Why do who monitor influenza carefully

Either percentages of sites achieving timeliness targets or time lag averages can also be used as a quality metric to be followed over time. Indicators of completeness can be determined by analyzing reported data. They may include percentage of reports received from each site with complete data, percentage of total expected data reports received, and percentage of total expected cases that have specimens submitted to the laboratory depends on sampling scheme devised for sites. Emergence of new subtypes of influenza virus A in human populations is unusual and unlikely to be detected by a sentinel surveillance system, except by chance or if transmission is sustained.

Control of a pandemic caused by the introduction of a new subtype of influenza virus A will require early detection and recognition of the event. Although sentinel surveillance as a stand-alone system may not accomplish this, it has value in establishing the infrastructure necessary to respond to a pandemic. In addition to providing a basic understanding of the epidemiology of influenza transmission and risk, a routine reporting system would produce an infrastructure for reporting, specimen processing and testing, and data collection and analysis.

It would make data interpretation more routine and thus more manageable in the face of a pandemic emergency and drive interest in influenza-associated disease and vaccination. After a novel strain of influenza emerges, monitoring its course is necessary to determine whether cases are increasing or decreasing, to detect changes in patient age distribution or other epidemiologic characteristics, to detect changes in mortality rates, and to monitor changes in susceptibility to antiviral agents.

In the midst of an outbreak, national monitoring may not be necessary or feasible, and most, if not all, critical information can be gained from a few sentinel sites.

Emergence of a new strain of influenza increases the data needs of health policy makers. Historical surveillance data for comparison can facilitate the understanding of answers to critical questions such as severity of the outbreak related to a new strain and its potential to adversely affect healthcare delivery. An existing surveillance infrastructure also provides the platform needed to describe the clinical course of emerging pathogens, risk factors for severe outcomes, and effectiveness of control measures.

Surveillance for SARIs can provide critical understanding of the contribution of influenza infection to the global burden of disease, provide a platform for the study of other common respiratory pathogens, and strengthen public health infrastructure. Such a system should be a part of a routine surveillance program to provide data needed for allocation of scarce healthcare resources. Victor, and the manuscript peer reviewers. His research interest is the clinical epidemiology of respiratory infections found in tropical regions.

Strategy to enhance influenza surveillance worldwide. Emerg Infect Dis [serial on the Internet]. National Center for Biotechnology Information , U. Journal List Emerg Infect Dis v. Emerg Infect Dis. Justin R. Ortiz , Viviana Sotomayor , Osvaldo C. Bresee , and Anthony W. Author information Copyright and License information Disclaimer. Bettels, M. McCarron, J. Bresee, A. Corresponding author.

Address for correspondence: Anthony W. Copyright notice. This article has been cited by other articles in PMC. Abstract The emergence of a novel strain of influenza virus A H1N1 in April focused attention on influenza surveillance capabilities worldwide. Keywords: influenza, human influenza influenza A virus, avian influenza, H5N1 subtype, sentinel surveillance, epidemiology, viruses, policy review.

Influenza in Developing Countries Virus transmission or clinical presentation may be altered by differences in cultural practices, the environment, geography, human genetics, and social structures.

Objectives The most efficient process for producing high-quality epidemiologic data for influenza-associated illness is sentinel surveillance. Open in a separate window. Sentinel Site Selection Ideally, sites should represent a wide cross-section of ethnic and socioeconomic groups and should be in different climatic regions.

Data Collection Minimum data elements are outlined in Table 2. Specimen Collection Respiratory specimens should be collected early from all SARI patients, following established protocols Integration into National Reporting Systems In countries with established national disease reporting systems, such as the Integrated Disease Surveillance Reporting system used in Africa 25 , sentinel surveillance for SARI can be incorporated into the existing system.

Outpatient Surveillance The highest priority should be to collect data on SARI cases because they contain the most influenza-associated disability and premature death. Data Analysis and Reporting Timely analysis and reporting of surveillance data will facilitate treatment decisions by clinicians and control measures by public health officials.

Evaluation and Quality Assurance The usefulness of surveillance data will depend directly on the quality of the data; every system should have a quality assurance program. Timeliness a. Several time intervals are appropriate for routine measurement as quality indicators. These include the duration of time from i.

Target date for data reporting from the sentinel site to the next administrative level until the actual reporting date ii. Target date for data reporting from the next administrative level to the national level until the actual reporting date iii.

Date of specimen collection at facility until shipment to laboratory iv. Date of result availability in laboratory until date of report to referring institution and physician v. Date of receipt of specimen in the laboratory until result availability b. Two metrics can be used to reflect timeliness indicators: i. Percentage of time that a site achieves target for timeliness ii.

Average number of days for each interval over time for each site 2. Completeness a. Percentage of reports received from each site with complete data b. Percentage of data reports that are received c.

Percentage of reported cases that have specimens collected 3. Regular field evaluations and audits at facility level of a subset of medical records to ensure a.

Cases are being counted appropriately and not being underreported b. Reported cases fit the case definition c. Epidemiologic data are correctly and accurately abstracted d.

Respiratory samples are being taken, stored, processed, tested, and shipped properly and in a timely fashion from all those who meet sampling criteria e.

Sampling procedures are being done uniformly without evidence of bias 4. Data to be followed and observed for aberrations over time a. Number of cases reported by month for each site b.

Number of specimens submitted by month for each site c. Percentage of specimens that are positive for influenza d. Data Validity Regular field evaluations and audits at a facility level must be a standard component of the system. Timeliness To be useful, collection and reporting of surveillance data must be timely.

Completeness Indicators of completeness can be determined by analyzing reported data. Pandemic Early Warning Systems and Monitoring Emergence of new subtypes of influenza virus A in human populations is unusual and unlikely to be detected by a sentinel surveillance system, except by chance or if transmission is sustained.

Conclusions Surveillance for SARIs can provide critical understanding of the contribution of influenza infection to the global burden of disease, provide a platform for the study of other common respiratory pathogens, and strengthen public health infrastructure. References 1. N Engl J Med. May 28; [Epub ahead of print]. World Health Organization WHO consultation on priority public health interventions before and during an influenza pandemic; Mar 16—18; Geneva [cited Apr 22].

Oshitani H, Kamigaki T, Suzuki A Major issues and challenges of influenza pandemic preparedness in developing countries. Minus Related Pages. Related Links. What CDC Does. To receive weekly email updates about Seasonal Flu, enter your email address: Email Address.

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