 'single-stage' disease, but rather a recurrent infection that may be accompanied by chronic post-neuralgia pain.

This eventuality makes it relevant for ophthalmologists and health authorities to promote the vaccination of populations against the zoster virus.

The use of the vaccine is desirable for a number of concomitant reasons.

Firstly, throughout the developed world, there has been a progressive extension of average life expectancy and, therefore, an increase in the elderly component of the population, which is more likely to experience herpetic infection.

Secondly, the elderly tend to be more susceptible to zoster infection due to a number of age-related conditions such as inherent immuno-senescence, which can be compounded by possible immunosuppression from pharmacotherapy or diseases that compromise the immune system such as AIDS.

In addition, it must be considered that varicella vaccination administered at a young age actually leads to less risk-exposure within the community and thus fewer infectious situations that would serve to maintain cell-mediated immunity.

The question of whether it is appropriate to vaccinate and which age is to be recommended is quite complex. The study for the prevention of zoster (Shingles Prevention Study), published in the New England Journal of Medicine in 2005, firstly demonstrated the vaccine's safety and efficacy in reducing both the incidence of herpetic infection and the risk of postherpetic neuralgia.

The two types of vaccine

Two types of vaccine have been developed over time to immunise against the varicella zoster virus:

• Attenuated vaccine: made from the herpes zoster virus rendered harmless and thus unable to transmit the disease to the patient.
• Recombinant vaccine: realised through recombinant DNA technology.

Importance of the Recombinant Vaccine

The recombinant vaccine against herpes zoster represented a significant step in the prevention of complications associated with this painful disease.

Protection from Postherpetic Neuralgia

The postherpetic neuralgia is one of the most feared and debilitating complications of shingles, not least because it is characterised by persistent pain even after the initial rash has healed.

The vaccine works by stimulating a robust immune response that prevents not only the primary infection, but also the long-term consequences. Studies have shown that vaccinated persons have a lower incidence of neuralgia, resulting in an improvement in their quality of life.

In addition, the prevention of postherpetic neuralgia is crucial to avoid the prolonged use of pain-relieving drugs that may have undesirable side effects, especially in the elderly.

Efficacy of the Recombinant Vaccine

The recombinant vaccine stands out for its high efficacy in preventing shingles and its complications. We analyse the data demonstrating its superiority over other available solutions.

Success rates

Clinical studies indicate that the recombinant vaccine is highly effective, with high success rates. In adults aged 50 to 69 years, the efficacy exceeds 97%, while in adults aged 70 years and older, it stands at 90%.

These results demonstrate the vaccine's ability to activate the immune system in a powerful way, providing lasting protection. The immunogenicity of the vaccine is a key factor in its success.

Comparison with Mitigated Live Vaccine

The table below summarises the results comparing recombinant vaccine and live attenuated virus vaccine.

The recombinant vaccine has shown better results than the live attenuated virus vaccine, with a longer duration of protection and higher efficacy. This makes the recombinant vaccine the preferred choice for prevention.

Vaccination Recommendations

The guidelines for vaccination with the recombinant vaccine are designed to select the most suitable people to receive this form of protection, at the appropriate time.

Age and Eligibility Criteria

Vaccination is recommended for adults immunocompetent aged 50 years or older. This recommendation applies regardless of whether the individual has had herpes zoster in the past or has received the live attenuated virus vaccine.

This approach ensures that a broad population can benefit from the protection offered by the recombinant vaccine. People with a history of shingles are also eligible, as the vaccine can prevent recurrences and future complications.

In summary, suitability is primarily based on age and general health, with the aim of maximising shingles prevention.

Time Distance Between Doses

The recombinant vaccine is administered in two doses0.5 mL each. Doses are administered 2-6 months apart.

1. The first dose initially activates the immune system, creating a protective response.
2. The second dose strengthens the protection, ensuring a more robust and lasting immune response.

This timing allows maximum benefit from the vaccine, ensuring an optimal level of protection against shingles.

Safety and immunogenicity

The safety and immune efficacy of the recombinant vaccine have been extensively studied. The results reassure the use of the vaccine in the target population.

Clinical Studies and Results

Numerous clinical studies confirmed the safety of the recombinant vaccine, with results showing a strong and lasting immune response.

Study participants reported minimal, generally mild and transient adverse reactions. This indicates a good tolerability profile, which is crucial for the widespread acceptance of the vaccine.

Clinical data emphasise the importance of vaccination as a preventive measure against herpes zoster, especially in older adults, and the opportunity to revaccinate patients who had already been vaccinated with the live attenuated virus vaccine with the recombinant vaccine has also been demonstrated.

Experiences of Vaccinated Patients

The experiences of patients who have received the recombinant vaccine are generally positive:

• Reduction of symptoms: Many patients report a drastic decrease in symptoms upon exposure to the virus.
• Minimal reactions: Adverse reactions are mainly local and of short duration, such as pain at the injection site.
• Improving the quality of lifePatients appreciate the reduction of anxiety related to the possibility of developing serious complications.

Patient testimonies reinforce the importance of the vaccine as an effective and well-tolerated prevention tool.

About shingles eye infection see also:

Ophthalmic herpes zoster and pain therapy - Oculista Italiano

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• Miserocchi E, Fogliato G, Bianchi I, et al. Clinical features of ocular herpetic infection in an Italian referral centre. Cornea. 2014 Jun;33(6):565-70.