Dr. Marko Petrovic, MB, BS, MPH, FRCS, DFPHM
Specialist Registrar in Public Health Medicine

Dr. Richard J Roberts, MB, BS, BSc, DCH, MPH, MFPHM
Consultant in Public Health Medicine
Department of Public Health Medicine
North Wales Health Authority

Dr. Mary Ramsay, BSc, MB, BS, MRCP, MSc, FFPHM
Consultant Epidemiologist
Public Health Laboratory Service
Communicable Disease Surveillance Centre
 
 

Statement of contribution

Norman Begg and Richard Roberts had the initial ideas for the research.
Anthony Swan provided statistical advice regarding study design.
Marko Petrovic, Mary Ramsay and Richard Roberts designed the study, interpreted the data, participated in writing the paper and approved the final draft.
Marko Petrovic and André Charlett analysed the data.
 
 
 

Word count: 3,859 (excluding title page and tables, including references and acknowledgements)

Key MeSH headings: measles vaccine
                                 immunisation
                                 health personnel
                                 knowledge, attitudes, practice

Abstract

Objectives

To provide a profile of knowledge, attitudes and practice of health professionals regarding the measles, mumps and rubella (MMR) vaccine, with emphasis on the second dose.

Design

A cross-sectional study using a self-administered postal questionnaire.

Setting

North Wales Health Authority, Wales, UK, 1998.

Subjects

All health visitors and practice nurses, and a 50% random sample of general practitioners (GPs).

Main Outcome measures

The knowledge, attitudes and practice of respondents regarding the MMR vaccine.

Results

47.8% (220/460) of professionals had reservations about, and 3.3% (15/460) disagreed completely with, the second dose of MMR vaccine.

The health visitor was thought to be the best source of initial advice regarding the second MMR vaccine, but only 20.3% (28/138) would recommend the second dose to a parent that was unsure.

61.4% (86/140) of health visitors, as opposed to 46.2% (73/158) of GPs, reported feeling very confident about explaining the rationale behind a two-dose schedule to a well-informed parent.

33.1% (54/163) of practice nurses stated that Crohn’s disease was very likely, or possibly, associated with MMR vaccine, whilst 26.8% (44/164) stated that this was the case with autism.

17.1% (27/158) of GPs reported that they had not read the MMR section in the "green book", and 28.9% (44/152) reported that they had not received the Health Education Authority MMR factsheet.

Conclusions

There is much variation in knowledge and practice among health professionals regarding the second dose of MMR vaccine. Although good written resources exist, many practitioners are unaware of, or do not use, them. There is a need for local educational initiatives to address these issues.

Introduction

On 1^st October 1996 a second dose of measles, mumps and rubella (MMR) vaccine was introduced into the United Kingdom (UK) childhood immunisation programme to improve the effectiveness of MMR vaccination (1). In introducing a second routine dose of MMR, the UK has joined the 133 countries in the world that use a two-dose measles vaccination schedule, including the United States, China and the majority of countries in the European Region of the World Health Organization (WHO) (2). In Finland, the use of a two-dose schedule has eliminated indigenous measles, mumps and rubella (3), and MMR vaccine has been shown to be both effective and safe (4, 5). Despite this, recent adverse publicity has threatened to derail the UK measles control and elimination programme, and with it the target of eliminating indigenous measles in the European region of the WHO by 2007 (6).

Because measles elimination cannot be achieved with a one-dose strategy, the second dose of MMR is essential (7, 8). Therefore, as health professionals are key opinion formers in the public’s perception of the risks and benefits of immunisation, it is worrying that anecdotal evidence suggests concerns, particularly amongst health visitors and practice nurses, about the second dose of MMR vaccine (9). We undertook a descriptive study of the knowledge, attitudes and practice of this key group regarding, in particular, the second dose of MMR vaccine, with the aim of identifying those aspects that may be having an adverse effect on uptake. This would facilitate interventions that targeted specific shortcomings.

Methods

We used an anonymous self-administered postal questionnaire to conduct a descriptive survey of knowledge, attitudes and practice. It contained 16 questions, with some opportunity to make open comments. It was sent between May 8^th-11^th 1998, together with a covering letter, to all the health visitors and practice nurses, and to a 50% random sample of general practitioners (GPs) in the North Wales Health Authority area. A second mailing was undertaken one month later.

Based on uptake of two doses of measles-containing vaccine among children from the same birth cohort that were registered with them, health visitors were assigned to an uptake third and GPs to an uptake quarter. GPs with a small number of children from this 1993 cohort (less than half the mean per GP) were excluded from the construction of uptake quartiles. To compare answers with uptake, the percentages of respondents in the upper versus lower quarter/third were compared.

Statistical analysis was performed using Epi-Info 6 (10) and SPSS for Windows 8.0.1 (11).
 

Results

Response rate

Questionnaires were sent to 206 GPs, 148 health visitors and 239 practice nurses. The response rate was 80.1% (165/206), 94.6% (140/148) and 85.4% (204/239) respectively.

Giving immunisation advice to parents

All health visitors stated that they give immunisation advice to parents. However, 4.2% of GPs (7/165) and 17.2% of practice nurses (35/204) reported that they do not, and they were excluded from further analysis, as were four practice nurses who did not respond to this question.

About immunisation and MMR vaccine in general

-Information sources and their use

3.2% (5/156) of GPs reported not having easy access to a copy of Immunisation against Infectious Disease (the "green book") (5), compared to less than 0.7% (2/303) of other health professionals. 17.1% (27/158) of GPs said that they had not read the section in the "green book" on MMR. The majority of health professionals (69.3% (321/463) reported that it is an extremely useful reference book for immunisations in general.

28.9% (44/152) of GPs, 10.9% (15/138) of health visitors and 13.7% (22/161) of practice nurses reported that they had not received the Health Education Authority MMR factsheet (12). Of those who reported that they had received it, 91.4% of GPs (96/105), 95.8% (114/119) of health visitors and 97.8% (133/136) of practice nurses stated that it is extremely or moderately useful.

Views on association of possible side-effects with MMR vaccine

33.1% (54/163) of practice nurses stated that an association between MMR vaccine and Crohn’s Disease is very likely or possible, whilst 26.8% (44/164) stated that this was the case with autism, and 11.8% (19/161) with asthma. (See tables 1 and 2) Practice nurses were significantly more likely than GPs to express such a view for Crohn’s disease (OR 3.6, 95% CI 2.0-6.5), autism (OR 2.8, 95% CI 1.6-5.0) and asthma (OR 2.5, 95% CI 1.1-6.0). They were also more likely than health visitors to express such a view for Crohn’s disease (OR 4.3, 95% CI 2.3-8.1), autism (OR 5.0, 95% CI 2.4-10.4) and asthma (OR 3.0, 95% CI 1.2-7.8).

77.2% (122/158) of GPs, 80.6% (112/139) of health visitors and 81.3% (130/160) of practice nurses stated that they either do not know, or think it unlikely, that idiopathic thrombocytopaenic purpura is associated with MMR vaccine.

Was training/information about MMR vaccine adequate?

46.2% (72/156) of GPs, 70.3% (97/138) of health visitors and 76.3% (122/160) of practice nurses reported that they would have liked more information/training on the MMR vaccine in general.

About the second MMR vaccine

Best person to give initial advice about MMR2:
The health visitor was named by 57.8% (85/147) of GPs, 69.3% (95/137) of health visitors, and 40.9% (66/161) of practice nurses as the best person to give the initial advice about the second dose of MMR vaccine. The next most frequent choice was the GP, suggested by 20.4% (30/147) of GPs, 10.2% (14/137) of health visitors and 26.0% (42/161) of practice nurses. Practice nurses were chosen by 17% (25/147) of GPs, 3.6% (5/137) of health visitors and 19.9% (32/161) of practice nurses.

Confidence in explaining the rationale behind a two-dose schedule to a "well-informed parent"

Only 46.2% (73/158) of GPs and 40.2% (66/164) of practice nurses said that they would feel very confident in this situation, compared with 61.4% (86/140) of health visitors. Health visitors were significantly more likely to state that they would be very confident (as opposed to any other response) than either GPs (OR 1.9, 95% CI 1.2-2.9) or practice nurses (OR 2.4, 95% CI 1.5-3.8). For all three groups, those who stated that they would be very confident were significantly more likely to agree completely with the policy of giving the second dose of MMR vaccine. (GPs: OR 5.2, 95% CI 2.6-10.4, health visitors: OR 5.3, 95% CI 2.4-11.9, practice nurses: OR 2.1, 95% CI 1.1-4.0.)

GPs and health visitors who stated that they would be very confident of explaining the rationale had higher uptake (OR: 1.8 (95% CI 0.7-4.9) for GPs, 2.1 (95% CI 0.9-4.6) for health visitors).

Thirty-nine health professionals commented on various problems with the rationale. Some had difficulty in accepting the concept of herd immunity:

"I find it difficult advising a parent that their child required a 2^nd dose in order to ensure "herd" immunity when they may themselves already be immune."

"The second dose is only really benefiting a few."

Others doubted the necessity of a second dose:

"I thought myself that one dose did the trick."

"I disagree with the 2^nd dose...How do we know that 10% of children following the 1^st dose MMR are not producing antibodies. Where is the evidence?"

Others questioned using the second dose of MMR vaccine as an opportunity for giving the first dose in non-attenders.

"Those parents who don’t give the first dose are the ones who tend not to give the 2^nd dose..."

How health professionals advise those parents who remain unsure about the second dose of MMR vaccine

Having answered all of the parent’s questions, but faced with a parent who was still unsure, 72.4% (113/156) of GPs said that they would recommend the second dose of MMR vaccine, significantly more than practice nurses (42.2% (68/161)) (OR 3.6, 95% CI 2.2-5.9), or health visitors (20.3% (28/138)) (OR 10.3, 95% CI 5.8-18.5). Those who said that they agree completely with the policy of giving the second dose were significantly more likely to state that they would recommend it in such a situation, compared to those who gave another response. (GPs: OR 5.8, 95% CI 2.6-13.1, health visitors: OR 5.1, 95% CI 2.1-12.8, practice nurses: OR 5.2, 95% CI 2.6-10.2).

What health professionals do when they don’t have the answer

Faced with a situation where, despite having the relevant literature etc. to hand, they were unable to answer a parent who still had doubts about the second dose of MMR vaccine, 17.5% (27/154) of GPs reported that they would do nothing further.

The majority of health professionals stated that they would refer the parent either to a practice colleague (19.5% (30/154) of GPs, 22.1% (30/136) of health visitors and 53.4% (86/161) of practice nurses), or to the community paediatrician (48.7% (75/154) of GPs, 39.7% (54/136) of health visitors and 25.5% (41/161) of practice nurses).

Measuring measles antibody levels

In a situation where a parent still had doubts about the second dose of MMR vaccine, 50.6% (80/158) of GPs, 55.5% (75/135) of health visitors and 45.1% (74/164) of practice nurses stated that they would agree, either entirely or reluctantly, with measuring measles antibody levels.

Was information/training on the introduction of MMR2 adequate?

58.3% (91/156) of GPs, 67.9% (93/137) of health visitors and 82.5% (132/160) of practice nurses stated that they would have liked more information/training on the rationale behind the introduction of the second dose of MMR vaccine.

Do health professionals agree with the policy of giving a second dose of MMR? (See table 3)

40.1% (63/157) of GPs, 48.9% (68/139) of health visitors and 54.3% (89/164) of practice nurses, stated that they have reservations about the policy of giving the second dose of MMR vaccine.

GPs were more likely than health visitors (OR 1.7, 95% CI 1.1-2.8) or practice nurses (OR 1.7, 95% CI 1.1-2.7) to agree completely with the policy. Agreeing completely with the policy was not significantly associated with higher uptake of two doses of a measles-containing vaccine for any health professional.

Twenty-nine health professionals commented that administration of the vaccine with the pre-school boosters was a reason for their reservation. A typical comment was:

"As a practice nurse, I find giving 2 injections to pre-school children very distressing to child, parent and myself."

Ten health professionals had reservations about giving the vaccine to their own children. Comments included:

"...have not given my...children the second dose...I know of at least one GP practice who is not advocating 2^nd MMR and I applaud them."

"I don’t influence parents in any way...I would be frightened to urge parents...in case there were problems afterwards. I would not want anybody to blame me for persuading them."
 

Discussion

This is the first survey of knowledge, attitudes and practice of health professionals in North Wales with particular emphasis on the second dose of MMR vaccine. It has highlighted several areas where local knowledge or practice varies from national policy and scientific evidence. Because of the good response rate, and the fact that all health visitors and practice nurses, and 50% of GPs, were included, it is likely these results reflect the views of health professionals in North Wales.

It is also reasonable to assume that the findings in this survey are generalisable to other UK health professionals. In North Wales, as in the UK as a whole, most childhood vaccinations are given in general practice, although some are given at child health clinics. Around the time of the survey, coverage of the first dose of MMR vaccine in North Wales was similar to the UK as a whole. In North Wales, uptake was 88.7% in children reaching their second birthday during the evaluation quarter April to June 1998 (D Rh Thomas, CDSC Wales, personal communication), compared to 89.7% (district/health board range 68.7% - 97.8%) in the UK (13).

Everyone that gives immunisation advice should be familiar with up-to-date national policy and scientific evidence, including the evidence that relates to side-effects of vaccination. The book Immunisation against Infectious Disease (the "green book") (5) provides clear and authoritative advice on all aspects of immunisation. Despite this, 17.1% (27/158) of GPs in our survey who gave immunisation advice to parents, said that they had not read the section on MMR. Similarly, over a quarter of GPs and over 10% of the other two groups reported that they had not received a copy of the Health Education Authority MMR factsheet (12), despite it having been circulated to all practices.

Knowledge of adverse effects of MMR vaccine was poor. Over three-quarters of each professional group did not know, or thought it unlikely, that idiopathic thrombocytopaenic purpura (ITP) was associated with MMR vaccine, despite a well-documented association (14). The latter association is also clearly pointed out in Immunisation against Infectious Diseases (5) and in the Health Education Authority MMR Factsheet (12), yet this message is obviously not reaching its target audience.

In contrast, and despite authoritative expert advice to the contrary (15), over a quarter of practice nurses believed that autism was very likely, or possibly, associated with MMR vaccine, whilst a third believed that it was very likely, or possibly, associated with Crohn’s disease. This survey did, however, take place soon after publication of a criticised paper that suggested an association between MMR vaccine and ileal-lymphoid nodular hyperplasia and autism (16), which was picked up in the general press. This may have influenced some of the replies. Subsequent data refuting the link between autism and MMR vaccine may help to reduce the proportion of professionals believing that there may be a link (17).

The most popular choice of health professional to give the initial advice about the second MMR vaccine was the health visitor, followed by the GP and the practice nurse. It is reassuring, then, that health visitors were significantly more likely than their GP or practice nurse colleagues to be very confident of being able to explain the rationale behind the second dose, although we have no way of knowing whether this confidence is justified. However, only a fifth of health visitors would advise the second dose when faced with a parent who was still unsure, whereas GPs were much more likely to continue to recommend vaccine to an unsure parent. This may represent a difference in professional styles, with GPs likely to be more prescriptive, or it may be that health visitors had easier access to a second source of advice by referral to the GP. There is a danger, however, that parents who do not receive a positive recommendation on their first visit will not return for a second consultation.

Inevitably, there are situations in clinical practice where a health professional, despite having all the relevant literature to hand, is posed a question that they are unable to answer. It is of concern that, faced with a parent asking about the second MMR vaccine, 17.5% (27/154) of GPs would do nothing further in such a situation. As there is no association between this type of practice and coverage of MMR vaccine, these circumstances may be uncommon.

Over a half of GPs and health visitors would agree, either entirely or reluctantly, with antibody testing being done. This is an important issue because measles/MMR vaccine is safe in immune children and because there are many problems with antibody testing as part of the measles control programme. Firstly, taking blood from a 4 year-old child is an invasive procedure. Secondly, universal testing and recall of non-immune children would add greatly to the cost of the measles vaccination programme and would be logistically difficult. Thirdly, there is a possibility of misclassification. Those children whose test was a false positive would not be offered another dose of vaccine and would remain at risk. Finally, the emphasis on measles may endanger control of the other two diseases, mumps and rubella, with their attendant consequences. With anecdotal reports locally of increasing numbers of parents asking for antibody testing, this is an area that will need to be addressed.

Few health professionals disagreed completely with the second dose of MMR vaccine, although around a half of respondents had reservations. We found that confidence in explaining the rationale for the second MMR dose to a well-informed parent was strongly associated with agreeing with the policy and the latter with positively recommending the second dose to a wavering parent. It is plausible, therefore, that meeting the demand for education and improving professionals’ understanding of the rationale for the second MMR will increase the number of parents who receive a positive recommendation from health professionals.

Respondents who said that they agreed with, but had reservations about the second dose, form a sizeable group that need to be targeted. The most commonly expressed reservations were the timing of the vaccine and the necessity of a second dose. The first reservation could easily be overcome by adopting a more flexible approach and giving the second MMR earlier at, for example, the 3¼ years developmental check. The second reservation clearly emphasises the need for further education.

This study has shown there are many areas where sizeable numbers of respondents have knowledge or practice that differs from current national policy and scientific evidence. It has also revealed that the majority of respondents would have liked more training on the rationale behind the second dose. If, as suggested by our health professionals, health visitors become the key initial source of advice around the time of the second dose of MMR vaccine, it is essential that their advice is underpinned by sound knowledge and strong support for the current measles control programme. Our survey suggests that an educational programme must impart key information from existing national sources, including current evidence regarding the side-effects of vaccination. It is important that the scientific rationale behind a two-dose MMR policy, and the reasons for not recommending antibody testing, are clearly explained. Finally, the information that is provided must remain consistent, from national sources of advice, via health professionals, through to parents.

In response to these findings, we are constructing an MMR resource pack that contains evidence-based information about MMR immunisation and is designed for use by health professionals during consultations with parents. Future work could also include a national survey, using a sample of health professionals, as it would be important to know if the variations in knowledge and practice that this survey has demonstrated are replicated nationally. This could form part of an ongoing programme to monitor the effectiveness of professional communication in the childhood vaccination programme.

References

1. CDSC. A second dose of MMR vaccine for children in the United Kingdom. Comm Dis Rep CDR Wkly 1996; 6: 259.
2. Centers for Disease Control and Prevention. Advances in global measles control and elimination: summary of the 1997 international meeting. MMWR 1998; 47 (RR-11): 2-11.
3. Petola H, Heinonen OP, Valle M, Paunio M, Virtanen M, Karanko V, et al. The elimination of indigenous measles, mumps and rubella from Finland by a 12-year, two-dose vaccination programme. N Engl J Med 1994; 331: 1397-1402.
4. Measles and mumps vaccines. In: Stratton KR, Howe CJ, Johnston RB Jr, editors. Adverse events associated with childhood vaccines: evidence bearing on causality. Washington, D.C.: Institute of Medicine.
5. Department of Health. Immunisation against Infectious Disease. London HMSO, 1996.
6. World Health Organization. Health 21: The health for all policy framework for the WHO European Region. (European health for All Series; No. 6) Copenhagen: World Health Organization, Regional Office for Europe, 1999.
7. Gay NJ, Hesketh LM, Morgan-Capner P, Miller E. Interpretation of serological surveillance data for measles using mathematical models: implications for vaccine strategy. Epidemiol Infect 1995; 115: 139-156.
8. Cutts FT, Markowitz LE. Successes and failures in measles control. J Infect Dis 1994; 170 (Suppl 1): S32-S41.
9. Roberts N. Why are practice nurses scared of MMR2? GP 1998; Jan 23: 63.
10. Dean AG, Dean JA, Coulombier D, Brendel KA, Smith DC, Burton AH, et al. Epi-Info, version 6: A word-processing, database, and statistics program for public health on IBM-compatible microcomputers. Centers for Disease Control and Prevention, Atlanta, Georgia, USA, 1995.
11. SPSS for windows. Release 8.0.1, 1998.
12. Health Education Authority. MMR Immunisation Factsheet. London HEA, 1997.
13. CDSC. COVER/Korner: April to June 1998. Comm Dis Rep CDR Wkly 1998; 8: 345-346.
14. Farrington P, Pugh S, Colville A, Flower A, Nash J, Morgan-Capner P, et al. A new method for active surveillance of adverse events from diphtheria/tetanus/pertussis and measles/mumps/rubella vaccines. Lancet 1995; 345: 567-569.
15. Chief Medical Officer. Measles, measles mumps rubella (MMR) vaccine, Crohn’s disease and autism. Cardiff: Welsh Office, 1998 Mar. No: CMO (98) 7.
16. Wakefield AJ, Murch SH, Anthony A, Linnell J, Casson DM, Malik M, et al. Ileal–lymphoid nodular hyperplasia, non-specific colitis, and pervasive developmental disorder in children. Lancet 1998; 351: 637-641.
17. Taylor B, Miller E, Farrington CP, Petropoulos MC, Favot-Mayaud I, Li J, Waight PA. Autism and measles, mumps, and rubella vaccine: no epidemiological evidence for a causal association. Lancet 1999; 353: 2026-2029

Clwydian Community Health Trust
William Poley facilitated the study in Clwydian Community Health Trust.

Gwynedd Community Health Trust
Graham Wharton facilitated the study in Gwynedd Community Health Trust.

Health Education Authority
Zoltan Bozoky provided information about HEA work in the subject area covered by this study.

North Wales Health Authority
Di Barnes and Glenys Proffit provided initial ideas regarding factors that may affect uptake of childhood immunisations and facilitated the study amongst practice nurses.

Sue Davies, Hannah Potter, Gill Shawcross and Sue Williams provided logistical and secretarial support.

Contractor Services Staff provided data on local General Practitioners and Practice Nurses.

Welsh Health Common Services Authority, Health Solutions Wales
John King and staff provided data from the Welsh Child Health Computer System.

Others
North Wales health professionals who participated in piloting of the questionnaire.

Table 1Health professionals views’ on the likelihood of an association between MMR vaccine and autism
 

Table 2 Health professionals’ views on the likelihood of an association between MMR vaccine and Crohn’s disease
 

Table 3 Do health professionals agree with the policy of giving a second dose of MMR?