The immunisation schedule in the UK frequently changes and this emphasises the need for practice nurses to remain familiar with what the changes are, and why they have occurred. The most recent change to the pneumococcal vaccination schedule at the start of 2020 provides an opportunity to reflect on the significance of this infection. This article also explains how the vaccination schedule has altered over time, detailing the rationale for the most recent change.
Pneumoccocal disease
Pneumococcal disease is a bacterial infection caused by Streptococcus pneumoniae. It is an encapsulated organism, which increases its virulence, and more than 90 different capsular types (serotypes) have been identified (Public Health England, 2020). It is reported that Streptococcus pneumoniae is frequently found in the nasopharynx of healthy individuals, and the risk of developing disease from this carriage is thought to depend on susceptibility of the individual and invasiveness of the bacteria (Southern et al, 2018). Infection with symptoms is commonly categorised as either non-invasive or invasive disease. Non-invasive disease occurs when the infection spreads locally to the middle ear and sinuses, resulting in otitis media and sinusitis, and more serious invasive disease can cause bacteraemic pneumonia and meningitis (Public Health England, 2020). Higher rates of invasive pneumococcal disease have been observed in the very young, older people, and individuals with impaired immune functioning (Public Health England, 2020). Prior to the introduction of routine vaccination against pneumococcal disease for children, in 2005/2006 there were over 6000 reported cases of invasive pneumococcal disease across all age groups in England and Wales (Ladhani et al, 2018).
Pneumococcal vaccination
In the UK, there are currently three vaccines that are licenced for use, and these provide protection against certain pneumococcal serotypes. The vaccines are distinguished by the serotypes included in each vaccine and also by vaccine type, although only two of these are used in the current UK schedule (Table 1).
Table 1. Pneumococcal vaccines currently available
| Vaccine name | Vaccine type | Serotypes included in vaccine |
|---|---|---|
| Prevenar 13® | Pneumococcal conjugate vaccine (PCV13) | 1, 3, 4, 5, 6A, 6B, 7F, 9V, 14, 18C, 19A, 19F, 23F |
| Synflorix®—not used in UK schedule | Pneumococcal conjugate vaccine (PCV10) | 1, 4, 5, 6B, 7F, 9V, 14, 18C, 19F, 23F |
| Pneumococcal Polysaccharide Vaccine® | Pneumococcal polysaccharide vaccine (PPV23) | 1, 2, 3, 4, 5, 6B, 7F, 8, 9N, 9V, 10A, 11A, 12F, 14, 15B, 17F, 18C, 19F, 19A, 20, 22F, 23F, 33F |
Adapted from Public Health England, 2020
The different vaccine types are the pneumococcal polysaccharide vaccine (PPV) and the pneumococcal conjugate vaccine (PCV). PPV23 offers protection against 23 serotypes, and this is the vaccine that is currently recommended for individuals identified as being in a group at higher risk of infection, and those over the age of 65 years. This vaccine should not be given to children under 2 years old; the antibody response may be poor and there is no evidence of its efficacy in children of this age (Goldblatt, 2000).
The development of conjugate vaccines has meant that protection against encapsulated polysaccharides like pneumococcus can be offered to younger children; by joining (conjugating) the polysaccharide to a protein, the immune response is greatly improved (Goldblatt, 2000). The current UK schedule advocates that children are vaccinated with PCV13, so they are protected against 13 of the serotypes commonly causing invasive disease.
When the pneumococcal conjugate vaccination was introduced in the UK in 2006, there followed a significant drop (98%) in the number of cases of invasive pneumococcal disease caused by PCV7-types in the vaccinated population; similarly, a reduction of 81% of PCV7-type invasive disease was also observed in adults over 65 years (Southern et al, 2018). This indirect protection demonstrated the vaccine's ability to affect carriage, resulting in herd immunity. This occurrence appears to be unique only to conjugate vaccines and has not been observed on this scale in other vaccine types (including PPV23).
Pneumococcal vaccination schedule changes
Vaccination against pneumococcal disease with PPV was first introduced for risk groups in 1992, and then for the over 65s in 2003. In 2006, routine vaccination for children began using a conjugate vaccine offering protection against seven serotypes—PCV7—and this vaccine was replaced with PCV13 in 2010 (Public Health England, 2020). The scheduling for the timing of these vaccines for children has also changed over time, with the number and timing of primary doses being altered to reflect epidemiological findings (Table 2).
Table 2. Changes to the pneumococcal vaccination schedule
| Year | Vaccine | Vaccine recipient | Schedule |
|---|---|---|---|
| 1992 | PPV23 | At risk groups | Single dose* |
| 2003 | PPV23 | 65 years+ | Single dose |
| 2006 | PCV7 | Children | 2 + 1 |
| 2010 | PCV13 | Children | 2 + 1 |
| 2020 | PCV13 | Children | 1 + 1 |
In children, initially, two priming doses of PCV7 were given, followed by a booster dose at 1 year (2 + 1 schedule). This schedule of three pneumococcal vaccinations given at 8 weeks, 16 weeks and 1 year remained the same, with the replacement of PCV7 with PCV13 in 2010. Most recently, in December 2019 plans were announced to reduce the number of priming doses from two to one (Public Health England, 2019), and this 1 + 1 schedule has been in effect for babies born on or after 1 January 2020. Doses are now given at 12 weeks and 1 year.
Rationale for recent change
The pneumococcal conjugate vaccination programme has been successful in the UK; it has reduced both the amount of carriage and circulating pneumococcal serotypes in the population, and the risk of infection with any of these serotypes is currently very low. The incidence of invasive pneumococcal disease in England has remained unchanged since 2013/2014, suggesting that the PCV13 programme of 2 + 1 has achieved its maximum effect (Ladhani et al, 2018). A recent randomised controlled trial by Goldblatt et al (2018) compared the 2 + 1 schedule to a 1 + 1 schedule in infants. They found the 1 + 1 schedule produced a similar antibody response to the 2 + 1 schedule. A further modelling study by Choi et al (2019) examined the impact of changing from a 2 + 1 to a 1 + 1 schedule; modelling studies are designed to estimate the impact of an intervention and are frequently used to inform policy decisions (Bennett and Manuel, 2012). Using modelling techniques, which included accounting for age and assessing over a period of time, Choi et al (2019) found that given the established PCV vaccination programme in England, a reduction in the number of priming doses would not have any significant impact on invasive pneumococcal disease or associated mortality at any age.
Keeping up to date with the vaccination schedule
Vaccination schedules are continually adapted to account for epidemiological findings and advances in vaccine technology. It is important that practices nurses remain fully informed; not only about what the changes are but also the rationale behind them. Dialogue with questioning parents is commonplace, and ensuring nurses are able to respond with accurate and contemporary information is vital (Bedford and Elliman, 2019). Table 3 lists some resources which nurses can use to ensure that they are familiar with the latest information about vaccines, procedures and policies.
Table 3. Resources
| Public Health England. Immunisationhttps://www.gov.uk/government/collections/immunisation-against-infectious-disease-the-green-book | This is the ‘Green Book’ and is regularly updated to reflect changes in vaccination policy |
| Public Health England. Vaccine Updatehttps://www.gov.uk/government/collections/vaccine-update | This is a resource which nurses can subscribe to. Generally, updates are monthly and provide information about vaccine policy and procedures |
| e-Learning for Healthcare. Immunisationhttps://www.e-lfh.org.uk/programmes/immunisation/ | Nurses who are involved in vaccination should attend basic training and undertake yearly updates. This is a training resource which can be used to support this |
Conclusion
Pneumococcal disease is a serious bacterial infection and vaccination with a schedule which is evidence-based means that changes to the immunisation schedule are inevitable. It is vital that practice nurses are aware of, and understand why such changes need to occur, so that they have the confidence to continue to have authentic discussions with parents.
CPD reflective practice:
- Can you describe pneumococcal infection?
- How would you explain the difference between the vaccine types—pneumococcal conjugate vaccine (PCV) and pneumococcal polysaccharide vaccine (PPV)?
- Can you describe the current pneumococcal vaccination schedule?
- How would you discuss the rationale for the recent changes to the vaccination schedule?
KEY POINTS:
- Streptococcus pneumoniae is frequently found in the nasopharynx of healthy individuals. The risk of developing disease from this carriage is thought to depend on susceptibility of the individual and invasiveness of the bacteria
- Higher rates of invasive pneumococcal disease have been observed in the very young, older people, and individuals with impaired immune functioning
- The introduction of pneumococcal conjugate vaccination led to a significant drop in the number of cases of invasive pneumococcal disease, as well as herd immunity for the rest of the population
- After research showed a 1 + 1 schedule is as effective as a 2 + 1 schedule, a new 1 + 1 schedule has been introduced for babies born on or after 1 January 2020. Doses are now given at 12 weeks and 1 year
- Practice nurses should ensure they remain up to date with changes to the vaccination schedule and the reasons behind this