背景

Vaccine-associated enhanced disease (VAED) is a rare phenomenon where a person who has been vaccinated experiences A (usually) more severe clinical presentation of an infection than would normally be seen in an unvaccinated person. The mechanism for how VAED occurs complex and not clearly understood. Mechanisms may includebehavourAntibodies generated from vaccinationabnormal T-cell responses. With the exception of dengue vaccination, where use is restricted to minimie VAED risk (see below), vaccines that have been associated with VAED are no longer in use.

诊断

It can be difficult to distinguish between breakthrough disease (when disease occurs in a vaccinated individual because of inadequate vaccine protection) and VAED. To identify a case of VAED, it is necessary to have a clear understanding of the clinical presentation and usual course of the natural disease. VAED is identified by comparison to the natural disease; the clinical presentation of VAED is atypical, modified or more severe. Factors to be considered when assessing a possible case of VAED include:

  • expected background rates of disease
  • age
  • sex
  • time of symptom onset after vaccination
  • duration of disease
  • clinical course and progression of disease
  • any co-morbidities.

Various laboratory and clinical diagnostic parameters can be used to help assess the possibility of VAED, including detailed review of all cases of possible vaccine failure.

Associations

Vaccines that have been associated with the development of VAED include an inactivated respiratory syncytial virus (RSV) vaccine, an inactivated measles vaccine and a vaccine for dengue fever. (Note that the RSV and measles vaccines associated with VAED are not in use in Australia.)

VAED was observed in the 1960s during clinical trials for an inactivated whole-virus vaccine against RSV. In these trials, some children who had received the vaccine and then were later diagnosed with RSV infection developed more serious disease. As a result, this vaccine was never approved for general use.

People who received an inactivated measles vaccines in the 1960s were found to be more likely to develop an atypical form of measles disease if they were infected. This vaccine is no longer available, and the current measles-containing vaccines are not associated with the same adverse effects.

Dengvaxia, a live-attenuated recombinant dengue vaccine that is currently the only licensed dengue vaccine globally, has also been associated with VAED. If given to someone who has never had dengue infection, Dengvaxia can increase the risk of serious disease if the person is infected with dengue after vaccination. For this reason, Dengvaxia is only recommended in specific groups of people who have already had dengue infection, for prevention of subsequent, more serious secondary infection, within closely defined criteria.

Given the rare possibility of VAED, careful surveillance for potential VAED is an important part of both development of new vaccines, and post-licensure vaccine safety surveillance. 

对未来剂量的影响

All vaccines currently available through the 国家免疫计划 (NIP) are not linked to VAED.
COVID-19 vaccines are not linked to VAED.

Dengvaxia is registered by the Therapeutics Goods Administration (TGA), but is not currently marketed in Australia.

作者: Nigel Crawford (Director SAEFVIC, Murdoch Children’s Research Institute), Adele Harris (SAEFVIC Research Nurse, Murdoch Children’s Research Institute), Georgina Lewis (SAEFVIC Clinical Manager, Murdoch Children’s Research Institute), Julia Smith (RCH Immunisation Fellow) and Francesca Machingaifa (MVEC Education Nurse Coordinator)

审核人: 阿黛尔哈里斯 (SAEFVIC Research Nurse, Murdoch Children’s Research Institute), Ingrid Laemmle-Ruff (免疫接种 Consultant SAEFVIC, Murdoch Children’s Research Institute) 和 RachAel McGuire (MVEC 教育护士协调员, Murdoch Children’s Research Institute)

日期: April 2024

本章节内的材料将随着新信息的出现而进行更新。墨尔本疫苗教育中心(MVEC)职员定期审阅材料的准确性。

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