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.
recent population-based study in Nova Scotia demonstrated that women at all stages of pregnancy are at increased risk of serious respiratory illness during influenza season, even in the absence of pre-existing co-morbid conditions known to increase the risk of influenza-associated morbidity. 1 The rate of hospitalization observed in this study among healthy pregnant women exposed to influenza season during their third trimester (65/100,000) was comparable to observed rates among American adults aged 15-44 years with co-morbid medical conditions (56-110/100,000), 2 a group for whom annual influenza immunization is already recommended. 3 However, while the US Advisory Committee on Immunization Practices 3 and the Canadian National Advisory Committee on Immunization 4 both recommend annual influenza immunization for all pregnant women, uptake in Nova Scotia is low (<3%). 5 Inactivated influenza vaccine has a long record of use in pregnant women and is considered safe in all stages of pregnancy. 6,7 Influenza vaccination in pregnant women may help prevent influenza-related physician and hospital utilization, but the economic implications of such a policy are unclear. We developed an economic model to estimate the incremental cost-effectiveness of targeted and universal vaccination strategies relative to a no-vaccination strategy in pregnant women in Nova Scotia, Canada. METHODS The evaluation compared targeted vaccination of pregnant women with one or more co-morbidities, universal vaccination of all pregnant women, and no-vaccination strategies. The evaluation was performed in Excel (Microsoft; Redmond, Washington) using Palisade Decision Tools (Palisade; Newfield, New York) to construct the decision tree (Figure 1) and to perform the probabilistic sensitivity analysis. The decision tree characterized costs and consequences over a one-year horizon, including the acquisition and administration costs of vaccination and the costs and quality-oflife consequences of influenza-related events and vaccination-related adverse effects. As all events in the evaluation occurred within one year, neither costs nor outcomes were discounted. The research project was approved by the Capital District Health Authority Research Ethics Board. Event rates Baseline event rates were derived from an analysis of a populationbased cohort of 134,188 pregnancies extracted from health admin
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.