Zostavax vaccine - risk of infection in people with compromised immune function

The Therapeutic Goods Administration (TGA) has previously advised that Zostavax should not be used in people with compromised immune function, as it is associated with a risk of mild to serious complications (including death) from infection with the vaccine virus.

Consumers and health professionals are advised that the TGA has received a report of a new case involving this adverse event in a patient on low doses of immunosuppressive medicine.

The patient, who at the time of vaccination was taking hydroxychloroquine and a low dose of prednisolone to treat arthritis, died 3 weeks after receiving Zostavax.

The TGA investigation found that Zostavax was used in line with existing recommendations. However, it is important for health professionals to be mindful of the potential for this very rare adverse event.

Zostavax is a live, attenuated varicella-zoster virus vaccine that is used to prevent shingles in patients aged 50 years and older and prevention/treatment of nerve pain associated with the virus in patients aged 60 years and older.

Zostavax is included on the National Immunisation Program for people aged 70 to 79 years.

Information for consumers

If you are concerned about whether you or someone you provide care for can receive Zostavax, please speak to your health professional.

The most common adverse event following Zostavax are injection site reactions. Serious reactions, such as the disseminated varicella-zoster virus infection reported in this advisory, are very rare.

If you become unwell after vaccination, you should seek medical attention and tell your doctor that you have recently received Zostavax.

Seek immediate medical attention if you:

• develop a chickenpox-like rash within 2 to 4 weeks of vaccine administration
• feel unwell
• develop a fever.

Information for health professionals

Health professionals are reminded that, on rare occasions, disseminated varicella-zoster virus (Oka vaccine strain) infection can occur in patients following administration of Zostavax vaccine. This case has demonstrated that this can occur in patients who are on low dose immunomodulation and demonstrates the importance of careful prescreening and a risk-based assessment prior to Zostavax administration. If necessary, this could include medical specialist consultation and potentially screening for pre-existing antibody to varicella-zoster virus. The Australian Immunisation Handbook contains the current guidance on screening.

If a recent Zostavax recipient is suspected of having disseminated varicella-zoster virus infection the health professional should:

• conduct appropriate diagnostic testing early
• where appropriate, initiate acyclovir empirically while awaiting test results
• where feasible, cease immunosuppression.

The Australian Immunisation Handbook contains information about Zostavax administration in special populations, including patients who are immunocompromised or have medical conditions that place them at risk of immunocompromise. Additionally, information can also be obtained from the National Centre for Immunisation Research and Surveillance.

The TGA convened an expert panel consisting of infectious disease physicians (with expertise in vaccines and vaccine safety), a rheumatologist and a respiratory physician to review the role of Zostavax vaccine in the death of the patient. The Panel reviewed the case details and the available published literature using a World Health Organization causality assessment framework.

The Panel noted that the vaccine was administered consistent with existing recommendations, with the dose of hydroxychloroquine and prednisolone below the level expected to cause significant immunosuppression. The Panel concluded that the clinical findings were consistent with a causal association between Zostavax and fatal (vaccine-related) varicella-zoster virus infection.

The panel also noted that a high index of suspicion, early diagnostic testing, prompt empirical antiviral therapy, and where feasible, cessation of immunomodulatory therapy, are all important in such cases.

How this case adds to the safety information about Zostavax

This case draws attention to the potential for the rare event of disseminated vaccine-related varicella-zoster virus infection in patients on low doses of immunosuppressive medication, occurring typically 2 to 4 weeks after Zostavax vaccination.

Disseminated varicella-zoster virus infection is potentially life-threatening and suspicion should prompt appropriate diagnostic testing, initiation of empirical aciclovir treatment while awaiting test results and, where possible, cessation of immunosuppression.

Patients should be advised to seek medical attention if they become unwell after receiving Zostavax, and to ensure that they mention their vaccination history to their treating health professional.

Reporting problems

Consumers and health professionals are encouraged to report problems with medicines or vaccines. Your report will contribute to the TGA's monitoring of these products.

The TGA cannot give advice about an individual's medical condition. You are strongly encouraged to talk with a health professional if you are concerned about a possible adverse event associated with a medicine or vaccine.