The Public Health Interventions Advisory Committee (PHIAC) took account of a number of factors and issues when developing the recommendations.
3.1 Childhood immunisation is an important part of the Healthy Child programme, formerly known as the Child Health Promotion programme. Children who are not up-to-date with vaccinations may also be behind on other Healthy Child programme activities – or may have other health needs. The parents (including those with parental responsibility) of these children and young people may need additional support, information and encouragement to ensure their children complete the vaccination programme.
3.2 The UK childhood immunisation schedule is timed to take into account when children are likely to come into contact with vaccine-preventable infections and when, physiologically, they can produce a protective immune response. It is still important to give vaccinations, even when there has been a delay. But the focus of this guidance is on ensuring children and young people receive them in line with the national recommended schedule.
3.3 There was little published evidence on information recording and monitoring systems. However, PHIAC considered that evidence from practice was a valid and appropriate basis for a recommendation. It also recognised the fundamental role that accurate records and effective information systems play in enabling services to identify and contact children and young people who may not be fully immunised.
3.4 Most published research on interventions to increase immunisation uptake is non-UK based. Nevertheless, PHIAC judged that some of the evidence was applicable to the UK.
3.5 Evidence from other countries suggests that legislation or a proof-of-immunisation requirement for entry to nursery or school does increase vaccine coverage. PHIAC noted that school entry offers an opportunity for checking immunisation status and to provide relevant advice and information. It believes this may be acceptable to parents, those with parental responsibility and schools. However, PHIAC considered that an over-reliance on school entry as a checkpoint for immunisation status could have an adverse impact on timely vaccination in the pre-school years.
3.6 PHIAC noted that research carried out around the time of the controversy over MMR may have been influenced by that controversy – and may become less relevant in the future. Research published in 1998 raised concerns about the safety of the MMR vaccine, suggesting a link with autism and certain bowel problems. As a result, some parents chose not to immunise their children, delayed the immunisation or only allowed their children to receive 1 of the 2 doses of the vaccine. Further extensive studies have found no evidence to link the vaccine to autism or chronic bowel conditions. However, despite advice from professionals and the Department of Health, some parents remain concerned. The subsequent reduction in vaccination coverage in England has led to outbreaks of measles. More recently, MMR vaccination coverage has slowly begun to increase.
3.7 PHIAC acknowledged that there may be various reasons why children and young people might not be up-to-date with their vaccinations. Logistical difficulties associated with large families have been identified as 1 factor. Other children and young people may be at risk of missing vaccinations because they are not in contact with primary care services. These include those who are homeless, asylum seekers and drug users (or whose parents are drug users). Children from minority ethnic groups and those whose first language is not English may also be more vulnerable, because services are not flexible enough and information is not provided in a language they understand. Some children from at-risk groups may be in contact with children's services and other health services – but not necessarily immunisation services. This includes young offenders, those in the care of child and adolescent mental health services and looked after children.
3.8 Vaccination against some infections can provide indirect benefits to people who are not immunised – so-called 'herd immunity'. The higher the proportion of the population who are vaccinated against an infection, the lower the proportion at risk of becoming infected (and the lower the chance of infection spreading within the population). People who have not been immunised (by choice or for medical reasons) and those in whom immunisation did not produce a protective immune response also benefit from this reduced transmission. Once the proportion of people vaccinated reaches a certain level, there may still be some onward transmission but no epidemics. This level varies for different infections, but it is over 95% coverage for measles. Even if vaccine coverage levels reach the level needed to prevent an epidemic, it is important to maintain these levels unless the infection has been eradicated globally. This is because an infected person may enter the country and could transmit the infection to susceptible people.
3.9 The human papillomavirus (HPV) immunisation programme for girls aged 12–13, and a catch-up programme for older girls and young women, was introduced in September 2008. PHIAC was unable to make specific recommendations related to HPV vaccination, as the UK programme was in its infancy.
3.10 Young people aged 16 and 17 years can be assumed to have the same capacity as an adult to consent to immunisations and do not need parental consent, unless there is reason to believe that they do not have that capacity. Young people under the age of 16 can also give consent to immunisation if they fully understand what is proposed. PHIAC recognised that some practitioners, including teachers and social care workers, may not be aware of this. More detailed information about consent is available from the Department of Health's Green Book and the DH website.
3.11 PHIAC recognised the importance of leadership from GPs and health visitors, working with a wide range of professionals and staff from different sectors, to provide effective immunisation services for all children and young people. GPs and health visitors can also provide important additional support to those working with children who are at increased risk of not being immunised and their families.
3.12 PHIAC noted that health visitors have the lead role in the delivery of the Healthy Child programme. The health visiting team is responsible for working with parents and families to ensure children aged under 5 years are offered – and are able to receive – all vaccinations, as specified in the immunisation schedule.
3.13 PHIAC recognised the importance of information sharing and communication between health and social care services to ensure looked after children's records are passed on if they move.
3.14 PHIAC focused on the infant hepatitis B vaccination programme because the earlier a child is infected the more likely they are to become a chronic carrier and develop cirrhosis and liver cancer. In addition, this programme is not well understood nor widely implemented. PHIAC did not consider the hepatitis B vaccination programme for any other age group.
3.15 Economic modelling was carried out for measles vaccination, as an important example of a universal vaccination in the UK. It was also carried out for hepatitis B vaccination among at-risk neonates, as an important example of a targeted vaccination in the UK.
3.16 Economic modelling showed that, at current levels of immunisation, efforts to increase uptake of the measles vaccine were highly cost effective in groups with both high and low immunisation coverage. Increasing uptake among low-coverage groups was shown to be marginally more efficient than increasing uptake among high-coverage groups. (This is true if the cost per child were the same in each group.) It would also do more to reduce health inequalities. The modelling suggested that home visits (likely to be the most expensive means of increasing coverage by 1 percentage point) would be a cost effective use of NHS resources. The implication is that almost any method of increasing coverage would be cost effective. The model underestimated the cost effectiveness of the MMR vaccine because it did not ascribe any benefits to the concurrent prevention of mumps and rubella infection. (The vaccine offers simultaneous protection against 3 different infections.)
3.17 Economic modelling demonstrates that the current UK infant hepatitis B vaccination programme, whereby immunisation is targeted at babies of mothers who are hepatitis B-positive, is cost saving. The analysis suggests that considerable additional resources could be invested to improve timely uptake, and the programme would still be cost effective.