The MMR Controversy: Highly educated parents were more likely to stop their children being vaccinated
In the latest of our podcasts supporting the Royal Economic Society Conference 2008 Romesh Vaitilingam talks to Dan Anderberg about some socio-economic analysis of the effects of the MMR controversy.
Highly educated parents responded more strongly to the controversial study linking the measles, mumps and rubella (MMR) vaccine to the development of autism in children. That is the central finding of new research by Professor Dan Anderberg and colleagues presented at the Royal Economic Society’s 2008 annual conference.
Whats more, the study finds, these parents were less likely to have their children vaccinated against other diseases after the controversy, not just MMR. Since there was never any suspicion of doubt about other vaccines, this may have put the health of their children at risk.
The publication of medical research linking the MMR vaccine to autism in The Lancet in February 1998 sparked a decade-long controversy about the triple jab. Following the initial publication, the uptake rate of the MMR vaccine dropped from 92% in 1997/98 to 80% in 2003/04.
The new report examines how the response to the MMR controversy varied between parents with different levels of education. It reveals that:
- Before 1998, highly educated parents were up to 8% more likely to take up the MMR vaccine than parents with lower education.
- By 2002, this gap had not only closed; it had actually been reversed, with highly educated parents being 2-3% less likely to accept the MMR vaccine.
- Most of the relative decline in the MMR uptake by highly educated parents occurred soon after the controversy broke when the media coverage was still relatively low.
- After the increased media attention in 2001 and 2002, there were no discernible differences in trends across educational groups.
- The controversy also appears to have had effects on the uptake of other childhood vaccines: after 1998, highly educated parents also reduced their relative uptake of other non-controversial childhood vaccines.
The original research publication described a set of bowel symptoms and suggested a link to autism. The study included eight children whose parents said they had developed normally until they were given the MMR, and then had begun to regress. Dr Andrew Wakefield, the lead researcher suggested that children should be given the three vaccines separately rather than the combined MMR jab.
In the following years, a substantial body of research failed to verify any link between the vaccine and autism, and successive research reviews concluded that the vaccine was safe. The controversy nevertheless led many parents to worry, and the MMR uptake rate fell far below the 95% immunity rate required to stop measles from being able to spread.
The new report uses data on the uptake of immunisations collected at the Health Authority area level, which the authors combine with population characteristics from the Health Survey for England. The authors also use data from the Millennium Cohort Survey, which contains information on 8,000 English children due to obtain the MMR at the height of the controversy.
The finding that more educated parents had, at the peak of the controversy, a lower uptake rate is remarkable: generally higher educated parents are more likely to vaccinate their children.
The relative decline in uptake by highly educated parents also potentially has wider significance. Generally speaking, individuals with more education have better health. This is possibly because they are better informed about how to achieve better health outcomes. The finding that highly educated parents were the first to react to the information that the MMR had potential side effects is consistent with this hypothesis.
More puzzling is the finding that highly educated parents also reduced their uptake of other non-controversial childhood vaccines. One explanation for this is that they reacted to the overload theory, which states that too many vaccines, and multi-component vaccines in particular, could potentially be harmful to infants, a theory that was expressed at the time by Dr Wakefield and some of his colleagues.
Notes for editors: Health and Knowledge: The UK Measles, Mumps and Rubella Controversy by Dan Anderberg, Arnaud Chevalier and Jonathan Wadsworth was presented at the Royal Economic Societys annual conference at the University of Warwick, 17-19 March 2008.
The authors are at Royal Holloway, University of London. Arnaud Chevalier and Jonathan Wadsworth are also members of the Centre for Economic Performance at the London School of Economics.
For further information: contact Dan Anderberg on 01784-414082 (email: Dan.Anderberg@rhul.ac.uk); Arnaud Chevalier on 01784-414971 (email: firstname.lastname@example.org); Jonathan Wadsworth on 01784-443464 (email: email@example.com); or Romesh Vaitilingam on 07768-661095 (email: firstname.lastname@example.org).