Results

Immunisation status was ascertained for 1000 children, mean age 1.5 years. Seven hundred and ninety eight (80%) had been immunised at the appropriate age. Nineteen children were not protected against pertussis because of parental anxieties about the safety of the vaccine (16 cases) or because of a presumed reaction against the first or second pertussis vaccination (three cases). Forty one (4.1%) had missed a scheduled immunisation because of their acute illness, or were due a scheduled immunisation shortly after discharge. One hundred and forty two (14.2%) had missed an age appropriate immunisation. Reasons for missed immunisations are given in table 1. None was a valid contraindication. The age distribution of the under immunised children was as follows: first immunisation, median age 5 months (range 3–42 months); second immunisation, median age 6 months (range 4–35 months); third immunisation, median age 8 months (range 5–36 months); first measles– mumps–rubella (MMR), median age 20 months (range 16–66 months); second MMR, median age 58 months (range 55–66 months).

For 49 (5%) children no computer or child health record was available because of family mobility. There were differences between the child’s immunisation status as reported by the carers and the official record in 90 (9.5%) of the remaining 951 admissions. In 44 (49%) cases the mother reported more vaccinations received than officially recorded, while in 20 (22%) cases fewer vaccinations were reported by the mother than officially recorded. In 14 (16%) cases no record was obtained from the family because they could not remember (five cases) or because they were not available to ask. In 12 (13%) cases there was no record of recent immunisations on the computer database but it was believed reasonable to attribute this to acceptable administrative delay.

Forty three (23%) of the 183 children who were due an immunisation or were under immunised were offered immunisation on the ward. Twenty eight (65%) accepted, 26 receiving diphtheria, tetanus, pertussis, Hib, and oral poliomyelitis, and one receiving MMR. Twenty (71%) of these 27 children were brought fully up to date with their immunisations. Of the 15 carers who refused immunisation on the ward, 10 preferred to have this done by their general practitioner after discharge, three felt that their child was still not well enough, one remained concerned about vaccine safety, and in one case no reason was documented. In none of the other 140 children did the junior ward doctor document that appropriate vaccination was deferred because of continuing signs or symptoms of acute illness at discharge.

Discussion

Immunisation is effective preventive medicine.1Infectious diseases can be eliminated when the susceptible population is reduced below a critical number so that each primary case fails to produce at least one secondary case. It is estimated that this can be achieved for measles, mumps, pertussis, and rubella when immunisation uptake is between 92–96%.4 Across the world we fail to realise these levels, especially in inner city areas where age appropriate immunisation may only be achieved in 40–60% of two year olds.5-9 This under immunised cohort remains a reservoir for infectious diseases in the community and has been shown to play a significant role in mini-epidemics of measles in the USA.6 10-12 These children are also the most likely to suffer complications.11 The World Health Organisation set a target of 90% uptake for the primary immunisation schedule in preschool children in 1984 as a prerequisite to the elimination of indigenous measles, poliomyelitis, diphtheria, and congenital rubella.13 In 1992 a target of 95% was set for England.14

Preschool children require three diphtheria, tetanus, pertussis, Hib and oral poliomyelitis immunisations in the first four months, one MMR at 12–15 months, and diphtheria, tetanus, poliomyelitis and MMR boosters three years after completion of the primary course to meet the recommended UK schedule. Reasons for under immunisation are many and complex, ranging through professional health carers misunderstanding of what constitutes a valid contraindication, to organisational problems reducing opportunities, to parental fears of vaccine side effects, often inflamed by unbalanced media reports. In Ehresmann’s study of kindergarten age Minnesota preschoolers in the USA, as each additional immunisation due date was reached the percentage of children behind the recommended schedule increased—for example, from 21% at 12 months, to 55% at 16 months, then to 64% at 19 months.9 Similarly in the UK, compliance with the national immunisation schedule can fall below 50% by the time a child reaches 5 years of age.15The UK Cover/Korner data for the northern and Yorkshire region in the final quarter of 1995 showed overall uptake at 95% or above at 24 months of age for only diphtheria, tetanus, poliomyelitis, and Hib and there were important differences between districts. Leeds fell below 95% for all vaccines. In the first quarter of 1998 overall coverage for the northern and Yorkshire region was still below the target for pertussis and MMR vaccines, and Leeds was still not achieving 95% uptake for any part of the immunisation programme. Similar deficiencies occur elsewhere. Despite some success in achieving catch up immunisation between the first and second birthday in Tameside and Glossop, 11% of two year olds remained incompletely immunised.15

Particularly vulnerable groups of children have been identified. The use of preventive medical opportunities varies greatly between the “haves” and “have nots” throughout our society.16 17 In areas of social deprivation immunisation may be rated as less important than in higher socioeconomic status groups.18 19 Immunisation uptake is lower for children from mobile families and for those of single and poorly educated mothers who may find access to services more difficult, especially for children lower in the birth order in large families.6 7 9 11 20-23 These families may suffer particularly from an appointment only system and long waiting times in clinics. In the USA age appropriate immunisation is more complete in white than black or hispanic preschool age children24 and similar discrimination may exist in the UK.

We must alter our concept of immunisation as events that occur at discrete points in time and see it as a continuum.9 We must educate junior doctors and medical students to see each contact between children and the health care system as an opportunity to review their immunisation status and update where indicated with all the vaccines for which the children are eligible.25 26 Missed opportunities to immunise are a major reason for the continuing under immunisation of vulnerable children.6 8 11 12 27 28Accident and emergency visits should ideally be used to increase immunisation uptake but have inherent logistic difficulties—for example, staffing levels, finding time to confirm given immunisation status. Vaccinating at well-child care visits alone is unlikely to make sufficient impact.29 Barriers to immunisation in the community—for example, appointments, access, waiting times—do not exist in hospital, and the admission process provides time to take an immunisation history and verify this against official records.

Immunisation histories obtained from carers are not reliable. We found that where there were discrepancies between the mother’s recollection of the vaccination history and the official records, in 49% of cases the former overestimated the number of vaccinations received and in a further 16% no immunisation history had been given. Others have found a similar degree of inaccuracy in parental memory.5 7 30However, like others we found that with commitment accurate information can be obtained for most admissions from personal child health records and the local computer database without disrupting daily work.30 31 Even if not available at admission the former can be requested. Unfortunately, they are often not used by doctors.5 Access to health authority records is not difficult,30 but this route to verification of immunisation status is also not routinely used. Bell reported an average of only 1.5 telephone calls to the primary care provider per child to confirm immunisation status in 86% of over 2000 admissions.32 Informative contact with the computer database took only one telephone call and one to two minutes for most patients in our study, a minor addition to routine workload that allowed verification of vaccinations received in 94% of 1000 patients. Nonetheless, casual history taking which will underestimate the number of under immunised children2 is common.5 7 33

Immunisation in hospital can make an important contribution to a vulnerable group of children,5 but only if it is considered important by all medical staff, and a routine system is introduced for screening and vaccinating.2 3 30 We found 142 children who had missed an age appropriate immunisation and a further 41 children who were due a scheduled immunisation in 1000 admissions. None had a valid contraindication to vaccination, and signs and symptoms of the acute illness had resolved. Despite the ongoing study that necessitated accurate documentation of immunisation status, only 43 of 183 eligible children were offered immunisation on our ward, but 28 of these parents accepted and arrangements were made to catch up with immunisations at their general practitioners for a further 10. Others have reported similar possibilities for opportunistic immunisation of hospitalised children and a similar professional disinterest in this most effective form of preventive medicine.7 30 32 33 Little progress has been made over the last decade. Bell increased the percentage of fully immunised children from 44% on admission to 70% at discharge, but only by creating a specialised infrastructure including an immunisation team consisting of doctor, nurse coordinator, and assistant.32Junior doctors must be convinced of the efficacy and importance of the childhood immunisation programme because, although encouragement by senior doctors is essential, the responsibility for offering and administering vaccination must be with the junior staff, with the average length of stay of acute admissions being only two to three days. Better vaccination uptake may be obtained by offering catch up immunisation in outpatient follow up clinics. However, this may overload already stretched outpatient services and committed staff can achieve high immunisation uptake on the ward.30 31 One hundred per cent effort by doctors in the context of the 65% acceptance rate found in our study would have resulted in catch up immunisation in 9.2% of the 1000 admissions.

In conclusion we have shown that a large percentage of preschool age children admitted to hospital are under immunised, that accurate immunisation histories can be obtained without disrupting ward routine, and that a large majority of parents accept the offer of catch up immunisation during their child’s inpatient stay. Unfortunately our study also confirms that there is a pervasive disinterest in providing this service among doctors in training. As inpatient immunisation is rarely practised, the assumption is that enthusiasm for it is also unlikely to be prevalent among consultant paediatricians. We recommend that the importance of immunising children is emphasised at medical school and in subsequent training, that children’s immunisation status is accurately documented at admission from official records and appended to the front of the child’s charts, that any under immunisation is highlighted in the acute problem list, that any needed vaccines are given on the day of discharge, and that the general practitioner is fully informed.