The Expanded Program on Immunization (EPI) has led to large reductions in morbidity and mortality among children in low-income countries. However, the basic EPI schedule may no longer be optimal because of changes in vaccines, programs, and epidemiologic circumstances. In addition, evidence has accumulated that some EPI vaccines may have nonspecific effects that increase or decrease mortality from subsequent infections with other unrelated organisms. There is therefore a need for randomized trials to evaluate the effects of alternative EPI schedules on all-cause mortality, as well as vaccine efficacy against the target diseases. We have reviewed the available literature on the nonspecific effects of vaccines on mortality, and compiled a list of potential trials that might address this issue. We have then ranked the trials based on the potential importance of the results and the ethical and practical considerations. Trials of early BCG vaccination in low-birth-weight babies, early measles vaccination, and altered timing of DTP vaccination all have a high priority.
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From the *Intensive Care Unit, Royal Children's Hospital, Melbourne, Australia; †National Public Health Institute, Helsinki, Finland; ‡KEMRI Wellcome Trust Collaborative Research Programme, Kilifi, Kenya; §Nuffield Department of Clinical Medicine, University of Oxford, Oxford, United Kingdom; ¶Department of Paediatrics and Child Health, Desmond Tutu TB Centre, Stellenbosch University, Cape Town, South Africa; and ∥Medical Research Council Laboratories, Fajara, The Gambia.
Accepted for publication November 3, 2009.
Supported by the Novo Nordisk Foundation, and the Danish National Research Foundation; the World Health Organization supported the participation of some of the delegates.
This paper is the product of a workshop that was held in London in April 2008. The workshop was organized by Peter Smith from the London School of Hygiene & Tropical Medicine.
Address for Correspondence: Frank Shann, MD, FRACP, Royal Children's Hospital, Parkville, Victoria 3052, Australia. E-mail: firstname.lastname@example.org.
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