A review of evidence for pneumococcal vaccination in adults at increased risk of pneumococcal disease: risk group definitions and optimization of vaccination coverage in the United Kingdom

ABSTRACT

Introduction

Pneumococcal disease (PD) significantly contributes to morbidity and mortality, carrying substantial economic and public health burden. This article is a targeted review of evidence for pneumococcal vaccination in the UK, the definitions of groups at particular risk of PD and vaccine effectiveness.

Areas covered

Relevant evidence focusing on UK data from surveillance systems, randomized controlled trials, observational studies and publicly available government documents is collated and reviewed. Selected global data are included where appropriate.

Expert opinion

National vaccination programs have reduced the incidence of vaccine-type PD, despite the rising prominence of non-vaccine serotypes in the UK. The introduction of higher-valency conjugate vaccines provides an opportunity to improve protection against PD for adults in risk groups. Several incentives are in place to encourage general practitioners to vaccinate risk groups, but uptake is low-suboptimal particularly among at-risk individuals. Wider awareness and understanding among the public and healthcare professionals may increase vaccination uptake and coverage. National strategies targeting organizational factors are urgently needed to achieve optimal access to vaccines. Finally, identifying new risk factors and approaches to risk assessment for PD are crucial to ensure those at risk of PD can benefit from pneumococcal vaccination.

KEYWORDS:

• Clinical risk group
• community acquired pneumonia
• epidemiology
• invasive pneumococcal disease
• pneumococcal conjugate vaccine
• pneumococcal polysaccharide vaccine
• vaccination guidelines
• vaccination uptake

Article highlights

• National vaccination programs have helped reduce the incidence of vaccine-type PD in the UK, but there have been concerns on the emerging incidence of PD caused by non-vaccine serotypes (i.e. non-PCV13, non-PPV23).

• The introduction of higher-valency conjugate vaccine options (i.e. PCV15, PCV20) within the UK provides an opportunity to help address the challenges associated with serotypes replacement. These new pneumococcal conjugate vaccines provide broader serotype coverage, as these contain new serotypes (in addition to PCV13) responsible for PD cases in the UK, particularly in adults aged ≥65 years, and thus potentially offering improved and direct protection against PD for adults in risk groups.

• Two new higher-valency pneumococcal conjugate vaccines, PCV15 and PCV20, are licensed and available in the UK; both vaccines have been introduced into vaccination guidelines in the US and some European countries. In the UK, the JCVI has now recommended that PCV20 should be used for adults in risk groups.

• Within the risk categories defined in the guidelines, occupational risk factors are limited to metal workers and welders. However, other professional activities involving close contact with people with respiratory disease could be considered as relevant for pneumococcal vaccination (e.g. individuals working in residential care homes, elderly care wards, oil rigs, prisons, those living in inner city high pollution settings and healthcare workers), since they are at higher risk of exposure to respiratory infections.

• The effect of risk stacking (defined as the increase in risk of PD with the accumulation of concurrent at-risk conditions) has not yet been formally considered and should be taken into consideration when making recommendations for pneumococcal vaccines. Reassessment of risk groups deemed eligible for pneumococcal vaccination may be beneficial for prevention of PD.

• Several unmet needs and challenges for the management of PD have been identified, including the resurgence of PD cases post COVID-19 restrictions, the continuous pressure on the National Healthcare Service’s capacity for delivery of patient care, and global concerns on antimicrobial resistance. Some of these issues may be addressed through pneumococcal vaccination.

• Available data suggest that the PPV23 uptake rate varies by risk factor and remains low particularly in adults with risk conditions. The PPV coverage report published by the UK Health Security Agency estimated that the PPV23 coverage up to 2021 in eligible individuals (aged 2–64 years) ranged between 38.5% for those with chronic liver disease and 56.0% for those with chronic respiratory disease, while uptake rate was 70.7% for those with cochlear implants.

• Barriers affecting vaccination uptake include vaccine hesitancy (inadequate knowledge, low awareness, negative attitudes) toward vaccinations among patients and some GPs and patient access (convenience) to routine vaccinations. We also speculate that low vaccination uptake may be attributable to organizational factors.

• Although various incentives are in place to encourage GPs to vaccinate patients at risk of PD, national strategies are still needed to optimize vaccine uptake and patient access to vaccines may be informed by learnings from vaccine delivery approaches implemented during the COVID-19 pandemic.

Acknowledgments

The authors thank Dr Peter Elton (Clinical Director) of the Greater Manchester and Eastern Cheshire Strategic Clinical Networks for his contribution to the conceptualization of this article. Additionally, Professor Dave Singh is supported by the National Institute for Health Research (NIHR) Manchester Biomedical Research Centre (BRC).

Declaration of interests

J Campling, A Vyse, H Wright, and G Ellsbury are employees of Pfizer Ltd, UK, and may hold stock or stock options. HH Liu is an employee of OPEN Health. M Slack has received personal fees from GlaxoSmithKine, Pfizer, Merck, AstraZeneca, and Sanofi Pasteur as a speaker at international meetings and as a member of advisory boards and has undertaken contract work for Pfizer. RR Reinert is an employee of Pfizer Inc, France, and may hold stock or stock options. M Drayson owns equity/stocks in Abingdon Health outside the submitted work. D Singh has received consultancy fees from Aerogen, AstraZeneca, Boehringer Ingelheim, Chiesi, Cipla, CSL Behring, EpiEndo, Genentech, GlaxoSmithKline, Glenmark, Gossamer Bio, Kinaset Therapeutics, Menarini, Novartis, Orion, Pfizer, Pulmatrix, Sanofi, Synairgen, Teva, Theravance Biopharma, and Verona Pharma. G Barlow is Senior Clinical Lecturer at Hull York Medical School at the University of York and an Honorary Consultant in Infection at Hull University Teaching Hospitals NHS Trust. Within the last three years, G Barlow has received advisory board or consultation fees from Advanz Pharma, Pfizer UK and Biomerieux. G Kassianos works as a National Immunisation Lead RCGP, President British Global & Travel Health Association, Board Member European Working Scientific Group on Influenza, and Chair RAISE Pan-European Group of experts in influenza, and has participated at meetings organized by all vaccine manufacturers in the UK. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

Reviewer disclosures

Peer reviewers on this manuscript have received an honorarium for their review work. Peer reviewers on this manuscript have no other relevant financial or other relationships to disclose.

Author contributions

All authors have (1) substantially contributed to the conception and design of the review article and interpreting the relevant literature and (2) have been involved in writing the review article and have revised it for intellectual content.

Supplementary Material

Supplemental data for this article can be accessed online at https://doi.org/10.1080/14760584.2023.2256394

Correction Statement

This article has been corrected with minor changes. These changes do not impact the academic content of the article.

Additional information

Funding

This study was funded by Pfizer Ltd, UK. Medical support was provided by Hui-Hsuan Liu at OPEN Health and was funded by Pfizer.