Notable Practices

Media Surveillance
GPHIN and ProMED-mail are chief sources of reports sent to WHO. GPHIN’s global coverage is extensive; this is primarily attributable to evaluation of news media in seven languages. Between 1998 and 2001, WHO’s Outbreak Alert and Verification System confirmed 578 outbreaks, of which 56% were initially picked up by GPHIN.

ProMED-mail uses in-country infectious disease experts to improve the credibility of outbreak reports. The experts review preliminary reports and often request additional information about suspected outbreaks. ProMED-mail was the source of the first SARS report and a recent outbreak of yellow fever in Brazil.

The ProMED-mail program also is a model for an affordable surveillance system that may be suitable for countries with limited resources. The basic requirements are modest: a university-based server, a website manager, and the personal computers of the subject matter volunteers. Since 1994, national ProMED-mail systems have been established in Brazil, the Netherlands, and South Korea. However, the governments of many countries are reluctant to implement a national version of ProMED-mail, because subscriber-based input may circumvent official reports of the ministry of health.29

Real-Time Surveillance
The time interval between the beginning of an epidemic and recognition of the epidemic affects the magnitude of the epidemic and, consequently, the magnitude of the response required to contain it. Real-time surveillance theoretically reduces the time interval between outbreak and detection. QFLU is a surveillance program that approximates a real-time (24-hour) clinical surveillance and reporting capability. This time frame is possible because of the National Health Service electronic record system. QFLU uses analytical tools to monitor the timing, magnitude, and spread of seasonal and/or pandemic influenza. This report, updated daily, contributes to situational awareness and informs decisions about use of drugs, vaccines, and infection control measures. A pilot study was conducted to measure the robustness of QFLU’s case-definition–based clinical diagnosis. Laboratory results of nasal swabs from patients with influenzalike illness indicated that, during seasonal flu, the clinical diagnosis of influenzalike illness is a sensitive indicator of influenza (A. Cooper, personal communication, Fall 2006). QFLU is designed to protect confidentiality by collecting only patient age and sex.

Influenza Surveillance
Annual influenza vaccination reduces morbidity, mortality, and healthcare costs; the effectiveness of influenza vaccines is, in large part, attributable to the Global Influenza Surveillance Network (GISN). Information about circulating influenza viruses is the basis for strain selection for annual flu vaccines. The network has developed and adheres to rigorous standards, exemplified by those established by the European Influenza Surveillance Scheme (EISS). These standards of operation contribute to the reliability of vaccine strain selection and also facilitate recognition of unusual clusters of influenza cases and identification of strains with pandemic potential.

In response to the avian influenza pandemic, GISN has worked to integrate human and veterinary surveillance. Designated H5N1 laboratories conduct comparative analysis of animal, mammalian, and human strains. GISN also has supported H5N1 disease outbreak response capabilities by aiding GOARN partners in epidemiologic investigations in affected countries. GISN collaborates with the U.N.’s Food and Agriculture Organization and other expert groups to (1) develop operational definitions of a cluster of cases of influenza attributable to human-to-human transmission; (2) recommend strategies to prevent transmission of H5N1 from poultry to humans; and (3) improve H5N1 surveillance capabilities in affected and vulnerable countries. GISN’s laboratory infrastructure is well established in 87 countries and could be expanded to include other zoonotic and emerging diseases with potential impact on international public health.

Vaccine-Preventable Illness Surveillance
The Global Polio Eradication Initiative and the Regional Immunization Program of the Americas illustrate surveillance and response programs that use a case-definition/ laboratory confirmation–based surveillance system linked to immunization programs to control vaccine-preventable illness. The GPEI program has made a significant impact on the prevalence of polio throughout the world. This is remarkable given that the majority of polio infections are asymptomatic. Two practices contribute to this success: GPEI has a quality assurance program that evaluates laboratories for proficiency and recertifies them every 1–2 years, and the program achieves high vaccination rates (~90%) during immunization campaigns.

Recently, polio network laboratories in 125 countries have expanded the scope of epidemiologic and laboratory testing of diseases to other viruses including the pathogens that cause measles, yellow fever, hemorrhagic fevers, meningitis, Japanese encephalitis, and SARS. Since the emergence of H5N1, GPEI teams in Nigeria and India have been involved in epidemiologic investigations of avian influenza.54

The Regional Immunization Program of the Americas targets vaccine preventable illnesses that affect the health of the public. The program has created national infrastructure for surveillance and response (23,000 sentinel sites throughout Latin America and the Caribbean) and a central data collection network to enhance regional cooperation, which could be expanded to cover other emerging diseases. The Revolving Fund is an integral part of the success and sustainability of the PAHO program, because it guarantees adequate supplies of affordable vaccines. Another key component of the longevity and success of the program is the in-country capacity building, which is facilitated by a small team (14) of international consultants and a regional technical advisory group.

Emerging Diseases Surveillance
Three programs illustrate systems focused on detection of emerging diseases and improvement of regional capacities for surveillance and response: the Global Disease Detection Program (GDD), the Global Emerging Infections Surveillance and Response System (GEIS), and the Biological Threat Reduction Program (BTRP).

The GDD program is strengthening infrastructure in host countries by building on established CDC programs. Improvements are planned in applied epidemiology and public health practice and better integration of disease surveillance and outbreak response capabilities, including augmenting molecular diagnostic capabilities. GEIS includes laboratories that have molecular- and culture-based diagnostic capabilities that have supported analysis of H5N1 strains and the infectious disease isolates associated with the 2004 Indian Ocean tsunami. GEIS also has collaborated to strengthen regional surveillance network capabilities. The Early Warning Outbreak Recognition System is used by Indonesia, Cambodia, Laos, Vietnam, and Peru. ASEAN-Outbreak.Net is used by 10 Asian countries and the WHO regional offices; usage has increased from just over 1,000 unique users in May 2003 to 15,000 in May 2004 to 23,000 in 2005.50

BTRP has standardized reagents, protocols, methods, and performance metrics that contribute to accurate reporting, verification, and rapid, effective response to outbreaks of emerging diseases. The program also has begun to strengthen linkages between human and veterinary programs; one of the centers investigated wild bird die-off near the border of Kazahkstan and isolated H5N1 virus from affected birds. To better serve the public health needs of the host countries, BTRP will be expanded in collaboration with other co-sponsors to include drug-resistant tuberculosis, rabies, cholera, malaria, and other diseases.

Guidelines for Surveillance and Response
The Epidemic and Pandemic Alert and Response (EPR) program provides international guidelines and manuals including, but not limited to, protocols to assess surveillance systems, software to help analyze and compare data, and databases to track the occurrences of diseases over time for 15 epidemic-prone diseases. Such standards provide benchmarks for early detection and effective response to disease outbreaks.

Outbreak Verification
Outbreak verification and response were represented by three international programs: WHO’s Outbreak Alert and Verification System, the European CDC’s Preparedness and Response Unit, and WHO’s Global Outbreak and Alert Response Network (GOARN).

The Outbreak Alert and Verification System compiles the Outbreak Verification List (OVL). This confidential weekly report is sent electronically to a selected group of public health professionals around the world. The individuals who receive the OVL communicate directly with WHO staff about the potential ramifications of the putative disease outbreaks and necessary epidemic responses. The outbreak reports on the OVL are unverified, so it is not made available to the public; this precaution limits any unnecessary impact on trade and travel in instances where the outbreak report is not confirmed or not considered to be of international public health significance.

Outbreak Response
The European Preparedness and Response Unit has strengthened regional coordination in Europe and includes non-EU member countries. In terms of strengthening Member States’ capacities for outbreak investigation and response, the unit’s training program, European Programme for Intervention Epidemiology Training, has trained approximately 130 European epidemiologists in the past 10 years.

Since 2000, WHO/GOARN has responded to more than 50 outbreaks worldwide.25 The SARS outbreak of 2003 was the first time GOARN teams responded to an outbreak of an unknown infectious disease.2 During the first 6 months of 2006, WHO/GOARN mobilized more than 70 operational interventions in response to avian influenza (AI) outbreaks and human transmission.55