The proportion of contemporary invasive pneumococcal disease and pneumococcal pneumonia in UK adults reflected by serotypes included in the 13-valent pneumococcal conjugate vaccine and next generation higher valency pneumococcal conjugate vaccines in development

Abstract

The UK introduced a pneumococcal conjugate vaccine (PCV) that covered seven serotypes (PCV-7) for routine infant immunisation in 2006 which was replaced with a 13 valent PCV (PCV-13) in 2010 [1]. This resulted in major reductions in the vaccine type pneumococcal disease burden across all age ranges due to both direct and indirect protection [2]. PCV-13 is also licensed in the UK for the prevention of invasive pneumococcal disease (IPD) and pneumococcal pneumonia in adults but is currently only recommended for very high-risk adults in the UK. At present all UK adults aged 65+ years and those considered at increased risk of pneumococcal infection are routinely offered a single dose of the 23-valent pneumococcal polysaccharide vaccine (PPV-23) with re-vaccination recommended for patients with chronic renal disease and asplenia/splenic dysfunction [1]. However, PPV-23 has only limited short term effectiveness against IPD in UK adults aged 65+ years with no impact achieved at the population level [3]. There is also a lack of consistent evidence showing PPV-23 effectiveness against adult community acquired pneumonia (CAP), which reflects a much larger disease burden compared to adult IPD with the pneumococcus an important cause [4]. Since 2013/14 there has been a rapid increase in IPD in older UK adults aged 65+ years that is especially attributed to several PPV-23 non PCV-13 (PPV-23non13) serotypes [2]. Next generation higher valency PCVs (PCV-15 and PCV-20) that include some PPV-23non13 serotypes are now in advanced stages of development [5], [6]. These are anticipated to shortly become available for use in adults and may offer new opportunities to protect UK adults against pneumococcal disease. The serotypes included in currently available pneumococcal vaccines (PCV-13, PPV-23) and next generation higher valency PCVs (PCV-15, PCV-20) are shown in Table 1.