Media dents confidence in MMR vaccineBMJ 1998; 316 doi: https://doi.org/10.1136/bmj.316.7130.561 (Published 14 February 1998) Cite this as: BMJ 1998;316:561
- Norman Begg, consultant epidemiologist,
- Mary Ramsay, consultant epidemiologist,
- Joanne White, principal scientist, PHLS Communicable Disease Surveillance Centre,
- Zoltan Bozoky, project officer, Health Education Authority
Norman Begg and colleagues assess how adverse publicity damages vaccination programmes
Once again the media have succeeded in denting parents' confidence in childhood immunisation. Coverage of the first dose of MMR vaccine in the United Kingdom fell last quarter after adverse publicity in the press linking MMR vaccine to Crohn's disease (Communicable Disease Report 1998;8:41).
The national fall in vaccine coverage was 1%, although in 25 (20%) districts and health boards coverage fell by 2% or more. Altogether, about 2000 fewer children were vaccinated than in the previous quarter. The weight of scientific evidence has subsequently shown that these media reports were unfounded (BMJ 1998;316:166) and that there is no causal link between MMR vaccine and Crohn's disease. Nevertheless, the damage to parents' confidence has been done. The press rarely give much prominence to negative findings that exonerate the safety of a medical intervention. As Jonathan Swift put it: “Falsehood flies and truth comes limping after; so that when men come to be undeceived it is too late; the jest is over and the tale has had its effect.”
Adverse media reporting has previously affected coverage of MMR vaccine in other countries, notably Denmark, where coverage dropped to a record low in 1993 after a television programme attacking MMR vaccination. Unrepentant, the same TV channel broadcast another unbalanced anti-vaccination programme last November.
What the journalists do not report is that measles, mumps, and rubella still cause substantial morbidity in developed countries. Where vaccine coverage is low the incidence of disease is high. Deaths from measles are common in some European countries, and this is directly related to poor vaccine coverage (see 1). Measles has almost been eliminated in Britain, but high levels of population immunity (>90%) are needed to prevent the recurrence of epidemics. There are already warning signs—outbreaks of measles have recently been reported in Steiner schools in Yorkshire, Gloucestershire, and Hampshire, where children are not vaccinated for philosophical reasons. Transmission of measles among such pockets of unvaccinated children has the potential to cause outbreaks in the general population.
It would seem that MMR vaccine has become the victim of its own success. When disease elimination is close, attention inevitably shifts to the side effects of the vaccine. The latest findings from the Health Education Authority, which has been tracking a random sample of mothers with children aged 0–2 years since 1991, found that 8% of mothers now consider that the MMR vaccine presents a greater risk than the diseases it protects against and that 20% consider the vaccine to have a moderate or high risk of side effects. Mothers in social categories ABC1 were less confident about MMR safety and potential risks than their C2DE counterparts.
Perception of the severity of disease has also changed substantially. Since 1991 there has been a 7% drop among mothers who would strongly agree to have any future child immunised. Of these, 33% believe MMR presents substantial risks to their child, including brain damage, a rise of 7% since February 1997. In October 1994, just before the national immunisation campaign against measles and rubella, 55% of mothers considered measles to be a very serious illness; now only 20% do so. We should learn from the experience of pertussis, where a sustained, misinformed media campaign against the vaccine throughout the 1970s saw vaccine coverage drop from 81% to 31%. Pertussis immunisation was disrupted in many other countries by anti-vaccination movements, and these countries experienced a disease incidence up to 100 times greater than in countries where high coverage was maintained (Lancet 1998;351:356-61).
We are fortunate in Britain in having strong surveillance systems that are able to rapidly detects changes in vaccine coverage and disease incidence. We cannot, however, afford to let our guard drop. Now that the issue of MMR vaccine safety has been resolved in the scientific press, it is important to restore public confidence in the vaccine.