Novel framework for assessing epidemiologic effects of influenza epidemics and pandemics.

The effects of influenza on a population are attributable to the clinical severity of illness and the number of persons infected, which can vary greatly between seasons or pandemics. To create a systematic framework for assessing the public health effects of an emerging pandemic, we reviewed data from past influenza seasons and pandemics to characterize severity and transmissibility (based on ranges of these measures in the United States) and outlined a formal assessment of the potential effects of a novel virus. The assessment was divided into 2 periods. Because early in a pandemic, measurement of severity and transmissibility is uncertain, we used a broad dichotomous scale in the initial assessment to divide the range of historic values. In the refined assessment, as more data became available, we categorized those values more precisely. By organizing and prioritizing data collection, this approach may inform an evidence-based assessment of pandemic effects and guide decision making.

Workshop on intussusception in African countries--meeting report.

Rotavirus causes approximately 450,000 deaths annually among children less than 5 years of age worldwide, almost half of which occur in Africa. After the recent completion of successful trials of 2 new rotavirus vaccines, the World Health Organization has recommended these vaccines for all children worldwide. Because a previous rotavirus vaccine, Rotashield(®), was associated with intussusception, a form of intestinal obstruction among infants, the current rotavirus vaccines were tested in large clinical trials and found to be safe. However, due to the past Rotashield(®) experience, post licensure monitoring of intussusception is considered to be crucial after the introduction of future oral rotavirus vaccines. Thus, in planning for future introductions of rotavirus vaccine in Africa, a workshop of experts working on intussusception was convened by the World Health Organization in May 2004 in association with the Pan-African Association of Paediatric Surgeons (PAPSA) in Malawi. In brief, delegates from ten countries presented data from retrospective record reviews of intussusception events from 1993 to 2003 at selected hospitals in their respective countries. This review showed that age of intussusception onset during infancy varies markedly with peak prevalence between 4 and 6 months of life. Diagnostic modality (e.g., contrast enema, ultrasound) was employed in <20% of the events; nearly 70% of the intussusception events were diagnosed at the time of surgery. Overall, case-fatality was high, ~13%, in these African countries. The findings of this meeting highlight the challenges in implementing surveillance for intussusception after rotavirus vaccine introduction in Africa. The deliberations identified some concrete steps necessary to establish active surveillance at sentinel sites in African countries. This is becoming more urgent now that many countries are expressing interest in introducing rotavirus vaccines.