Second dose of measles, mumps, and rubella vaccine: questionnaire survey of health professionals

Introduction

On 1 October 1996 a second dose of the measles, mumps, and rubella (MMR) vaccine was added to the United Kingdom's childhood immunisation programme.1 In doing this, the United Kingdom has become one of 38 countries in the World Health Organization's European region that use a two dose vaccination schedule for measles2; among these Finland is one of the countries that has eliminated indigenous measles, mumps, and rubella.3 The vaccine has been shown to be effective and to have a good safety record, 4 5 yet recent adverse publicity in the United Kingdom has threatened to derail its vaccination programme and, with it, the target of eliminating indigenous measles in the WHO's European region by 2007.6

Measles cannot be eliminated with a single dose of the vaccine, 7 8 so anecdotal reports of concern among health professionals about the second dose of the MMR vaccine are worrying.9 We undertook a questionnaire survey of health professionals to identify aspects of their knowledge, attitudes, and practices regarding MMR vaccination that may have an adverse effect on its coverage. This would facilitate interventions that could target these shortcomings.

Methods

We used an anonymous, self administered postal questionnaire comprising 16 questions and an opportunity to make open comments. It was sent between 8 and 11 May 1998, with a second mailing one month later, to all the health visitors and practice nurses and to a 50% random sample (selected using computer generated random numbers) of general practitioners in the North Wales Health Authority area. We used Epi-Info 610 and SPSS for Windows (version 8.0.1) to analyse the data.

Results

Overall, 80% of general practitioners (165/206), 95% of health visitors (140/148), and 85% of practice nurses (204/239) responded to the survey. All the health visitors stated that they give advice on immunisation to parents, but 4% of the general practitioners (7/165) and 17% of the practice nurses (35/204) reported that they do not give advice on immunisation; they were excluded from further analysis, as were four practice nurses who did not respond to this question.

Discussion

This is the first published survey in the United Kingdom of the knowledge, attitudes, and practices of health professionals regarding the second dose of the MMR vaccine. It has highlighted several ways in which local knowledge or practice varies from national policy and scientific evidence. Because of the good response rate it is likely that these results accurately reflect the views of health professionals in north Wales. The findings are also likely to be generalisable to other areas of the United Kingdom. The coverage of MMR vaccination in the North Wales Health Authority area was similar to that in the United Kingdom as a whole at the time of the survey (D Rh Thomas, Communicable Disease Surveillance Centre, Wales, personal communication),12 and most childhood vaccinations in the area are given in general practice.

Immunisation Against Infectious Disease (the “green book”)5 provides authoritative advice on immunisation. Despite this, some general practitioners who gave immunisation advice to parents said that they had not read the section on MMR. Similarly, more than a quarter of general practitioners and more than 10% of the other two groups reported that they had not received a copy of the Health Education Authority's MMR factsheet,11 despite its having been circulated to all general practices.

Knowledge about the adverse effects of the vaccine was variable. More than three quarters of the respondents were not aware of the documented association between the MMR vaccine and idiopathic thrombocytopenic purpura.13 Despite expert advice to the contrary,14 a substantial proportion of practice nurses believed that autism and Crohn's disease may be linked to the vaccine. Our survey took place soon after the publication of a much criticised paper that reported that a small series of children who had ileal-lymphoid nodular hyperplasia developed autistic symptoms after MMR vaccination 15 16; this influence may have been reduced by subsequent findings.17

Health visitors were seen as the best initial source of advice about the second dose of the vaccine and were more confident than the other groups in explaining its rationale. Even so, when faced with a wavering parent only a fifth of health visitors would advise the second dose without referral to a colleague or a community paediatrician.

Just over half of the respondents said that they would agree, either entirely or reluctantly, to antibody testing. This is of concern because vaccines containing live, attenuated measles virus are safe in immune children and therefore antibody testing in children is unnecessary as well as impractical.

Few respondents disagreed completely with giving a second dose of the vaccine, although around a half had reservations. We found that respondents' confidence in explaining the rationale of the second dose to a well informed parent was strongly associated with their agreeing with the policy, and that agreement was strongly associated with recommending the second dose to a wavering parent. It is plausible, therefore, that meeting the demand for education and information and improving understanding among health professionals of the rationale of the second dose will increase the number of positive recommendations.

In response to the findings of this survey the North Wales Health Authority's department of public health is constructing a measles, mumps, and rubella vaccination resource pack that contains evidence based information and is designed for use by health professionals during consultation with parents. Future work could include national monitoring of knowledge and practice of healthcare professionals to evaluate and inform the effectiveness of professional communication in the childhood immunisation programme.