What is it?

Herpes zoster (shingles) is caused by a reactivation of the varicella zoster virus (VZV), the same virus that causes varicella infection (chickenpox). After a person recovers from a chickenpox infection, the virus stays dormant (inactive) within the dorsal root ganglia of the spinal nerves but can later be reactivated, presenting as shingles. It occurs more commonly in adults > 50 years, those who are immunocompromised and those who were diagnosed with a varicella infection < 1 year of age.

Symptoms and complications

Shingles is a painful, vesicular rash. It usually presents on one side of the face or body, typically appearing in a dermatomal distribution (an area of skin supplied by a spinal nerve). Prior to the emergence of rash, there is often pain, itching, or tingling in the area where the rash will develop. This may happen anywhere from 1 to 5 days before the rash appears. Other symptoms of shingles can include fever, headache, chills, and malaise (generally feeling unwell). The blisters will typically scab over in 7 – 10 days after onset and resolve within 2 – 4 weeks.

Post-herpetic neuralgia (PHN) is the most common complication of a shingles infection and is more likely to occur in older people (> 70 years of age) than younger people. PHN is a chronic neuropathic pain which can affect 1 in 4 cases of shingles diagnosed in those > 80 years. It can persist for months to years with pain control being difficult to manage, impacting quality of life.

Other complications of shingles include skin pigmentation and scarring, secondary bacterial infections, as well as herpes zoster opthalmicus (eye involvement with differing degrees of symptoms including conjunctivitis, ocular-cranial nerve palsies, loss of vision and debilitating pain).

How is it transmitted?

Shingles is the reactivation of a previous VZV infection and therefore it cannot be passed from one person to another. The lifetime risk of a reactivation of the VZV virus to cause shingles is 20-30% and affects half of all people who live to 80 years. Repeated shingles infections occur in around 5% of immunocompetent people.

Exposure to the fluid filled vesicles of a shingles rash can result in a VZV infection (as chickenpox) in a seronegative person (a person with no previous VZV disease). Shingles is less contagious than chickenpox and the risk of a person with shingles spreading the virus is low if the rash is covered.

Am I already protected?

Shingles can only develop in people who have previously been infected with VZV.

The lifetime risk of a reactivation of the VZV virus to cause shingles is 20-30% and affects half of all people who live to 80 years. Repeated shingles infections occur in around 5% of immunocompetent people.

Prevention

The only way to reduce the risk of developing shingles and its complications is through vaccination.

There are currently 2 vaccines available in Australia for the prevention of shingles:

  • Zostavax®- a live-attenuated vaccine
  • Shingrix®- an adjuvanted recombinant varicella zoster virus glycoprotein E (gE) subunit (non-live) vaccine

Zostavax®

Administration

Immunisation with Zostavax® requires a single dose of 0.65ml to be administered subcutaneously. It can be given to individuals who have previously been diagnosed with shingles, as well as co-administered with other vaccines on the NIP and influenza vaccines. ATAGI recommends an interval of 7 days between administering Zostavax® and COVID-19 vaccines.

Zostavax® is registered for use in those aged ≥ 50 years and is funded on the National Immunisation Program (NIP) for those aged 70 years (with a catch up program for those 71-79 years, ending October 2021).

Zostavax® is a live-attenuated vaccine and its use is contraindicated in immunocompromised individuals due to the risk of vaccine-related disease.

Efficacy

Zostavax® has been shown to reduce the incidence of shingles by approximately 50% and the incidence of PHN by 66%.

Evidence suggests that efficacy decreases with increasing age and immunogenicity declines rapidly by 5-10 years after vaccination.

Side effects

Zostavax® has been demonstrated to be safe and well tolerated. The most common side effects include injection site reactions and a localised varicella-like rash, commonly occurring in the first 72 hours.

Very rarely a non-localised VZV-like rash can occur 2-4 weeks following immunisation. Should this occur, medical attention is recommended for advice and management of symptoms which may include diagnostic testing and antiviral treatment. This event must also be reported to the relevant vaccine safety service (SAEFVIC in Victoria).

Contraindications and precautions

Zostavax® is live-attenuated vaccine and is therefore contraindicated in immunocompromised individuals. Immunosuppression may be caused by medical conditions or specific medications or therapies. The pre-immunisation screening of patients prior to administering Zostavax® is essential to avoid the risk of inadvertent immunisation in patients contraindicated to receive Zostavax® [please refer to Australian Immunisation Handbook: Table. Live shingles vaccine (Zostavax) screening for contraindications for more information].

If there is uncertainty about how severely a person is immunocompromised and whether it is safe for them to receive a vaccine, do not vaccinate them. Seek expert advice from their treating physician or an immunisation specialist.

The TGA has issued an alert regarding the use of Zostavax® in people with compromised immune function. Further information can be found at TGA: Safety advisory- risk of infection with a vaccine virus.

Inadvertent administration of Zostavax® in immunocompromised individuals

If an immunocompromised patient is inadvertently administered a dose of Zostavax®, prompt action is required. Medical review by an infectious diseases specialist or immunisation expert must be facilitated and the appropriate anti-viral therapy and monitoring commenced.

The error must also be reported to the relevant authority to ensure appropriate follow up and support can be provided. In Victoria, this service is SAEFVIC.

If the error occurs out of hours, seek specialist advice from the patient’s treating specialist or an infectious diseases specialist at your local tertiary hospital.

Shingrix®

Administration

Immunisation with Shingrix® requires a course of 2 doses of 0.5ml, administered 2-6 months apart. It is given intramuscularly.. ATAGI recommends a 7 day interval between the administration of COVID-19 vaccines and Shingrix, and prefers that FluadQuad and Shingrix are not co-administered on the same day.

Shingrix® is registered for use in adults aged ≥ 50 years. It is only available through private prescription and supplies are currently limited.

Shingrix is a non-live vaccine and as such can safely be administered to immunocompromised individuals.

Efficacy

Shingrix® is preferred over Zostavax® for the prevention of shingles due to a higher efficacy, particularly in the older population. In those aged ≥ 50 years, Shingrix provided 97% protection against shingles in immunocompetent individuals and 91% protection in those aged > 70 years.

Clinical trials have demonstrated high efficacy up to 4 years following vaccination with immunogenicity data indicating this is likely to persist beyond 10 years.

Side effects

Expected side effects of Shingrix® include injection site reactions, fatigue, myalgia, headaches and fever and last 1-3 days. These occur at slightly higher rates than following Zostavax®.

An additional 3-6 cases of Guillain Barre Syndrome (GBS) per million doses of Shingrix® administered have been estimated to occur.

Contraindications and precautions

Shingrix® should not be administered for the treatment of varicella, acute shingles disease or PHN.

Documentation

It is important that immunisation records are accurately maintained and reviewed prior to vaccine administration to avoid any dosing errors. Patient recall is not always reliable and as such reviewing an individual’s immunisation history is essential. From July 2021, the reporting of all NIP vaccines to the Australian Immunisation Register (AIR) is mandatory.

Resources

Authors: Nigel Crawford (Director, SAEFVIC, Murdoch Children’s Research Institute) and Georgina Lewis (Clinical manager, SAEFVIC, Murdoch Children’s Research Institute)

Reviewed by: Francesca Machingaifa (MVEC Education Nurse Coordinator) and Rachael McGuire (MVEC Education Nurse Coordinator)

Date: July 2021

Materials in this section are updated as new information and vaccines become available. The Melbourne Vaccine Education Centre (MVEC) staff regularly reviews materials for accuracy.

You should not consider the information in this site to be specific, professional medical advice for your personal health or for your family’s personal health. For medical concerns, including decisions about vaccinations, medications and other treatments, you should always consult a healthcare professional.