Journal Club

NCIRS holds weekly Journal Club forums where relevant and topical literature on all aspects of immunisation in Australia and overseas is reviewed by NCIRS staff. Peer-reviewed articles are critiqued and items that are considered "hot topics" are raised and discussed.

From time to time, NCIRS also hosts external guest speakers, including immunisation experts from Australia and overseas.

Summaries of these Journal Club presentations can be accessed via the menu, left, and are circulated to the NCIRS-AIP electronic discussion group.

• Current roster – February - June 2010 - PDF

Journal Club summaries – 2010

Pertussis disease burden in the household: how to protect young infants

de Greeff SC, Mooi FR, Westerhof A, et al
Clinical Infectious Diseases 2010;50(10):1339–45
Link to abstract http://www.ncbi.nlm.nih.gov/pubmed/20370464?dopt=Abstract

A strength of this study is the high number of identified household contacts who underwent laboratory diagnostic testing for pertussis (723 of 738, 98%), a figure much higher than many previous studies.

The results of this study are in agreement with many of the recently published pertussis source of infection studies which identify the mother as a prominent source of infection of infant pertussis cases. A point of difference of this study is the identification of siblings as being the most likely source of infection in this case. This finding concurs with a small number of Australian source of infection studies, including study populations of both hospitalised and non-hospitalised infant pertussis cases, which also found siblings to be a likely source of infection.

When considering the generalisability of these results, one should be mindful that the Dutch immunisation schedule was changed from a whole-cell vaccine (Dutch DTP-IPV-Hib) to an acellular vaccine in 2005 (Infanrix-IPV-Hib [GSK-Belgium] and later Pediacel [Sanofi PasteurMSD-Canada]). The results of this study demonstrated that children vaccinated with the whole cell vaccine were more likely to acquire pertussis infection than those vaccinated with the acellular vaccine, which may explain the higher prominence of siblings as a source of infection in this study.

These results support the rationale behind a ‘cocooning’ strategy – the immunisation of household contacts of newborn infants – to protect this vulnerable group against pertussis.

Presented by Kerrie Wiley, Research Assistant, NCIRS

A decline in varicella but an uncertain impact on zoster following varicella vaccination in Victoria, Australia

Carville KS, Riddell MA, Kelly HA
Vaccine 2010;28(13):2532-2538
Link to abstract: http://www.ncbi.nlm.nih.gov/pubmed/20117265?dopt=Abstract

In Australia, the varicella vaccine (VV) has been available on the private market since 2000 and was placed on the National Immunisation Program (NIP) in November 2005 for infants aged 18 months with a school-based catch-up campaign for 12–13 year olds. The aim of this study was to evaluate the impact of this program on hospitalisations and calls to the Melbourne Medical Deputising Service (MMDS) for VZV disease – both primary varicella and herpes zoster. This study reports on the yearly trends in varicella and zoster-related hospitalisations in Victoria, Australia, and compares hospitalisation rates and patient characteristics across three periods of vaccine availability.

This study shows that the hospitalisation rates for any diagnosis of varicella and for a principal diagnosis of varicella declined after placement of VV on the NIP, with principal varicella hospitalisations declining from 4.0 per 100,000 (95% CI: 3.8–4.2) in the period prior to vaccine availability and 4.2 per 100,000 (95% CI: 4.0–4.4) during availability on the private market to 3.1 per 100,000 (95% CI: 2.6–3.7) in the 2 years since funding on the NIP. The decline has been predominately seen in children under 5 years of age with the decline emulated in the MMDS data. After NIP listing, a decline in hospitalisations was also seen in adults aged 20–49 years, with a 39% decline between private and public vaccine periods. This decline has resulted in a significant increase in the median age of hospitalisations containing coding for varicella.

This study also shows that the hospitalisation rates for a principal diagnosis of zoster have increased an average of 5% per year (95% CI: 3%–6%) between 1998 and 2007 with a significant increase between private and public VV availability in hospitalisations among those aged 80 and over. However, these results are limited by the ecological nature of the study and that multiple admissions for the same individual are likely in the elderly and may be increasing with an ageing population. This may also be reflected in the significant increase in median age in zoster hospitalisations from 71 years (IQR 54–81) prior to vaccine availability, to 73 years (IQR 58–81) during VV private availability to 76 years (IQR 61–83) during the VV NIP program period.


Presented by Anita Heywood, Research Assistant, NCIRS

Thrombocytopenic purpura after measles-mumps-rubella vaccination: a systematic review of the literature and guidance for management

Mantadakis E, Farmaki E, Buchanan GR
Journal of Pediatrics 2010;156(4):623-8.
Link to abstract http://www.ncbi.nlm.nih.gov/pubmed/20097358?dopt=Abstract

Immune thrombocytopenia purpura (ITP) is an autoimmune disorder with bleeding tendency. The measles-mumps-rubella (MMR) vaccine was reported to be likely associated with benign thrombocytopenia purpura (Demicheli et al., 2005). However, there was no systematic review looking at the causal relationship between ITP and MMR vaccine. Mantadakis and colleagues did a systematic review based on 12 studies and assessed the incidence of ITP after MMR vaccination compared with natural measles and rubella, and the clinical course, outcome and recurrence. They concluded that MMR-associated ITP is rare and benign. The findings of this systematic review are valuable for clinical practice and policy making around MMR vaccination.
Reference:
Demicheli V, Jefferson T, Rivetti A, Price D. Vaccines for measles, mumps and rubella in children. Cochrane Database of Systematic Reviews 2005;(4):CD004407

Presented by Dr Kevin Yin, Research Assistant, NCIRS