Challenges of global surveillance during an influenza pandemic

Abstract

Surveillance is an essential foundation for monitoring and evaluating any disease process, and is especially critical when new disease agents appear. The H1N1 influenza pandemic of 2009 tested the capacities of countries to detect, assess, notify and report events as required by the 2005 International Health Regulations (IHR). As detailed in the IHR, the World Health Organization drew on official reports from Member States as well as unofficial sources (e.g., media alerts) to quickly report and disseminate information about the appearance of the novel influenza virus. The pre-existing Global Influenza Surveillance Network for virological surveillance also provided crucial information for rapid development of a vaccine and for detection of changes in the virus. However, the pandemic also highlighted a number of shortcomings in global epidemiological surveillance for respiratory disease. These included the lack of standards for reporting illness, risk factor and mortality data, and a mechanism for systematic reporting of epidemiological data. Such measures would have facilitated direct comparison of data between countries and improved timely understanding of the characteristics and impact of the pandemic. This paper describes the surveillance strategies in place before the pandemic and the methods that were used at global level to monitor the pandemic. Enhancements of global surveillance are proposed to improve preparedness and response for similar events in the future.

Assessing the impact of a health intervention via user-generated Internet content

“…Typically, these schemes, apart from requiring an established health system, only cover cases that result in healthcare service utilization. Therefore, they are not always able to capture the prevalence of a disease in the general population, where it is likely to be more common (Reed et al 2009;Briand et al 2011).…”

The spatiotemporal association of non-prescription retail sales with cases during the 2009 influenza pandemic in Great Britain

“…These methods (often referred to as Syndromic Surveillance Systems) offer a real-time or near-real-time collection of data from a variety of sources, ideally in an automated manner which allows early identification of the spread and impact of emerging public health threats and better estimates of incidence in seasonal outbreaks 3. The 2009 influenza pandemic provided the motivation to adopt and appraise many of these methods 4 5. In the UK many of the lessons learned during this time were subsequently adopted during the 2012 Olympics and Paralympics to identify any early infectious disease threat 6…”

Fatiga de vigilancia (fatigatio vigilantiae) durante epidemias

“…Epidemiological studies at the beginning of an epidemic could correctly reflect numbers of people infected (Figure 1), but posterior limitations in laboratory supplies or personnel can lead to surveillance fatigue. For example, in the pandemic of influenza A H1N1 in 2009, countries with strong surveillance systems faced difficulties to maintain accurate case reporting due to overwhelming epidemic; in this scenario, laboratory diagnosis supplies were consumed before the peak of the epidemic, undermining surveillance 7 . During the Ebola epidemic in 2014, an underestimation of cases in Liberia was clearly identified and described in reports of the World Health Organization 8 .…”

“…Estudios epidemiológicos al comienzo de una epidemia podrían reflejar correctamente el número de personas infectadas (Figura 1), pero limitaciones posteriores en los suministros de laboratorio o del personal pueden conducir a fatiga de vigilancia. Por ejemplo, en la pandemia de influenza A H1N1 en 2009, países con sistemas de vigilancia fuertes tuvieron dificultades para mantener un informe preciso de los casos debido a sus características abrumadoras; en este escenario, los suministros de diagnóstico de laboratorio fueron consumidos antes del pico de la epidemia, socavando la vigilancia 7 . Durante la epidemia de Ébola en 2014, una sub-estimación de casos en Liberia fue claramente identificada y descrita en los informes de la Organización Mundial de la Salud 8 .…”