Vaccine strategies to reduce the burden of pneumococcal disease in HIV-infected adults in Africa.

ABSTRACT

Introduction

Streptococcus pneumoniae is the leading cause of invasive bacterial disease, globally. Despite antiretroviral therapy, adults infected with human immunodeficiency virus (HIV) are also at high risk of pneumococcal carriage and disease. Pneumococcal conjugate vaccines (PCVs) provide effective protection against vaccine serotype (VT) carriage and disease in children, and have been introduced worldwide, including most HIV-affected low- and middle-income countries. Unlike high-income countries, the circulation of VT persists in the PCV era in some low-income countries and results in a continued high burden of pneumococcal disease in HIV-infected adults. Moreover, no routine vaccination that directly protects HIV-infected adults in such settings has been implemented.

Areas covered

Nonsystematic review on the pneumococcal burden in HIV-infected adults and vaccine strategies to reduce this burden.

Expert opinion

We propose and discuss the relative merit of changing the infant PCV program to use (1a) a two prime plus booster dose schedule, (1b) a two prime plus booster dose schedule with an additional booster dose at school entry, to directly vaccinate (2a) HIV-infected adults or vaccinating (2b) HIV-infected pregnant women for direct protection, with added indirect protection to the high-risk neonates. We identify key knowledge gaps for such an evaluation and propose strategies to overcome them.

KEYWORDS:

• Pneumococcus
• hiv
• pcv
• vaccination strategy

Article highlights

• Circulation of VTs persists in the PCV era in some low-income countries and results in a continued high and potentially vaccine-preventable burden of pneumococcal disease in HIV-infected adults.

• Routine pneumococcal vaccination programs for HIV-infected adults are not implemented in low-income countries.

• Mitigation of the VT-disease burden in HIV-infected adults in low-income countries may be achieved either by added direct protection or increased indirect protection from the infant program (via increased coverage or a change in vaccine schedule).

• For added direct protection both PCV and PPV are licensed and used in high-income countries. PCV is more immunogenic but also substantially more expensive and has inferior serotype coverage.

• For added indirect protection a change in infant immunization schedule to stipulate longer-lasting protection may largely mitigate the risk for vaccine-preventable pneumococcal disease in the HIV-infected.

• Both strategies will need a formal evaluation of their likely effectiveness and cost-effectiveness.

Author Contributions

DT, NF, and SF conceived the idea for the manuscript. DT wrote the first manuscript draft with support from AP, OJ, KEG, NF, and SF. All authors contributed to, and approved the final draft. All authors declare that they meet the ICMJE criteria for authorship.

Acknowledgments

We would like to thank Robert S Heyderman of the University College London, and John W Edmund of the London School of Hygiene and Tropical Medicine, in London, United Kingdom, for insightful discussions at the initial stage of this work.

Declaration of interest

D Thindwa, J Ojal, K E Gallagher, N French, and S Flasche are supported by the National Institute for Health Research (NIHR) Global Health Research Unit on Mucosal Pathogens using UK aid from the UK Government. The views expressed in this publication are those of the author(s) and not necessarily those of the NIHR or the Department of Health and Social Care. A Pinsent was supported by a grant from the Bill and Melinda Gates Foundation (OPP1139859). S Flasche is also supported by a Sir Henry Dale Fellowship jointly funded by the Wellcome Trust and the Royal Society (Grant number 208,812/Z/17/Z). 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 no relevant financial or other relationships to disclose.

Additional information

Funding

This manuscript was funded by the National Institute for Health Research (NIHR) Global Health Research Unit on Mucosal Pathogens using UK aid from the UK Government (16/136/46)