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The assessment of rare adverse events following vaccination may not be possible within a single country due to an insufficiently large denominator population. In 2008 a European consortium (VAESCO) was funded to perform collaborative vaccine safety studies. To help assess the feasibility of multi-country collaboration England and Denmark, who have established vaccine safety research infrastructures, undertook to work to a common protocol and share results and data to estimate the risk of a known true adverse event, thrombocytopenic purpura (TP) following measles-mumps-rubella (MMR) vaccination. TP is a known rare reaction to MMR and therefore provided an opportunity to assess whether two countries would produce similar results when working collaboratively. Despite some initial problems with ensuring data were comparable, the two countries gave very similar estimates of the relative incidence in the 6 weeks after vaccination and a pooled relative incidence estimate of 2.13 (95% confidence interval 1.55-2.94) and attributable risk of 1 in 50,000 doses. Both countries used hospital admissions for TP and the analysis was performed using the self controlled case series method which is particularly suited to collaborative studies because of its implicit control for individual level confounding. The study therefore shows the potential for vaccine safety collaborations across Europe to detect true associations through use of common protocols and sharing of results or data., (Copyright © 2011 Brighton Collaboration. Published by Elsevier Ltd.. All rights reserved.)

We analyzed data from hospital admissions and enhanced mumps surveillance to assess mumps complications during the largest mumps outbreak in England and Wales, 2004-2005, and their association with mumps vaccination. When compared with nonoutbreak periods, the outbreak was associated with a clear increase in hospitalized patients with orchitis, meningitis, and pancreatitis. Routine mumps surveillance and hospital data showed that 6.1% of estimated mumps patients were hospitalized, 4.4% had orchitis, 0.35% meningitis, and 0.33% pancreatitis. Enhanced surveillance data showed 2.9% of mumps patients were hospitalized, 6.1% had orchitis, 0.3% had meningitis, and 0.25% had pancreatitis. Risk was reduced for hospitalization (odds ratio [OR] 0.54, 95% confidence interval [CI] 0.43-0.68), mumps orchitis (OR 0.72, 95% CI 0.56-0.93) and mumps meningitis (OR 0.28, 95% CI 0.14-0.56) when patient had received 1 dose of measles, mumps, and rubella vaccine. The protective effect of vaccination on disease severity is critical in assessing the total effects of current and future mumps control strategies.

Concern exists about measles, mumps and rubella (MMR) vaccine in egg-allergic children, although this has been shown to be safe. Guidelines from the Royal College of Paediatrics and Child Health (RCPCH) and British Society of Allergy and Clinical Immunology (BSACI) suggesting which children should be referred to hospital for MMR, were published in 2000. We audited referrals to hospital for MMR against these guidelines. One hundred and ten children were referred for MMR to Birmingham Heartlands Hospital (2002-2004) and Alder Hey Children's Hospital (2006-2009). Eighty-two (75%) children did not meet the published criteria. Only 13 children (12%) had severe egg allergy. The first dose of MMR vaccine was delayed by >30 days in 81% of children. All children were given MMR, none had a significant reaction. Children with egg allergy do not need to be given MMR in hospital, but MMR is often delayed by unnecessary hospital referral. New BSACI guidelines encouraging MMR vaccination of egg-allergic children in primary care need to be disseminated.

Background: In industrialized countries vaccination coverage remains suboptimal, partly because of perception of an increased risk of asthma. Epidemiologic studies of the association between childhood vaccinations and asthma have provided conflicting results, possibly for methodologic reasons such as unreliable vaccination data, biased reporting, and reverse causation. A recent review stressed the need for additional, adequately controlled large-scale studies., Objective: Our goal was to determine if routine childhood vaccination against pertussis was associated with subsequent development of childhood wheezing disorders and asthma in a large population-based cohort study., Methods: In 6811 children from the general population born between 1993 and 1997 in Leicestershire, United Kingdom, respiratory symptom data from repeated questionnaire surveys up to 2003 were linked to independently collected vaccination data from the National Health Service database. We compared incident wheeze and asthma between children of different vaccination status (complete, partial, and no vaccination against pertussis) by computing hazard ratios. Analyses were based on 6048 children, 23 201 person-years of follow-up, and 2426 cases of new-onset wheeze., Results: There was no evidence for an increased risk of wheeze or asthma in children vaccinated against pertussis compared with nonvaccinated children. Adjusted hazard ratios comparing fully and partially vaccinated with nonvaccinated children were close to one for both incident wheeze and asthma., Conclusion: This study provides no evidence of an association between vaccination against pertussis in infancy and an increased risk of later wheeze or asthma and does not support claims that vaccination against pertussis might significantly increase the risk of childhood asthma.

Measles-mumps-rubella (MMR) vaccines containing the Urabe strain of mumps were withdrawn in the United Kingdom in 1992 following demonstration of an increased risk of aseptic meningitis 15-35 days after vaccination. Following introduction of a replacement MMR vaccine (Priorix; GlaxoSmithKline, London, United Kingdom) in 1998, active surveillance of aseptic meningitis and convulsion was established to evaluate the risk associated with the new vaccine. No laboratory-confirmed cases of mumps meningitis were detected among children aged 12-23 months after administration of 1.6 million doses of Priorix (upper 95% confidence limit of risk: 1:437,000) in England and Wales. The upper 95% confidence limit excluded the risk found for mumps meningitis with Urabe vaccines (1:143,000 doses). No cases of aseptic meningitis were detected among children aged 12-23 months, who had received over 99,000 doses of Priorix (upper 95% confidence limit of risk: 1:27,000), in a regional database of hospital-admitted cases. This compares with an observed risk of 1:12,400 for Urabe vaccines. An elevated relative incidence of convulsion was found in the 6- to 11-day period after receipt of Priorix (relative incidence = 6.26, 95% confidence interval: 3.85, 10.18)-consistent with the known effects of the measles component of MMR vaccine-but not in the 15- to 35-day period (relative incidence = 1.48, 95% confidence interval: 0.88, 2.50) as occurred with Urabe-containing vaccines. This study demonstrates the power of active postmarketing surveillance to identify or exclude events too rare to be detected in prelicensure trials.

Graphs have been used in attempts to show a relationship between the measles, mumps and rubella virus (MMR) vaccine and autism. We examine the topic of graphical representation of data in general, and one of these graphs in particular: the one that appeared in a 1999 letter to The Lancet. That graph combined data from England and from California, USA. The author alleged that this graph illustrated a rise in autism rates linked to the use of the MMR vaccine. By examining the presentation closely, we are able to show how this graph misrepresented the data used. We give advice for both authors and publishers in the use of such graphical treatments of data.

Background: MMR vaccine has been reported to cause gait disturbance, and this possible association has been claimed to support the MMR-causes-autism theory., Aims: To determine whether any association between gait disturbance and MMR vaccination exceeds the age related background rate of gait disturbance, using record linkage and self control case series analyses., Methods: MMR vaccination records were linked to hospital admission and general practitioner attendance data. An increased rate of gait problems with onset in various intervals in the 60 day period after MMR vaccination was looked for in children aged 12 to <24 months., Results: No evidence of an increased rate of hospital admission or general practice consultations for gait disturbance was found in the putative post-vaccination risk periods., Conclusions: This study provides no evidence for a causal association between MMR and gait disturbance.

Background: The uptake of the combined measles, mumps and rubella immunisation (MMR) in Britain has fallen since 1998, when a link was hypothesised with the development of bowel disorders and childhood autism. Despite reassurances about the safety of MMR, uptake levels remain lower than optimal. We need to understand what influences parents' decisions on whether to accept MMR or not so that health professionals can provide a service responsive to their needs., Aim: To investigate what influences parents' decisions on whether to accept or refuse the primary MMR immunisation and the impact of the recent controversy over its safety., Design: Qualitative study using focus group discussions., Setting: Forty-eight parents, whose youngest child was between 14 months and three years old, attended groups at community halls in six localities in Avon and Gloucestershire., Methods: Purposive sampling strategy was used to include parents from a variety of socioeconomic backgrounds. Three groups comprised parents who had accepted MMR and three groups comprised parents who had refused MMR. Data analysis used modified grounded theory techniques incorporating the constant comparative method., Results: All parents felt that the decision about MMR was difficult and stressful, and experienced unwelcome pressure from health professionals to comply. Parents were not convinced by Department of Health reassurances that MMR was the safest and best option for their children and many had accepted MMR unwillingly. Four key factors influenced parents' decisions: (a) beliefs about the risks and benefits of MMR compared with contracting the diseases, (b) information from the media and other sources about the safety of MMR, (c) confidence and trust in the advice of health professionals and attitudes towards compliance with this advice, and (d) views on the importance of individual choice within Government policy on immunisation., Conclusions: Parents wanted up-to-date information about the risks and benefits of MMR to be available in advance of their immunisation appointment. Many parents did not have confidence in the recommendations of health professionals because they were aware that GPs needed to reach immunisation targets. Most parents would, however, welcome more open discussion about immunisation with health professionals.