其 他 安 全 警 示
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| Australia: Safety advisory: Careful assessment and screening for immunocompromise essential before administration of Zostavax (English only) |
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The Therapeutic Goods Administration (TGA) announces that it has published previous safety advice about avoiding the use of Zostavax vaccine in immunocompromised patients but continues to receive reports of such cases. This is a reminder that careful assessment and screening for immunocompromise is essential before administration of Zostavax, with resources to assist in the process.
All patients for whom Zostavax is considered should be assessed for immunocompromise prior to vaccination. Do not administer Zostavax if the immune status of the patient is unclear. Zostavax is contraindicated in patients with current or recent severe immunocompromising conditions from either a primary or acquired medical condition or medical treatment. Fatalities due to disseminated disease with vaccine (Oka) strain varicella zoster virus (VZV) have followed administration of Zostavax to immunocompromised patients. The risk of disseminated VZV infection with vaccine (Oka) strain increases with the degree of immunosuppression.
Assessing immunocompromise can be complex. A screening checklist to identify patient contraindications prior to vaccination is available in the Australian Immunisation Handbook. Assessment before vaccination can include consulting a medical specialist and screening for pre-existing antibody to VZV. Defer vaccination until advice and results have been obtained.
An immunosuppressed patient who has been inadvertently vaccinated with Zostavax should be informed of the potential for developing disseminated VZV infection. Any patient who experiences a disseminated vesicular (chickenpox-like) rash 2 to 4 weeks after vaccine administration, or who feels unwell or has a fever, should seek medical attention immediately and tell the doctor they have received Zostavax.
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 or infectious diseases physician.
- where appropriate, initiate appropriate empiric antiviral therapy while awaiting test results
- where feasible, cease immunosuppression in consultation with their treating specialist.
The TGA has received three reports of fatal cases of disseminated VZV infection involving the vaccine (Oka) strain following Zostavax administration. Two of the three deaths arose from medication errors involving the administration of Zostavax to immunocompromised patients. The third death was in an immunocompetent patient.
The TGA has published safety advisories about avoiding the use of Zostavax in people who are immunocompromised and has required the sponsor to undertake several risk mitigation activities. Despite these activities, the TGA has received five reports of Zostavax administration in immunocompromised patients since 1 Jul 2021. In all five cases Zostavax was given to patients were subsequently identified to be receiving concurrent immunosuppressive therapies. Neither disseminated VZV infection or death have been reported in any of these cases. Expert advice provided by the Advisory Committee on Vaccines on 1 Dec 2021 acknowledged the main area of difficulty was not likely a lack of awareness that Zostavax should not be given to immunocompromised patients, but rather the complexity of around the assessment and definition of 'immunocompromise'.
Please refer to the following website in TGA for details:
http://www.tga.gov.au/alert/zostavax
In Hong Kong, Zostavax For Vaccine (HK-55419) is a pharmaceutical product registered by Merck Sharp & Dohme (Asia) Ltd. The product 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 since 8 Mar 2017, with the latest update posted on 2 Jun 2021. Letters to inform local healthcare professionals were issued by the DH on 2 Jun 2021. In Dec 2021, the Registration Committee of the Pharmacy and Poisons Board discussed the matter and decided to keep vigilant on any update from other health authorities on the matter. The current local product insert of Zostavax includes information on “Do not administer Zostavax to individuals who are immunodeficient or immunosuppressed due to disease or therapy, as serious or fatal disseminated vaccine strain varicella-zoster virus disease may occur.” The DH will remain vigilant on safety update of the product issued by other overseas drug regulatory authorities.
Ends/Thursday, Feb 17, 2022
Issued at HKT 15:00
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