The Therapeutic Goods Administration (TGA) announces that following a third report of fatal disseminated vaccine strain varicella-zoster virus infection following Zostavax administration, it is reminding health professionals that Zostavax should not be used in people with compromised immune function. Healthcare professionals should carefully assess patients for potentially immunocompromising conditions.
The TGA is working with the sponsor of Zostavax to strengthen advice in the Product Information, with particular emphasis on use in immunocompromised patients and the risk of disseminated varicella-zoster virus infection post-vaccination. In Australia, Zostavax is a live, attenuated varicella-zoster virus vaccine that is used to prevent shingles in patients aged 50 years and older and prevention of nerve pain associated with the virus in patients aged 60 years and older. The TGA issued safety advisories in March 2017 and July 2020 following two previous reports of fatal disseminated vaccine strain varicella-zoster virus infection.
The TGA has received a report of a new case involving this adverse event in a patient on immunosuppressive medicine. The patient, who at the time of vaccination was taking prednisolone (steroid medication) and had also recently been taking checkpoint inhibitors (medication that modulates the immune system), died a few weeks after receiving Zostavax. The risk of disseminated varicella zoster virus infection with the vaccine strain increases with the degree of immunosuppression.
In Australia, Zostavax is included on the National Immunisation Program (NIP) for people aged 70 to 79 years. More than a million eligible Australians have been administered Zostavax since the NIP started in 2016. Zostavax contains live, attenuated varicella-zoster virus, which is the virus that causes chickenpox and shingles. Infection with varicella-zoster virus can be localised to an area of skin, but can also take a more serious, generalised form that affects a wider area of the body. Widespread infection is called disseminated varicella zoster virus infection. Zostavax should not be used in people whose immune system is weakened by certain medical conditions or medicines because of the risk of disseminated varicella zoster virus infection with the vaccine virus, which can cause serious illness and death.
Consumers are advised that, if you are concerned about whether you or someone you provide care for can receive Zostavax, please speak to your healthcare professional. You should tell your doctor of all active medical problems and current medications before having the Zostavax vaccine. If your immune system is compromised by any medical problems or medications then it may not be safe for you to have the Zostavax vaccine. The most common adverse events following Zostavax are reactions at the site of injection, such as redness, pain and swelling. 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 two to four weeks of vaccine administration, feel unwell, or develop a fever.
Health professionals are reminded that, rarely, disseminated varicella-zoster virus (Oka vaccine strain) infection can occur in patients following administration of Zostavax vaccine. Although this adverse event can occur in immunocompetent patients, the risk increases with the degree of immunosuppression. The new case demonstrates the importance of careful pre-screening and a risk-based assessment prior to the administration of Zostavax. Do not administer Zostavax if the immune status of the patient is unclear. If appropriate, pre-screening could include medical specialist consultation and potentially screening for pre-existing antibody to varicella-zoster virus. If inadvertent vaccination in an immunosuppressed patient has occurred, the patient should be advised regarding the potential for disseminated varicella zoster virus infection and the need to seek medical advice should symptoms suggestive of this occur, so that they can be considered for pre-emptive antiviral therapy.
Healthcare professionals should advise patients 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. If a recent Zostavax recipient is suspected of having disseminated varicella-zoster virus infection the health professional should conduct appropriate diagnostic testing early in consultation with a clinical microbiologist; initiate appropriate empiric antiviral therapy while awaiting test results; and where feasible, cease immunosuppression in consultation with the patient’s treating specialist.
This case draws attention to the potential for the rare event of disseminated vaccine-related varicella-zoster virus infection, occurring typically two to four weeks after Zostavax vaccination. This is the third fatal report received by the TGA of fatal disseminated vaccine strain varicella-zoster virus infection following Zostavax administration. Two reports have been in immunocompromised patients, and one in an immunocompetent patient.
The TGA convened an expert panel consisting of infectious disease physicians (with expertise in vaccines and vaccine safety), an oncologist 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 patient was contraindicated to receive the vaccine, due to his severe immunocompromise secondary to metastatic melanoma and high dose steroids. 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.
Please refer to the following website in TGA for details:
http://www.tga.gov.au/alert/zostavax-vaccine-1
In Hong Kong, Zostavax For Vaccine (HK-55419) is a pharmaceutical product registered by Merck Sharp & Dohme (Asia) Ltd, and is a prescription-only medicine. So far, the Department of Health (DH) has received 6 cases of adverse events following immunisation with Zostavax, but none of them involved death. Related news was previously issued by TGA, and was posted on the Drug Office website on 8 Mar 2017 and 7 Jul 2020. The current local product insert includes immunosuppressed and immunodeficient individuals as contraindications. The DH will remain vigilant on safety update of the product issued by other overseas drug regulatory authorities.
Ends/ Wednesday, December 23, 2020
Issued at HKT 17:00
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