Elsevier

Vaccine

Volume 24, Issue 20, 15 May 2006, Pages 4321-4327
Vaccine

‘Combined vaccines are like a sudden onslaught to the body's immune system’: Parental concerns about vaccine ‘overload’ and ‘immune-vulnerability’

https://doi.org/10.1016/j.vaccine.2006.03.003Get rights and content

Abstract

The recent controversy surrounding the safety of the measles, mumps, and rubella vaccine (MMR) has heightened parents’ concerns about the safety of vaccines, and led some to believe that giving vaccines in a combined form may ‘overload’ children's immune systems. However, to date no studies have been published examining how British parents conceptualise the notion of ‘immune-overload’ or how they relate this concept to their own children. Eighteen focus groups were conducted with parents between November 2002 and March 2003. The literature on vaccine decision-making suggests that parents base their immunisation decisions on two key risks: those posed by the diseases, and those associated with the vaccines aimed at preventing those diseases. Our study suggested that for some parents a third factor plays an important role, namely their assessment of the ability of their child's immune system to ‘cope’ with the challenge of combined vaccines, or to fight the disease. We conclude that although there is no scientific evidence that supports parents’ fears about combined vaccines causing ‘immune-overload’, policy makers need to recognise these concerns if they are to successfully persuade parents that combined vaccines are safe.

Introduction

Since its inception in the late 19th Century, immunisation has contributed to the decline and control of many once-common infectious diseases. The paradox of this success is that, as parents have become have less familiar with these diseases, they have become more questioning about the safety and necessity of immunisation. The most recent example of this is the controversy surrounding the safety of the MMR vaccine precipitated by the publication of a case series of 12 children which raised the possibility of a link between the MMR vaccine, autism, and inflammatory bowel disease [1]. At a press conference on the day of publication one of the authors, Dr. Andrew Wakefield, suggested that there might be a case for splitting the MMR vaccine into its three separate component parts, each given a year apart. Although Wakefield's findings have neither been replicated [2], nor supported by the vast majority of studies, [3], [4], [5], [6], [7] his claims led many parents to decide to withhold or postpone MMR vaccination for their child.

In recognition of the growing public concern about the safety of the MMR vaccine, several studies have explored parents’ decision-making about MMR. Evans and colleagues suggest that parents conduct an informal risk-benefit analysis and that, for some parents, it is easier to live with the risk of their child naturally contracting a disease than ‘causing’ their child damage through vaccination [8]. This finding is consistent with earlier work on omission bias [9], [10] which suggested people feel more responsible for a child's death if it is the result of vaccination (commission) than from contracting a vaccine-preventable disease (omission). Another recent study found that parents who consider that diseases pose a threat to their child's health and who consider immunisation to be safe and effective are more likely to have their children immunised. In contrast, parents who consider that the diseases pose little or no threat to their child's health, and who consider immunisation to be ineffectual or to pose a risk to their child, are less likely to do so [11]. Further qualitative research has suggested that there are some potentially serious misunderstandings and gaps in parents’ knowledge about vaccine-preventable diseases, which generally led to a diminished sense of urgency or need for vaccination [12]. Raithatha and colleagues have suggested that, in weighing up the risks of vaccines against the risks of disease, parents consider the immunisation process and their trust in government and health professionals. Raithatha et al. warn that it is vital not to assume that parents who currently immunise will continue to do so, and suggest the MMR vaccine scare may have triggered a wider reappraisal of vaccine risk [13].

Although the vast majority of parents continue to have their children vaccinated, there has always been a minority of people opposed to vaccination. Indeed, concerns about the safety of vaccines pre-date the publication of Wakefield et al.'s (1998) paper, and concerns over vaccine safety are neither confined to the United Kingdom, nor limited to the MMR debate. For example, the controversy surrounding the safety of the pertussis vaccine in the 1970s led large numbers of parents to refuse it, resulting in a fall in vaccine coverage, several epidemics, and many fatalities. In Scotland the epidemics accounted for an estimated 100,000 notifications and up to 75 deaths [14]. Nicoll et al. suggest a similar picture in England and Wales, estimating over 300,000 notifications and at least 70 deaths [15]. One of the first qualitative studies to investigate British mothers’ experiences of childhood immunisation following the pertussis controversy found that problems arising from transport and time-constraints were not the only reasons to account for why children had missed appointments. They suggested that immunisation behaviours were influenced by attitudes towards, and knowledge of, infant immunisation [16]. A study conducted in the United States of America explored parents’ perceptions of vaccines and found that parents perceive vaccines to be only partly effective [17]. Similarly, an Australian study found that some parents opted not to immunise because they were concerned about the unknown, long-term side-effects of vaccines and believed that vaccines may place stress on the immune system rather than strengthening it [18]. Concerns about vaccine safety are not just confined to industrial countries. For instance, rumours about alleged adverse health effects associated with oral polio vaccine in Nigeria contributed to a temporary reduction in uptake [19].

There is no scientific evidence that supports parents’ fears about combined vaccines causing immune overload. Nevertheless, in order to allay parents’ fears Miller and colleagues sought clinical evidence to examine whether the MMR vaccine was associated with an increased susceptibility to infection requiring hospitalisation in the post-vaccination period [20]. Using computerised discharge records they identified 395 children who were admitted to hospital over a 4-year period with a bacterial infection within a 12-week period post-MMR vaccination. No increased risk of infection was found post-MMR vaccination and they concluded that the MMR vaccine does not impair the ability to respond to the immune challenge of infection. Although Miller's study may have allayed some parents’ fears, there is still little research exploring how parents conceptualise putative MMR-associated risks to their children's health, nor how they conceptualise the notion of immune-overload. Without understanding these issues it is difficult to ascertain whether the current reappraisal of vaccine risk that Raithatha et al. highlight is, as they suggest, a consequence of the recent MMR debate, whether it is part of a wider sense among parents that children are becoming over-immunised against diseases that no longer pose a significant threat to their children's health, or whether it is, as Lupton suggests, related to the increasing media focus on the immune system in Western culture [21]. Here we report on a qualitative study which explores parents’ concerns about immune overload and examines how parents relate this concept to their own children's health and vaccine decision-making.

Section snippets

Methods

Eighteen focus groups were conducted between November 2002 and March 2003. This method was selected because it offered considerable scope for participants to set the agenda and develop discussion around topics important to them [22]. The 72 participants were purposively selected to ensure the maximum variation possible [23]. Participants were from a range of ages, socio-economic circumstances, and family circumstances, including first-time mothers, more experienced mothers, single fathers, and

The findings

For many parents the controversy surrounding the MMR vaccine raised many questions. Two that were of particular concern were: whether children's immune systems are mature enough to cope with receiving several antigens in one vaccine, and whether some children's immune systems are less able to cope with the challenge of vaccination and more prone to long-term damage from combined vaccines. These are considered in turn.

Discussion

The aim of this focus group study was to conduct an in-depth exploration of parents’ beliefs and concerns about childhood immunisation. The exploratory nature of the inquiry predisposed the study towards the use of qualitative methods that are particularly useful when the aim is to gain an ‘in-depth understanding’, rather than ‘overall picture’, of a topic. The findings from this study offer original insights into parents’ perceptions about childhood immunisation and immunisation behaviours

Conclusion

As the Childhood Immunisation Programme has developed in Britain over the past century, the number of vaccines included has increased. For example, in the 1900s a child might only receive the smallpox vaccine, whereas by the 1950s children would have been offered five vaccines (diphtheria, pertussis, tetanus, polio, and smallpox). Today the programme offers protection against nine diseases (diphtheria, pertussis, tetanus, polio, haemophilus influenza type b, meningocococcal infection, measles,

Acknowledgements

We would like to thank all the parents who kindly agreed to take part in the study and the gatekeepers who facilitated contact with particular groups of parents. Thanks are also due to Professor Sally Macintyre and to the referees for their comments. This study was funded under a PhD studentship from the Medical Research Council. The funding body had no role in the design, collection, analysis or interpretation of this study. Mark Petticrew is funded by the Chief Scientist Office of the

References (29)

  • I. Ritov et al.

    Reluctance to vaccinate: omission bias and ambiguity

    J Behav Decision Making

    (1990)
  • D.A. Asch et al.

    Omission bias and pertussis vaccination

    Med Decision Making

    (1994)
  • M.S. Smailbegovic et al.

    Why do parents decide against immunization? The effect of health beliefs and health professionals

    Child: Care, Health and Development

    (2003)
  • Hilton S, Hunt K, Petticrew M. Gaps in parental understandings and experiences of vaccine-preventable diseases. A...
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