In the first paper of The Lancet Series on the New Decade of Vaccines, Professor Richard Moxon, University of Oxford and John Radcliffe Hospital, Oxford, UK, and Professor Claire-Anne Siegrist, Geneva University Hospitals, Switzerland, discuss societal and scientific challenges for vaccines in the next 10 years.
In the past century, the judicious use of vaccines against microbial diseases has improved the health of millions of people. Vaccines have eliminated or substantially diminished the toll of major scourges, including smallpox, poliomyelitis, measles, pertussis, tetanus, yellow fever, and diphtheria. In the past two decades, great progress has been made in prevention of meningitis, pneumonia, and hepatitis.
Yet while acknowledging these successes, the authors point out that hurdles remain in the way of further progress. In the past, successful vaccines were largely developed by identification of antigens that induced immune responses to conserved pathogen components, whereas, in the future, a major challenge is to develop vaccines against deadly diseases in which the target antigens have extensive antigenic variability, such as HIV and malaria.
Other technical challenges to progress remain. There is a need for vaccines to be generated to protect the people who are most vulnerable because of age or underlying diseases. And another major challenge is how to develop vaccines capable of conferring lifelong protection without the need for repeated booster immunisations. To increase vaccine safety, use of subunit antigens* has been increasing, but these antigens are devoid of the natural adjuvant properties typical of whole-cell vaccines, and, therefore, are less immunogenic, and need novel strategies to increase immunogenicity. The molecules and pathways through which antigen-presenting cells drive specific and effective T cell formation is crucial for further progress in vaccine development. The authors also highlight issues raised by the recent H1N1 influenza pandemic, where existing technology to make vaccines was not fast enough to keep pace with the rapid spread of this pandemic strain.
In addition to the technical challenges facing vaccines themselves, other developments in biological science—such as pharmacogenomics—could increasingly reveal how individuals are likely to react to vaccines and result in tailored vaccination programmes suited to the individual. For example, recognition of individuals having a genetic predisposition to adverse reactions to specific vaccines could result in more selective immunisation policies and increase the safety of immunisation.
Despite the extraordinary past achievements in immunisation and the future application of new technologies to provide future improved and novel vaccines, the basis of these science-driven benefits must be communicated effectively if the benefits to global public health are to be realised. The authors say: "The public needs to regain confidence in immunisation and trust the organisations responsible for the research, development, and implementation of vaccines...In informing the public, advocates need to achieve a balance between the benefits of immunisation and acknowledgment of possible adverse outcomes."
Societal and Scientific Challenges in the Next Decade of Vaccines
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